diff --git a/crates/ast/src/lang/core/expr/expr_to_expr2.rs b/crates/ast/src/lang/core/expr/expr_to_expr2.rs
index e47fe69bab..62d6a5d6dd 100644
--- a/crates/ast/src/lang/core/expr/expr_to_expr2.rs
+++ b/crates/ast/src/lang/core/expr/expr_to_expr2.rs
@@ -352,7 +352,7 @@ pub fn expr_to_expr2<'a>(
 
             for (node_id, branch) in can_branches.iter_node_ids().zip(branches.iter()) {
                 let (can_when_branch, branch_references) =
-                    canonicalize_when_branch(env, scope, *branch, &mut output);
+                    canonicalize_when_branch(env, scope, branch, &mut output);
 
                 output.references.union_mut(branch_references);
 
diff --git a/crates/ast/src/lang/core/expr/introduced_vars.rs b/crates/ast/src/lang/core/expr/introduced_vars.rs
index 26bbe6b738..91d5b7cdbe 100644
--- a/crates/ast/src/lang/core/expr/introduced_vars.rs
+++ b/crates/ast/src/lang/core/expr/introduced_vars.rs
@@ -3,7 +3,7 @@ use roc_module::ident::Lowercase;
 use roc_module::symbol::Symbol;
 use roc_types::subs::Variable;
 
-#[derive(Clone, Debug, PartialEq, Default)]
+#[derive(Clone, Debug, PartialEq, Eq, Default)]
 pub struct IntroducedVariables {
     // Rigids must be unique within a type annotation.
     // E.g. in `identity : a -> a`, there should only be one
diff --git a/crates/cli/tests/cli_run.rs b/crates/cli/tests/cli_run.rs
index 67e86bdd4e..bebd47ff0b 100644
--- a/crates/cli/tests/cli_run.rs
+++ b/crates/cli/tests/cli_run.rs
@@ -301,8 +301,8 @@ mod cli_run {
         test_many_cli_commands: bool, // buildOnly, buildAndRun and buildAndRunIfNoErrors
     ) {
         let file_name = file_path_from_root(dir_name, roc_filename);
+        let mut roc_app_args: Vec<String> = Vec::new();
 
-        let mut roc_app_args: Vec<String> = vec![];
         for arg in args {
             match arg {
                 Arg::ExamplePath(file) => {
@@ -320,10 +320,10 @@ mod cli_run {
         }
 
         // workaround for surgical linker issue, see PR #3990
-        let mut custom_flags: Vec<&str> = vec![];
+        let mut custom_flags: Vec<&str> = Vec::new();
 
         match executable_filename {
-            "form" | "hello-gui" | "breakout" | "ruby" => {
+            "form" | "hello-gui" | "breakout" | "libhello" => {
                 // Since these require things the build system often doesn't have
                 // (e.g. GUIs open a window, Ruby needs ruby installed, WASM needs a browser)
                 // we do `roc build` on them but don't run them.
@@ -1154,7 +1154,7 @@ fn run_with_wasmer(wasm_path: &std::path::Path, stdin: &[&str]) -> String {
     //        .unwrap();
 
     let store = Store::default();
-    let module = Module::from_file(&store, &wasm_path).unwrap();
+    let module = Module::from_file(&store, wasm_path).unwrap();
 
     let mut fake_stdin = wasmer_wasi::Pipe::new();
     let fake_stdout = wasmer_wasi::Pipe::new();
diff --git a/crates/compiler/build/src/link.rs b/crates/compiler/build/src/link.rs
index b37c235d77..a31669a34f 100644
--- a/crates/compiler/build/src/link.rs
+++ b/crates/compiler/build/src/link.rs
@@ -124,7 +124,7 @@ pub fn build_zig_host_native(
             bitcode::get_builtins_host_obj_path()
         };
 
-        zig_cmd.args(&[
+        zig_cmd.args([
             "build-exe",
             "-fPIE",
             "-rdynamic", // make sure roc_alloc and friends are exposed
@@ -132,10 +132,10 @@ pub fn build_zig_host_native(
             &builtins_obj,
         ]);
     } else {
-        zig_cmd.args(&["build-obj", "-fPIC"]);
+        zig_cmd.args(["build-obj", "-fPIC"]);
     }
 
-    zig_cmd.args(&[
+    zig_cmd.args([
         zig_host_src,
         &format!("-femit-bin={}", emit_bin),
         "--pkg-begin",
@@ -154,7 +154,7 @@ pub fn build_zig_host_native(
     // when we use zig 0.9. It looks like zig 0.10 is going to fix
     // this problem for us, so this is a temporary workaround
     if !target.contains("windows") {
-        zig_cmd.args(&[
+        zig_cmd.args([
             // include the zig runtime
             "-fcompiler-rt",
         ]);
@@ -162,13 +162,13 @@ pub fn build_zig_host_native(
 
     // valgrind does not yet support avx512 instructions, see #1963.
     if env::var("NO_AVX512").is_ok() {
-        zig_cmd.args(&["-mcpu", "x86_64"]);
+        zig_cmd.args(["-mcpu", "x86_64"]);
     }
 
     if matches!(opt_level, OptLevel::Optimize) {
-        zig_cmd.args(&["-O", "ReleaseSafe"]);
+        zig_cmd.args(["-O", "ReleaseSafe"]);
     } else if matches!(opt_level, OptLevel::Size) {
-        zig_cmd.args(&["-O", "ReleaseSmall"]);
+        zig_cmd.args(["-O", "ReleaseSmall"]);
     }
 
     zig_cmd
@@ -378,9 +378,9 @@ pub fn build_zig_host_wasm32(
         .args(args);
 
     if matches!(opt_level, OptLevel::Optimize) {
-        zig_cmd.args(&["-O", "ReleaseSafe"]);
+        zig_cmd.args(["-O", "ReleaseSafe"]);
     } else if matches!(opt_level, OptLevel::Size) {
-        zig_cmd.args(&["-O", "ReleaseSmall"]);
+        zig_cmd.args(["-O", "ReleaseSmall"]);
     }
 
     zig_cmd
@@ -400,11 +400,11 @@ pub fn build_c_host_native(
     let mut clang_cmd = clang();
     clang_cmd
         .env_clear()
-        .env("PATH", &env_path)
-        .env("CPATH", &env_cpath)
-        .env("HOME", &env_home)
+        .env("PATH", env_path)
+        .env("CPATH", env_cpath)
+        .env("HOME", env_home)
         .args(sources)
-        .args(&["-o", dest]);
+        .args(["-o", dest]);
     if let Some(shared_lib_path) = shared_lib_path {
         match target.operating_system {
             OperatingSystem::Windows => {
@@ -425,7 +425,7 @@ pub fn build_c_host_native(
                 );
             }
             _ => {
-                clang_cmd.args(&[
+                clang_cmd.args([
                     shared_lib_path.to_str().unwrap(),
                     // This line is commented out because
                     // @bhansconnect: With the addition of Str.graphemes, always
@@ -444,7 +444,7 @@ pub fn build_c_host_native(
             }
         }
     } else {
-        clang_cmd.args(&["-fPIC", "-c"]);
+        clang_cmd.args(["-fPIC", "-c"]);
     }
     if matches!(opt_level, OptLevel::Optimize) {
         clang_cmd.arg("-O3");
@@ -473,8 +473,8 @@ pub fn build_swift_host_native(
     let mut command = Command::new("arch");
     command
         .env_clear()
-        .env("PATH", &env_path)
-        .env("HOME", &env_home);
+        .env("PATH", env_path)
+        .env("HOME", env_home);
 
     match arch {
         Architecture::Aarch64(_) => command.arg("-arm64"),
@@ -487,10 +487,10 @@ pub fn build_swift_host_native(
         .args(sources)
         .arg("-emit-object")
         .arg("-parse-as-library")
-        .args(&["-o", dest]);
+        .args(["-o", dest]);
 
     if let Some(objc_header) = objc_header_path {
-        command.args(&["-import-objc-header", objc_header]);
+        command.args(["-import-objc-header", objc_header]);
     }
 
     if matches!(opt_level, OptLevel::Optimize) {
@@ -641,7 +641,7 @@ pub fn rebuild_host(
 
         let source_file = if shared_lib_path.is_some() {
             cargo_cmd.env("RUSTFLAGS", "-C link-dead-code");
-            cargo_cmd.args(&["--bin", "host"]);
+            cargo_cmd.args(["--bin", "host"]);
             "src/main.rs"
         } else {
             cargo_cmd.arg("--lib");
@@ -673,7 +673,7 @@ pub fn rebuild_host(
 
             let mut ld_cmd = Command::new("ld");
 
-            ld_cmd.env_clear().env("PATH", &env_path).args(&[
+            ld_cmd.env_clear().env("PATH", &env_path).args([
                 "-r",
                 "-L",
                 cargo_out_dir.to_str().unwrap(),
@@ -693,7 +693,7 @@ pub fn rebuild_host(
     } else if rust_host_src.exists() {
         // Compile and link host.rs, if it exists
         let mut rustc_cmd = Command::new("rustc");
-        rustc_cmd.args(&[
+        rustc_cmd.args([
             rust_host_src.to_str().unwrap(),
             "-o",
             rust_host_dest.to_str().unwrap(),
@@ -739,7 +739,7 @@ pub fn rebuild_host(
 
             let mut ld_cmd = Command::new("ld");
 
-            ld_cmd.env_clear().env("PATH", &env_path).args(&[
+            ld_cmd.env_clear().env("PATH", &env_path).args([
                 "-r",
                 c_host_dest.to_str().unwrap(),
                 rust_host_dest.to_str().unwrap(),
@@ -856,9 +856,9 @@ fn link_linux(
     if let Architecture::X86_32(_) = target.architecture {
         return Ok((
             zig()
-                .args(&["build-exe"])
+                .args(["build-exe"])
                 .args(input_paths)
-                .args(&[
+                .args([
                     "-target",
                     "i386-linux-musl",
                     "-lc",
@@ -1011,7 +1011,7 @@ fn link_linux(
                 .filter(|&(ref k, _)| k.starts_with("NIX_"))
                 .collect::<HashMap<String, String>>(),
         )
-        .args(&[
+        .args([
             "--gc-sections",
             "--eh-frame-hdr",
             "-A",
@@ -1021,11 +1021,11 @@ fn link_linux(
             &*crtn_path.to_string_lossy(),
         ])
         .args(&base_args)
-        .args(&["-dynamic-linker", ld_linux])
+        .args(["-dynamic-linker", ld_linux])
         .args(input_paths)
         // ld.lld requires this argument, and does not accept --arch
         // .args(&["-L/usr/lib/x86_64-linux-gnu"])
-        .args(&[
+        .args([
             // Libraries - see https://github.com/roc-lang/roc/pull/554#discussion_r496365925
             // for discussion and further references
             "-lc",
@@ -1076,7 +1076,7 @@ fn link_macos(
         // The `-l` flags should go after the `.o` arguments
         // Don't allow LD_ env vars to affect this
         .env_clear()
-        .args(&[
+        .args([
             // NOTE: we don't do --gc-sections on macOS because the default
             // macOS linker doesn't support it, but it's a performance
             // optimization, so if we ever switch to a different linker,
@@ -1108,7 +1108,7 @@ fn link_macos(
         ld_command.arg(roc_link_flag);
     }
 
-    ld_command.args(&[
+    ld_command.args([
         // Libraries - see https://github.com/roc-lang/roc/pull/554#discussion_r496392274
         // for discussion and further references
         "-lSystem",
@@ -1148,7 +1148,7 @@ fn link_macos(
         Architecture::Aarch64(_) => {
             ld_child.wait()?;
             let codesign_child = Command::new("codesign")
-                .args(&["-s", "-", output_path.to_str().unwrap()])
+                .args(["-s", "-", output_path.to_str().unwrap()])
                 .spawn()?;
 
             Ok((codesign_child, output_path))
@@ -1187,7 +1187,7 @@ fn link_wasm32(
     let child = zig()
         // .env_clear()
         // .env("PATH", &env_path)
-        .args(&["build-exe"])
+        .args(["build-exe"])
         .args(input_paths)
         .args([
             // include wasi libc
@@ -1222,7 +1222,7 @@ fn link_windows(
     match link_type {
         LinkType::Dylib => {
             let child = zig()
-                .args(&["build-lib"])
+                .args(["build-lib"])
                 .args(input_paths)
                 .args([
                     "-lc",
@@ -1244,7 +1244,7 @@ fn link_windows(
         }
         LinkType::Executable => {
             let child = zig()
-                .args(&["build-exe"])
+                .args(["build-exe"])
                 .args(input_paths)
                 .args([
                     "-target",
diff --git a/crates/compiler/build/src/program.rs b/crates/compiler/build/src/program.rs
index 50ddf387c0..99bb3d62fa 100644
--- a/crates/compiler/build/src/program.rs
+++ b/crates/compiler/build/src/program.rs
@@ -347,7 +347,7 @@ fn gen_from_mono_module_llvm(
 
         // run the debugir https://github.com/vaivaswatha/debugir tool
         match Command::new("debugir")
-            .args(&["-instnamer", app_ll_file.to_str().unwrap()])
+            .args(["-instnamer", app_ll_file.to_str().unwrap()])
             .output()
         {
             Ok(_) => {}
@@ -369,7 +369,7 @@ fn gen_from_mono_module_llvm(
             | Architecture::Aarch64(_)
             | Architecture::Wasm32 => {
                 let ll_to_bc = Command::new("llvm-as")
-                    .args(&[
+                    .args([
                         app_ll_dbg_file.to_str().unwrap(),
                         "-o",
                         app_bc_file.to_str().unwrap(),
diff --git a/crates/compiler/builtins/build.rs b/crates/compiler/builtins/build.rs
index 6b937fa18c..b72aa3673f 100644
--- a/crates/compiler/builtins/build.rs
+++ b/crates/compiler/builtins/build.rs
@@ -90,7 +90,7 @@ fn generate_object_file(bitcode_path: &Path, zig_object: &str, object_file_name:
         let mut zig_cmd = zig();
 
         zig_cmd
-            .current_dir(&bitcode_path)
+            .current_dir(bitcode_path)
             .args(["build", zig_object, "-Drelease=true"]);
 
         run_command(zig_cmd, 0);
@@ -126,7 +126,7 @@ fn generate_bc_file(bitcode_path: &Path, zig_object: &str, file_name: &str) {
     let mut zig_cmd = zig();
 
     zig_cmd
-        .current_dir(&bitcode_path)
+        .current_dir(bitcode_path)
         .args(["build", zig_object, "-Drelease=true"]);
 
     run_command(zig_cmd, 0);
@@ -168,7 +168,7 @@ fn copy_zig_builtins_to_target_dir(bitcode_path: &Path) {
 // recursively copy all the .zig files from this directory, but do *not* recurse into zig-cache/
 fn cp_unless_zig_cache(src_dir: &Path, target_dir: &Path) -> io::Result<()> {
     // Make sure the destination directory exists before we try to copy anything into it.
-    std::fs::create_dir_all(&target_dir).unwrap_or_else(|err| {
+    std::fs::create_dir_all(target_dir).unwrap_or_else(|err| {
         panic!(
             "Failed to create output library directory for zig bitcode {:?}: {:?}",
             target_dir, err
diff --git a/crates/compiler/builtins/roc/Dict.roc b/crates/compiler/builtins/roc/Dict.roc
index cb83d06b7c..e217f87e0d 100644
--- a/crates/compiler/builtins/roc/Dict.roc
+++ b/crates/compiler/builtins/roc/Dict.roc
@@ -223,18 +223,18 @@ expect update (single "a" Bool.true) "a" alterValue == empty
 ##         Dict.empty
 ##         |> Dict.insert 1234 "5678"
 ##         |> Dict.contains 1234
-##         |> Bool.isEq Bool.true
 contains : Dict k v, k -> Bool | k has Eq
 contains = \@Dict list, needle ->
-    step = \_, Pair key _val ->
-        if key == needle then
-            Break {}
-        else
-            Continue {}
+    List.any list \Pair key _val -> key == needle
 
-    when List.iterate list {} step is
-        Continue _ -> Bool.false
-        Break _ -> Bool.true
+expect contains empty "a" == Bool.false
+expect contains (single "a" {}) "a" == Bool.true
+expect contains (single "b" {}) "a" == Bool.false
+expect
+    Dict.empty
+    |> Dict.insert 1234 "5678"
+    |> Dict.contains 1234
+    |> Bool.isEq Bool.true
 
 ## Returns a dictionary containing the key and value provided as input.
 ##
diff --git a/crates/compiler/builtins/roc/List.roc b/crates/compiler/builtins/roc/List.roc
index 0e06253a22..e968d35712 100644
--- a/crates/compiler/builtins/roc/List.roc
+++ b/crates/compiler/builtins/roc/List.roc
@@ -8,7 +8,6 @@ interface List
         map,
         len,
         withCapacity,
-        iterate,
         walkBackwards,
         concat,
         first,
diff --git a/crates/compiler/can/src/abilities.rs b/crates/compiler/can/src/abilities.rs
index cab1a7d929..1dde05adab 100644
--- a/crates/compiler/can/src/abilities.rs
+++ b/crates/compiler/can/src/abilities.rs
@@ -28,7 +28,7 @@ pub struct MemberVariables {
 
 /// The member and its signature is defined locally, in the module the store is created for.
 /// We need to instantiate and introduce this during solving.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ResolvedMemberType(Variable);
 
 /// Member type information that needs to be resolved from imports.
@@ -56,7 +56,7 @@ impl ResolvePhase for Pending {
     type MemberType = PendingMemberType;
 }
 
-#[derive(Default, Debug, Clone, Copy, PartialEq)]
+#[derive(Default, Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Resolved;
 impl ResolvePhase for Resolved {
     type MemberType = ResolvedMemberType;
diff --git a/crates/compiler/can/src/def.rs b/crates/compiler/can/src/def.rs
index 20c648125b..24fba9813d 100644
--- a/crates/compiler/can/src/def.rs
+++ b/crates/compiler/can/src/def.rs
@@ -1821,7 +1821,7 @@ pub(crate) fn sort_can_defs(
                 .strongly_connected_components_subset(group);
 
             debug_assert!(
-                !group.iter_ones().any(|index| matches!((&defs[index]).as_ref().unwrap().loc_pattern.value, Pattern::AbilityMemberSpecialization{..})),
+                !group.iter_ones().any(|index| matches!(defs[index].as_ref().unwrap().loc_pattern.value, Pattern::AbilityMemberSpecialization{..})),
                 "A specialization is involved in a recursive cycle - this should not be knowable until solving");
 
             let declaration = if direct_sccs.groups().count() == 1 {
diff --git a/crates/compiler/can/src/expr.rs b/crates/compiler/can/src/expr.rs
index 4e7e9d13d4..fad9e313df 100644
--- a/crates/compiler/can/src/expr.rs
+++ b/crates/compiler/can/src/expr.rs
@@ -65,7 +65,7 @@ impl Output {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Copy)]
+#[derive(Clone, Debug, PartialEq, Eq, Copy)]
 pub enum IntValue {
     I128([u8; 16]),
     U128([u8; 16]),
@@ -345,7 +345,7 @@ pub struct ClosureData {
 ///
 /// We distinguish them from closures so we can have better error messages
 /// during constraint generation.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct AccessorData {
     pub name: Symbol,
     pub function_var: Variable,
@@ -485,7 +485,7 @@ pub struct Field {
     pub loc_expr: Box<Loc<Expr>>,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Recursive {
     NotRecursive = 0,
     Recursive = 1,
@@ -888,7 +888,7 @@ pub fn canonicalize_expr<'a>(
                         var_store,
                         inner_scope,
                         region,
-                        *branch,
+                        branch,
                         &mut output,
                     )
                 });
@@ -1493,7 +1493,7 @@ fn canonicalize_fields<'a>(
     let mut output = Output::default();
 
     for loc_field in fields.iter() {
-        match canonicalize_field(env, var_store, scope, &loc_field.value, loc_field.region) {
+        match canonicalize_field(env, var_store, scope, &loc_field.value) {
             Ok((label, field_expr, field_out, field_var)) => {
                 let field = Field {
                     var: field_var,
@@ -1546,7 +1546,6 @@ fn canonicalize_field<'a>(
     var_store: &mut VarStore,
     scope: &mut Scope,
     field: &'a ast::AssignedField<'a, ast::Expr<'a>>,
-    region: Region,
 ) -> Result<(Lowercase, Loc<Expr>, Output, Variable), CanonicalizeFieldProblem> {
     use roc_parse::ast::AssignedField::*;
 
@@ -1576,7 +1575,7 @@ fn canonicalize_field<'a>(
         }
 
         SpaceBefore(sub_field, _) | SpaceAfter(sub_field, _) => {
-            canonicalize_field(env, var_store, scope, sub_field, region)
+            canonicalize_field(env, var_store, scope, sub_field)
         }
 
         Malformed(_string) => {
@@ -1652,7 +1651,7 @@ fn canonicalize_var_lookup(
 }
 
 /// Currently uses the heuristic of "only inline if it's a builtin"
-pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) -> Expr {
+pub fn inline_calls(var_store: &mut VarStore, expr: Expr) -> Expr {
     use Expr::*;
 
     match expr {
@@ -1681,7 +1680,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
             let mut new_elems = Vec::with_capacity(loc_elems.len());
 
             for loc_elem in loc_elems {
-                let value = inline_calls(var_store, scope, loc_elem.value);
+                let value = inline_calls(var_store, loc_elem.value);
 
                 new_elems.push(Loc {
                     value,
@@ -1706,20 +1705,20 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
         } => {
             let loc_cond = Box::new(Loc {
                 region: loc_cond.region,
-                value: inline_calls(var_store, scope, loc_cond.value),
+                value: inline_calls(var_store, loc_cond.value),
             });
 
             let mut new_branches = Vec::with_capacity(branches.len());
 
             for branch in branches {
                 let value = Loc {
-                    value: inline_calls(var_store, scope, branch.value.value),
+                    value: inline_calls(var_store, branch.value.value),
                     region: branch.value.region,
                 };
                 let guard = match branch.guard {
                     Some(loc_expr) => Some(Loc {
                         region: loc_expr.region,
-                        value: inline_calls(var_store, scope, loc_expr.value),
+                        value: inline_calls(var_store, loc_expr.value),
                     }),
                     None => None,
                 };
@@ -1753,12 +1752,12 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
 
             for (loc_cond, loc_expr) in branches {
                 let loc_cond = Loc {
-                    value: inline_calls(var_store, scope, loc_cond.value),
+                    value: inline_calls(var_store, loc_cond.value),
                     region: loc_cond.region,
                 };
 
                 let loc_expr = Loc {
-                    value: inline_calls(var_store, scope, loc_expr.value),
+                    value: inline_calls(var_store, loc_expr.value),
                     region: loc_expr.region,
                 };
 
@@ -1767,7 +1766,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
 
             let final_else = Box::new(Loc {
                 region: final_else.region,
-                value: inline_calls(var_store, scope, final_else.value),
+                value: inline_calls(var_store, final_else.value),
             });
 
             If {
@@ -1785,12 +1784,12 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
         } => {
             let loc_condition = Loc {
                 region: loc_condition.region,
-                value: inline_calls(var_store, scope, loc_condition.value),
+                value: inline_calls(var_store, loc_condition.value),
             };
 
             let loc_continuation = Loc {
                 region: loc_continuation.region,
-                value: inline_calls(var_store, scope, loc_continuation.value),
+                value: inline_calls(var_store, loc_continuation.value),
             };
 
             Expect {
@@ -1807,12 +1806,12 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
         } => {
             let loc_condition = Loc {
                 region: loc_condition.region,
-                value: inline_calls(var_store, scope, loc_condition.value),
+                value: inline_calls(var_store, loc_condition.value),
             };
 
             let loc_continuation = Loc {
                 region: loc_continuation.region,
-                value: inline_calls(var_store, scope, loc_continuation.value),
+                value: inline_calls(var_store, loc_continuation.value),
             };
 
             ExpectFx {
@@ -1830,7 +1829,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
                     loc_pattern: def.loc_pattern,
                     loc_expr: Loc {
                         region: def.loc_expr.region,
-                        value: inline_calls(var_store, scope, def.loc_expr.value),
+                        value: inline_calls(var_store, def.loc_expr.value),
                     },
                     expr_var: def.expr_var,
                     pattern_vars: def.pattern_vars,
@@ -1840,7 +1839,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
 
             let loc_expr = Loc {
                 region: loc_expr.region,
-                value: inline_calls(var_store, scope, loc_expr.value),
+                value: inline_calls(var_store, loc_expr.value),
             };
 
             LetRec(new_defs, Box::new(loc_expr), mark)
@@ -1851,7 +1850,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
                 loc_pattern: def.loc_pattern,
                 loc_expr: Loc {
                     region: def.loc_expr.region,
-                    value: inline_calls(var_store, scope, def.loc_expr.value),
+                    value: inline_calls(var_store, def.loc_expr.value),
                 },
                 expr_var: def.expr_var,
                 pattern_vars: def.pattern_vars,
@@ -1860,7 +1859,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
 
             let loc_expr = Loc {
                 region: loc_expr.region,
-                value: inline_calls(var_store, scope, loc_expr.value),
+                value: inline_calls(var_store, loc_expr.value),
             };
 
             LetNonRec(Box::new(def), Box::new(loc_expr))
@@ -1878,7 +1877,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
         }) => {
             let loc_expr = *loc_body;
             let loc_expr = Loc {
-                value: inline_calls(var_store, scope, loc_expr.value),
+                value: inline_calls(var_store, loc_expr.value),
                 region: loc_expr.region,
             };
 
@@ -1938,7 +1937,7 @@ pub fn inline_calls(var_store: &mut VarStore, scope: &mut Scope, expr: Expr) ->
             let (var, loc_expr) = *argument;
             let argument = Box::new((
                 var,
-                loc_expr.map_owned(|expr| inline_calls(var_store, scope, expr)),
+                loc_expr.map_owned(|expr| inline_calls(var_store, expr)),
             ));
 
             OpaqueRef {
@@ -2737,7 +2736,7 @@ fn get_lookup_symbols(expr: &Expr) -> Vec<ExpectLookup> {
             | Expr::ExpectFx {
                 loc_continuation, ..
             } => {
-                stack.push(&(*loc_continuation).value);
+                stack.push(&loc_continuation.value);
 
                 // Intentionally ignore the lookups in the nested `expect` condition itself,
                 // because they couldn't possibly influence the outcome of this `expect`!
diff --git a/crates/compiler/can/src/operator.rs b/crates/compiler/can/src/operator.rs
index 9a46592f0a..fac3cf2b37 100644
--- a/crates/compiler/can/src/operator.rs
+++ b/crates/compiler/can/src/operator.rs
@@ -79,7 +79,7 @@ fn desugar_value_def<'a>(arena: &'a Bump, def: &'a ValueDef<'a>) -> ValueDef<'a>
             ann_pattern,
             ann_type,
             comment: *comment,
-            body_pattern: *body_pattern,
+            body_pattern,
             body_expr: desugar_expr(arena, body_expr),
         },
         Expect {
diff --git a/crates/compiler/collections/src/vec_set.rs b/crates/compiler/collections/src/vec_set.rs
index d5fd02a63c..8415bbc102 100644
--- a/crates/compiler/collections/src/vec_set.rs
+++ b/crates/compiler/collections/src/vec_set.rs
@@ -1,6 +1,6 @@
 use std::{borrow::Borrow, iter::FromIterator};
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct VecSet<T> {
     elements: Vec<T>,
 }
diff --git a/crates/compiler/derive/src/lib.rs b/crates/compiler/derive/src/lib.rs
index 1f63ac3734..43d547ddb5 100644
--- a/crates/compiler/derive/src/lib.rs
+++ b/crates/compiler/derive/src/lib.rs
@@ -99,14 +99,11 @@ impl DerivedModule {
         exposed_by_module: &ExposedByModule,
         key: DeriveKey,
     ) -> &(Symbol, Def, SpecializationLambdaSets) {
-        match self.map.get(&key) {
-            Some(entry) => {
-                // rustc won't let us return an immutable reference *and* continue using
-                // `self.map` immutably below, but this is safe, because we are not returning
-                // an immutable reference to the entry.
-                return unsafe { std::mem::transmute(entry) };
-            }
-            None => {}
+        if let Some(entry) = self.map.get(&key) {
+            // rustc won't let us return an immutable reference *and* continue using
+            // `self.map` immutably below, but this is safe, because we are not returning
+            // an immutable reference to the entry.
+            return unsafe { std::mem::transmute(entry) };
         }
 
         let ident_id = if cfg!(debug_assertions) || cfg!(feature = "debug-derived-symbols") {
diff --git a/crates/compiler/derive_key/src/lib.rs b/crates/compiler/derive_key/src/lib.rs
index 65a0062a7d..a994a622e3 100644
--- a/crates/compiler/derive_key/src/lib.rs
+++ b/crates/compiler/derive_key/src/lib.rs
@@ -25,7 +25,7 @@ use hash::{FlatHash, FlatHashKey};
 use roc_module::symbol::Symbol;
 use roc_types::subs::{Subs, Variable};
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum DeriveError {
     /// Unbound variable present in the type-to-derive. It may be possible to derive for this type
     /// once the unbound variable is resolved.
diff --git a/crates/compiler/fmt/src/annotation.rs b/crates/compiler/fmt/src/annotation.rs
index 9fcdb4bf12..e3cd669f67 100644
--- a/crates/compiler/fmt/src/annotation.rs
+++ b/crates/compiler/fmt/src/annotation.rs
@@ -166,8 +166,8 @@ impl<'a> Formattable for TypeAnnotation<'a> {
 
             Wildcard | Inferred | BoundVariable(_) | Malformed(_) => false,
             Function(args, result) => {
-                (&result.value).is_multiline()
-                    || args.iter().any(|loc_arg| (&loc_arg.value).is_multiline())
+                result.value.is_multiline()
+                    || args.iter().any(|loc_arg| loc_arg.value.is_multiline())
             }
             Apply(_, _, args) => args.iter().any(|loc_arg| loc_arg.value.is_multiline()),
             As(lhs, _, _) => lhs.value.is_multiline(),
@@ -226,7 +226,7 @@ impl<'a> Formattable for TypeAnnotation<'a> {
                         buf.newline();
                     }
 
-                    (&argument.value).format_with_options(
+                    argument.value.format_with_options(
                         buf,
                         Parens::InFunctionType,
                         Newlines::No,
@@ -251,7 +251,8 @@ impl<'a> Formattable for TypeAnnotation<'a> {
                 buf.push_str("->");
                 buf.spaces(1);
 
-                (&ret.value).format_with_options(buf, Parens::InFunctionType, Newlines::No, indent);
+                ret.value
+                    .format_with_options(buf, Parens::InFunctionType, Newlines::No, indent);
 
                 if needs_parens {
                     buf.push(')')
@@ -275,12 +276,9 @@ impl<'a> Formattable for TypeAnnotation<'a> {
 
                 for argument in *arguments {
                     buf.spaces(1);
-                    (&argument.value).format_with_options(
-                        buf,
-                        Parens::InApply,
-                        Newlines::No,
-                        indent,
-                    );
+                    argument
+                        .value
+                        .format_with_options(buf, Parens::InApply, Newlines::No, indent);
                 }
 
                 if write_parens {
@@ -371,12 +369,12 @@ impl<'a> Formattable for AssignedField<'a, TypeAnnotation<'a>> {
     fn format_with_options<'buf>(
         &self,
         buf: &mut Buf<'buf>,
-        parens: Parens,
+        _parens: Parens,
         newlines: Newlines,
         indent: u16,
     ) {
         // we abuse the `Newlines` type to decide between multiline or single-line layout
-        format_assigned_field_help(self, buf, parens, indent, 1, newlines == Newlines::Yes);
+        format_assigned_field_help(self, buf, indent, 1, newlines == Newlines::Yes);
     }
 }
 
@@ -388,12 +386,12 @@ impl<'a> Formattable for AssignedField<'a, Expr<'a>> {
     fn format_with_options<'buf>(
         &self,
         buf: &mut Buf<'buf>,
-        parens: Parens,
+        _parens: Parens,
         newlines: Newlines,
         indent: u16,
     ) {
         // we abuse the `Newlines` type to decide between multiline or single-line layout
-        format_assigned_field_help(self, buf, parens, indent, 0, newlines == Newlines::Yes);
+        format_assigned_field_help(self, buf, indent, 0, newlines == Newlines::Yes);
     }
 }
 
@@ -413,7 +411,6 @@ fn is_multiline_assigned_field_help<T: Formattable>(afield: &AssignedField<'_, T
 fn format_assigned_field_help<'a, 'buf, T>(
     zelf: &AssignedField<'a, T>,
     buf: &mut Buf<'buf>,
-    parens: Parens,
     indent: u16,
     separator_spaces: usize,
     is_multiline: bool,
@@ -466,24 +463,10 @@ fn format_assigned_field_help<'a, 'buf, T>(
         }
         AssignedField::SpaceBefore(sub_field, spaces) => {
             fmt_comments_only(buf, spaces.iter(), NewlineAt::Bottom, indent);
-            format_assigned_field_help(
-                sub_field,
-                buf,
-                parens,
-                indent,
-                separator_spaces,
-                is_multiline,
-            );
+            format_assigned_field_help(sub_field, buf, indent, separator_spaces, is_multiline);
         }
         AssignedField::SpaceAfter(sub_field, spaces) => {
-            format_assigned_field_help(
-                sub_field,
-                buf,
-                parens,
-                indent,
-                separator_spaces,
-                is_multiline,
-            );
+            format_assigned_field_help(sub_field, buf, indent, separator_spaces, is_multiline);
             fmt_comments_only(buf, spaces.iter(), NewlineAt::Bottom, indent);
         }
         Malformed(raw) => {
@@ -497,7 +480,7 @@ impl<'a> Formattable for Tag<'a> {
         use self::Tag::*;
 
         match self {
-            Apply { args, .. } => args.iter().any(|arg| (&arg.value).is_multiline()),
+            Apply { args, .. } => args.iter().any(|arg| arg.value.is_multiline()),
             Tag::SpaceBefore(_, _) | Tag::SpaceAfter(_, _) => true,
             Malformed(text) => text.chars().any(|c| c == '\n'),
         }
diff --git a/crates/compiler/fmt/src/expr.rs b/crates/compiler/fmt/src/expr.rs
index f5395e6d24..6cb1709863 100644
--- a/crates/compiler/fmt/src/expr.rs
+++ b/crates/compiler/fmt/src/expr.rs
@@ -542,7 +542,7 @@ fn fmt_binops<'a, 'buf>(
     indent: u16,
 ) {
     let is_multiline = part_of_multi_line_binops
-        || (&loc_right_side.value).is_multiline()
+        || loc_right_side.value.is_multiline()
         || lefts.iter().any(|(expr, _)| expr.value.is_multiline());
 
     for (loc_left_side, loc_binop) in lefts {
@@ -1045,7 +1045,7 @@ fn fmt_closure<'a, 'buf>(
 
     buf.push_str("->");
 
-    let is_multiline = (&loc_ret.value).is_multiline();
+    let is_multiline = loc_ret.value.is_multiline();
 
     // If the body is multiline, go down a line and indent.
     let body_indent = if is_multiline {
@@ -1156,7 +1156,7 @@ fn fmt_backpassing<'a, 'buf>(
 
     buf.push_str("<-");
 
-    let is_multiline = (&loc_ret.value).is_multiline();
+    let is_multiline = loc_ret.value.is_multiline();
 
     // If the body is multiline, go down a line and indent.
     let body_indent = if is_multiline {
diff --git a/crates/compiler/gen_dev/src/generic64/disassembler_test_macro.rs b/crates/compiler/gen_dev/src/generic64/disassembler_test_macro.rs
index f6af4bd81a..5461c54fd0 100644
--- a/crates/compiler/gen_dev/src/generic64/disassembler_test_macro.rs
+++ b/crates/compiler/gen_dev/src/generic64/disassembler_test_macro.rs
@@ -19,7 +19,7 @@ macro_rules! disassembler_test {
     // TODO: Not sure if there is a better way to merge these together,
     // but I like the end use of this a lot better than the old tests.
     ($assemble_fn: expr, $format_fn: expr) => {{
-        use crate::generic64::disassembler_test_macro::merge_instructions_without_line_numbers;
+        use $crate::generic64::disassembler_test_macro::merge_instructions_without_line_numbers;
         let arena = bumpalo::Bump::new();
         let (mut buf, cs) = setup_capstone_and_arena(&arena);
         $assemble_fn(&mut buf);
diff --git a/crates/compiler/gen_dev/src/generic64/x86_64.rs b/crates/compiler/gen_dev/src/generic64/x86_64.rs
index fce88a8178..37ee037557 100644
--- a/crates/compiler/gen_dev/src/generic64/x86_64.rs
+++ b/crates/compiler/gen_dev/src/generic64/x86_64.rs
@@ -1011,7 +1011,7 @@ impl Assembler<X86_64GeneralReg, X86_64FloatReg> for X86_64Assembler {
 
     #[inline(always)]
     fn call(buf: &mut Vec<'_, u8>, relocs: &mut Vec<'_, Relocation>, fn_name: String) {
-        buf.extend(&[0xE8, 0x00, 0x00, 0x00, 0x00]);
+        buf.extend([0xE8, 0x00, 0x00, 0x00, 0x00]);
         relocs.push(Relocation::LinkedFunction {
             offset: buf.len() as u64 - 4,
             name: fn_name,
@@ -1478,7 +1478,7 @@ fn binop_reg64_reg64(
     let rex = add_reg_extension(src, rex);
     let dst_mod = dst as u8 % 8;
     let src_mod = (src as u8 % 8) << 3;
-    buf.extend(&[rex, op_code, 0xC0 | dst_mod | src_mod]);
+    buf.extend([rex, op_code, 0xC0 | dst_mod | src_mod]);
 }
 
 #[inline(always)]
@@ -1493,7 +1493,7 @@ fn extended_binop_reg64_reg64(
     let rex = add_reg_extension(src, rex);
     let dst_mod = dst as u8 % 8;
     let src_mod = (src as u8 % 8) << 3;
-    buf.extend(&[rex, op_code1, op_code2, 0xC0 | dst_mod | src_mod]);
+    buf.extend([rex, op_code1, op_code2, 0xC0 | dst_mod | src_mod]);
 }
 
 // Below here are the functions for all of the assembly instructions.
@@ -1508,8 +1508,8 @@ fn add_reg64_imm32(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, imm: i32) {
     let rex = add_rm_extension(dst, REX_W);
     let dst_mod = dst as u8 % 8;
     buf.reserve(7);
-    buf.extend(&[rex, 0x81, 0xC0 | dst_mod]);
-    buf.extend(&imm.to_le_bytes());
+    buf.extend([rex, 0x81, 0xC0 | dst_mod]);
+    buf.extend(imm.to_le_bytes());
 }
 
 /// `ADD r/m64,r64` -> Add r64 to r/m64.
@@ -1547,7 +1547,7 @@ fn addsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF2,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1555,7 +1555,7 @@ fn addsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF2, 0x0F, 0x58, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF2, 0x0F, 0x58, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1567,7 +1567,7 @@ fn addss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF3,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1575,7 +1575,7 @@ fn addss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF3, 0x0F, 0x58, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF3, 0x0F, 0x58, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1587,7 +1587,7 @@ fn mulsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF2,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1595,7 +1595,7 @@ fn mulsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF2, 0x0F, 0x59, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF2, 0x0F, 0x59, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1607,7 +1607,7 @@ fn divss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF3,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1615,7 +1615,7 @@ fn divss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF3, 0x0F, 0x5E, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF3, 0x0F, 0x5E, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1627,7 +1627,7 @@ fn divsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF2,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1635,7 +1635,7 @@ fn divsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF2, 0x0F, 0x5E, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF2, 0x0F, 0x5E, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1647,7 +1647,7 @@ fn mulss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF3,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1655,7 +1655,7 @@ fn mulss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF3, 0x0F, 0x59, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF3, 0x0F, 0x59, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1667,7 +1667,7 @@ fn andpd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
     let src_mod = src as u8 % 8;
 
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0x66,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1675,7 +1675,7 @@ fn andpd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0x66, 0x0F, 0x54, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0x66, 0x0F, 0x54, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1684,7 +1684,7 @@ fn andpd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_64Fl
 fn and_reg64_imm8(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, imm: i8) {
     let rex = add_rm_extension(dst, REX_W);
     let dst_mod = dst as u8 % 8;
-    buf.extend(&[rex, 0x83, 0xE0 | dst_mod, imm as u8]);
+    buf.extend([rex, 0x83, 0xE0 | dst_mod, imm as u8]);
 }
 
 /// `CMOVL r64,r/m64` -> Move if less (SF≠ OF).
@@ -1694,7 +1694,7 @@ fn cmovl_reg64_reg64(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, src: X86_64Ge
     let rex = add_rm_extension(src, rex);
     let dst_mod = (dst as u8 % 8) << 3;
     let src_mod = src as u8 % 8;
-    buf.extend(&[rex, 0x0F, 0x4C, 0xC0 | dst_mod | src_mod]);
+    buf.extend([rex, 0x0F, 0x4C, 0xC0 | dst_mod | src_mod]);
 }
 
 /// `CMP r/m64,i32` -> Compare i32 to r/m64.
@@ -1703,8 +1703,8 @@ fn cmp_reg64_imm32(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, imm: i32) {
     let rex = add_rm_extension(dst, REX_W);
     let dst_mod = dst as u8 % 8;
     buf.reserve(7);
-    buf.extend(&[rex, 0x81, 0xF8 | dst_mod]);
-    buf.extend(&imm.to_le_bytes());
+    buf.extend([rex, 0x81, 0xF8 | dst_mod]);
+    buf.extend(imm.to_le_bytes());
 }
 
 /// `CMP r/m64,r64` -> Compare r64 to r/m64.
@@ -1738,7 +1738,7 @@ fn mul_reg64_reg64(buf: &mut Vec<'_, u8>, src: X86_64GeneralReg) {
         rex |= REX_PREFIX_B;
     }
 
-    buf.extend(&[rex, 0xF7, 0b1110_0000 | (src as u8 % 8)]);
+    buf.extend([rex, 0xF7, 0b1110_0000 | (src as u8 % 8)]);
 }
 
 /// `IDIV r/m64` -> Signed divide RDX:RAX by r/m64, with result stored in RAX ← Quotient, RDX ← Remainder.
@@ -1756,9 +1756,9 @@ fn idiv_reg64_reg64(buf: &mut Vec<'_, u8>, src: X86_64GeneralReg) {
     //
     // The CQO instruction (available in 64-bit mode only) copies the sign (bit 63)
     // of the value in the RAX register into every bit position in the RDX register
-    buf.extend(&[0x48, 0x99]);
+    buf.extend([0x48, 0x99]);
 
-    buf.extend(&[rex, 0xF7, 0b1111_1000 | (src as u8 % 8)]);
+    buf.extend([rex, 0xF7, 0b1111_1000 | (src as u8 % 8)]);
 }
 
 /// `DIV r/m64` -> Unsigned divide RDX:RAX by r/m64, with result stored in RAX ← Quotient, RDX ← Remainder.
@@ -1776,10 +1776,10 @@ fn udiv_reg64_reg64(buf: &mut Vec<'_, u8>, src: X86_64GeneralReg) {
     //
     // The CQO instruction (available in 64-bit mode only) copies the sign (bit 63)
     // of the value in the RAX register into every bit position in the RDX register
-    buf.extend(&[0x48, 0x99]);
+    buf.extend([0x48, 0x99]);
 
     // adds a cqo (convert doubleword to quadword)
-    buf.extend(&[rex, 0xF7, 0b1111_0000 | (src as u8 % 8)]);
+    buf.extend([rex, 0xF7, 0b1111_0000 | (src as u8 % 8)]);
 }
 
 /// Jump near, relative, RIP = RIP + 32-bit displacement sign extended to 64-bits.
@@ -1787,7 +1787,7 @@ fn udiv_reg64_reg64(buf: &mut Vec<'_, u8>, src: X86_64GeneralReg) {
 fn jmp_imm32(buf: &mut Vec<'_, u8>, imm: i32) {
     buf.reserve(5);
     buf.push(0xE9);
-    buf.extend(&imm.to_le_bytes());
+    buf.extend(imm.to_le_bytes());
 }
 
 /// Jump near if not equal (ZF=0).
@@ -1796,7 +1796,7 @@ fn jne_imm32(buf: &mut Vec<'_, u8>, imm: i32) {
     buf.reserve(6);
     buf.push(0x0F);
     buf.push(0x85);
-    buf.extend(&imm.to_le_bytes());
+    buf.extend(imm.to_le_bytes());
 }
 
 /// `MOV r/m64, imm32` -> Move imm32 sign extended to 64-bits to r/m64.
@@ -1805,8 +1805,8 @@ fn mov_reg64_imm32(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, imm: i32) {
     let rex = add_rm_extension(dst, REX_W);
     let dst_mod = dst as u8 % 8;
     buf.reserve(7);
-    buf.extend(&[rex, 0xC7, 0xC0 | dst_mod]);
-    buf.extend(&imm.to_le_bytes());
+    buf.extend([rex, 0xC7, 0xC0 | dst_mod]);
+    buf.extend(imm.to_le_bytes());
 }
 
 /// `MOV r64, imm64` -> Move imm64 to r64.
@@ -1818,8 +1818,8 @@ fn mov_reg64_imm64(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, imm: i64) {
         let rex = add_opcode_extension(dst, REX_W);
         let dst_mod = dst as u8 % 8;
         buf.reserve(10);
-        buf.extend(&[rex, 0xB8 | dst_mod]);
-        buf.extend(&imm.to_le_bytes());
+        buf.extend([rex, 0xB8 | dst_mod]);
+        buf.extend(imm.to_le_bytes());
     }
 }
 
@@ -1854,12 +1854,12 @@ fn mov_base64_offset32_reg64(
     let src_mod = (src as u8 % 8) << 3;
     let base_mod = base as u8 % 8;
     buf.reserve(8);
-    buf.extend(&[rex, 0x89, 0x80 | src_mod | base_mod]);
+    buf.extend([rex, 0x89, 0x80 | src_mod | base_mod]);
     // Using RSP or R12 requires a secondary index byte.
     if base == X86_64GeneralReg::RSP || base == X86_64GeneralReg::R12 {
         buf.push(0x24);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 /// `MOV r64,r/m64` -> Move r/m64 to r64, where m64 references a base + offset.
@@ -1875,12 +1875,12 @@ fn mov_reg64_base64_offset32(
     let dst_mod = (dst as u8 % 8) << 3;
     let base_mod = base as u8 % 8;
     buf.reserve(8);
-    buf.extend(&[rex, 0x8B, 0x80 | dst_mod | base_mod]);
+    buf.extend([rex, 0x8B, 0x80 | dst_mod | base_mod]);
     // Using RSP or R12 requires a secondary index byte.
     if base == X86_64GeneralReg::RSP || base == X86_64GeneralReg::R12 {
         buf.push(0x24);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 /// `MOVZX r64,r/m8` -> Move r/m8 with zero extention to r64, where m8 references a base + offset.
@@ -1896,12 +1896,12 @@ fn movzx_reg64_base8_offset32(
     let dst_mod = (dst as u8 % 8) << 3;
     let base_mod = base as u8 % 8;
     buf.reserve(9);
-    buf.extend(&[rex, 0x0F, 0xB6, 0x80 | dst_mod | base_mod]);
+    buf.extend([rex, 0x0F, 0xB6, 0x80 | dst_mod | base_mod]);
     // Using RSP or R12 requires a secondary index byte.
     if base == X86_64GeneralReg::RSP || base == X86_64GeneralReg::R12 {
         buf.push(0x24);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 /// `MOVSD xmm1,xmm2` -> Move scalar double-precision floating-point value from xmm2 to xmm1 register.
@@ -1922,7 +1922,7 @@ fn raw_movsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF2,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1930,7 +1930,7 @@ fn raw_movsd_freg64_freg64(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF2, 0x0F, 0x10, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF2, 0x0F, 0x10, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1952,7 +1952,7 @@ fn raw_movss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_
     let src_high = src as u8 > 7;
     let src_mod = src as u8 % 8;
     if dst_high || src_high {
-        buf.extend(&[
+        buf.extend([
             0xF3,
             0x40 | ((dst_high as u8) << 2) | (src_high as u8),
             0x0F,
@@ -1960,7 +1960,7 @@ fn raw_movss_freg32_freg32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, src: X86_
             0xC0 | (dst_mod << 3) | (src_mod),
         ])
     } else {
-        buf.extend(&[0xF3, 0x0F, 0x10, 0xC0 | (dst_mod << 3) | (src_mod)])
+        buf.extend([0xF3, 0x0F, 0x10, 0xC0 | (dst_mod << 3) | (src_mod)])
     }
 }
 
@@ -1970,12 +1970,12 @@ fn movss_freg32_rip_offset32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, offset:
     let dst_mod = dst as u8 % 8;
     if dst as u8 > 7 {
         buf.reserve(9);
-        buf.extend(&[0xF3, 0x44, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
+        buf.extend([0xF3, 0x44, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
     } else {
         buf.reserve(8);
-        buf.extend(&[0xF3, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
+        buf.extend([0xF3, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 // `MOVSD xmm, m64` -> Load scalar double-precision floating-point value from m64 to xmm register.
@@ -1984,12 +1984,12 @@ fn movsd_freg64_rip_offset32(buf: &mut Vec<'_, u8>, dst: X86_64FloatReg, offset:
     let dst_mod = dst as u8 % 8;
     if dst as u8 > 7 {
         buf.reserve(9);
-        buf.extend(&[0xF2, 0x44, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
+        buf.extend([0xF2, 0x44, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
     } else {
         buf.reserve(8);
-        buf.extend(&[0xF2, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
+        buf.extend([0xF2, 0x0F, 0x10, 0x05 | (dst_mod << 3)]);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 /// `MOVSD r/m64,xmm1` -> Move xmm1 to r/m64. where m64 references the base pointer.
@@ -2009,12 +2009,12 @@ fn movsd_base64_offset32_freg64(
     if src as u8 > 7 || base as u8 > 7 {
         buf.push(rex);
     }
-    buf.extend(&[0x0F, 0x11, 0x80 | src_mod | base_mod]);
+    buf.extend([0x0F, 0x11, 0x80 | src_mod | base_mod]);
     // Using RSP or R12 requires a secondary index byte.
     if base == X86_64GeneralReg::RSP || base == X86_64GeneralReg::R12 {
         buf.push(0x24);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 /// `MOVSD xmm1,r/m64` -> Move r/m64 to xmm1. where m64 references the base pointer.
@@ -2034,12 +2034,12 @@ fn movsd_freg64_base64_offset32(
     if dst as u8 > 7 || base as u8 > 7 {
         buf.push(rex);
     }
-    buf.extend(&[0x0F, 0x10, 0x80 | dst_mod | base_mod]);
+    buf.extend([0x0F, 0x10, 0x80 | dst_mod | base_mod]);
     // Using RSP or R12 requires a secondary index byte.
     if base == X86_64GeneralReg::RSP || base == X86_64GeneralReg::R12 {
         buf.push(0x24);
     }
-    buf.extend(&offset.to_le_bytes());
+    buf.extend(offset.to_le_bytes());
 }
 
 /// `NEG r/m64` -> Two's complement negate r/m64.
@@ -2047,7 +2047,7 @@ fn movsd_freg64_base64_offset32(
 fn neg_reg64(buf: &mut Vec<'_, u8>, reg: X86_64GeneralReg) {
     let rex = add_rm_extension(reg, REX_W);
     let reg_mod = reg as u8 % 8;
-    buf.extend(&[rex, 0xF7, 0xD8 | reg_mod]);
+    buf.extend([rex, 0xF7, 0xD8 | reg_mod]);
 }
 
 // helper function for `set*` instructions
@@ -2060,10 +2060,10 @@ fn set_reg64_help(op_code: u8, buf: &mut Vec<'_, u8>, reg: X86_64GeneralReg) {
     let reg_mod = reg as u8 % 8;
     use X86_64GeneralReg::*;
     match reg {
-        RAX | RCX | RDX | RBX => buf.extend(&[0x0F, op_code, 0xC0 | reg_mod]),
-        RSP | RBP | RSI | RDI => buf.extend(&[REX, 0x0F, op_code, 0xC0 | reg_mod]),
+        RAX | RCX | RDX | RBX => buf.extend([0x0F, op_code, 0xC0 | reg_mod]),
+        RSP | RBP | RSI | RDI => buf.extend([REX, 0x0F, op_code, 0xC0 | reg_mod]),
         R8 | R9 | R10 | R11 | R12 | R13 | R14 | R15 => {
-            buf.extend(&[REX | 1, 0x0F, op_code, 0xC0 | reg_mod])
+            buf.extend([REX | 1, 0x0F, op_code, 0xC0 | reg_mod])
         }
     }
 
@@ -2085,7 +2085,7 @@ fn cvtsi2_help<T: RegTrait, U: RegTrait>(
     let mod1 = (dst.value() % 8) << 3;
     let mod2 = src.value() % 8;
 
-    buf.extend(&[op_code1, rex, 0x0F, op_code2, 0xC0 | mod1 | mod2])
+    buf.extend([op_code1, rex, 0x0F, op_code2, 0xC0 | mod1 | mod2])
 }
 
 #[inline(always)]
@@ -2099,7 +2099,7 @@ fn cvtsx2_help<T: RegTrait, V: RegTrait>(
     let mod1 = (dst.value() % 8) << 3;
     let mod2 = src.value() % 8;
 
-    buf.extend(&[op_code1, 0x0F, op_code2, 0xC0 | mod1 | mod2])
+    buf.extend([op_code1, 0x0F, op_code2, 0xC0 | mod1 | mod2])
 }
 
 /// `SETE r/m64` -> Set Byte on Condition - zero/equal (ZF=1)
@@ -2183,8 +2183,8 @@ fn sub_reg64_imm32(buf: &mut Vec<'_, u8>, dst: X86_64GeneralReg, imm: i32) {
     let rex = add_rm_extension(dst, REX_W);
     let dst_mod = dst as u8 % 8;
     buf.reserve(7);
-    buf.extend(&[rex, 0x81, 0xE8 | dst_mod]);
-    buf.extend(&imm.to_le_bytes());
+    buf.extend([rex, 0x81, 0xE8 | dst_mod]);
+    buf.extend(imm.to_le_bytes());
 }
 
 /// `SUB r/m64,r64` -> Sub r64 to r/m64.
@@ -2199,7 +2199,7 @@ fn pop_reg64(buf: &mut Vec<'_, u8>, reg: X86_64GeneralReg) {
     let reg_mod = reg as u8 % 8;
     if reg as u8 > 7 {
         let rex = add_opcode_extension(reg, REX);
-        buf.extend(&[rex, 0x58 | reg_mod]);
+        buf.extend([rex, 0x58 | reg_mod]);
     } else {
         buf.push(0x58 | reg_mod);
     }
@@ -2211,7 +2211,7 @@ fn push_reg64(buf: &mut Vec<'_, u8>, reg: X86_64GeneralReg) {
     let reg_mod = reg as u8 % 8;
     if reg as u8 > 7 {
         let rex = add_opcode_extension(reg, REX);
-        buf.extend(&[rex, 0x50 | reg_mod]);
+        buf.extend([rex, 0x50 | reg_mod]);
     } else {
         buf.push(0x50 | reg_mod);
     }
diff --git a/crates/compiler/gen_dev/src/lib.rs b/crates/compiler/gen_dev/src/lib.rs
index caef1c4ead..a8147cdab7 100644
--- a/crates/compiler/gen_dev/src/lib.rs
+++ b/crates/compiler/gen_dev/src/lib.rs
@@ -159,7 +159,7 @@ trait Backend<'a> {
                     let module_id = env.module_id;
                     let ident_ids = interns.all_ident_ids.get_mut(&module_id).unwrap();
 
-                    rc_proc_gen.expand_refcount_stmt(ident_ids, layout, modify, *following)
+                    rc_proc_gen.expand_refcount_stmt(ident_ids, layout, modify, following)
                 };
 
                 for spec in new_specializations.into_iter() {
diff --git a/crates/compiler/gen_dev/src/object_builder.rs b/crates/compiler/gen_dev/src/object_builder.rs
index 85cb925361..51b90f7735 100644
--- a/crates/compiler/gen_dev/src/object_builder.rs
+++ b/crates/compiler/gen_dev/src/object_builder.rs
@@ -421,7 +421,7 @@ fn build_proc<'a, B: Backend<'a>>(
             }
             Relocation::LinkedFunction { offset, name } => {
                 // If the symbol is an undefined roc function, we need to add it here.
-                if output.symbol_id(name.as_bytes()) == None && name.starts_with("roc_") {
+                if output.symbol_id(name.as_bytes()).is_none() && name.starts_with("roc_") {
                     let builtin_symbol = Symbol {
                         name: name.as_bytes().to_vec(),
                         value: 0,
@@ -435,7 +435,7 @@ fn build_proc<'a, B: Backend<'a>>(
                     output.add_symbol(builtin_symbol);
                 }
                 // If the symbol is an undefined reference counting procedure, we need to add it here.
-                if output.symbol_id(name.as_bytes()) == None {
+                if output.symbol_id(name.as_bytes()).is_none() {
                     for (sym, rc_name) in rc_proc_names.iter() {
                         if name == rc_name {
                             let section_id = output.add_section(
diff --git a/crates/compiler/gen_llvm/src/llvm/bitcode.rs b/crates/compiler/gen_llvm/src/llvm/bitcode.rs
index 686fa688bf..21183dae66 100644
--- a/crates/compiler/gen_llvm/src/llvm/bitcode.rs
+++ b/crates/compiler/gen_llvm/src/llvm/bitcode.rs
@@ -411,16 +411,16 @@ fn build_rc_wrapper<'a, 'ctx, 'env>(
             match rc_operation {
                 Mode::Inc => {
                     let n = 1;
-                    increment_refcount_layout(env, function_value, layout_ids, n, value, layout);
+                    increment_refcount_layout(env, layout_ids, n, value, layout);
                 }
                 Mode::IncN => {
                     let n = it.next().unwrap().into_int_value();
                     n.set_name(Symbol::ARG_2.as_str(&env.interns));
 
-                    increment_n_refcount_layout(env, function_value, layout_ids, n, value, layout);
+                    increment_n_refcount_layout(env, layout_ids, n, value, layout);
                 }
                 Mode::Dec => {
-                    decrement_refcount_layout(env, function_value, layout_ids, value, layout);
+                    decrement_refcount_layout(env, layout_ids, value, layout);
                 }
             }
 
diff --git a/crates/compiler/gen_llvm/src/llvm/build.rs b/crates/compiler/gen_llvm/src/llvm/build.rs
index 73126c90b1..9a6ffcfc3c 100644
--- a/crates/compiler/gen_llvm/src/llvm/build.rs
+++ b/crates/compiler/gen_llvm/src/llvm/build.rs
@@ -126,7 +126,7 @@ impl<'ctx> Iterator for FunctionIterator<'ctx> {
     }
 }
 
-#[derive(Default, Debug, Clone, PartialEq)]
+#[derive(Default, Debug, Clone, PartialEq, Eq)]
 pub struct Scope<'a, 'ctx> {
     symbols: ImMap<Symbol, (Layout<'a>, BasicValueEnum<'ctx>)>,
     pub top_level_thunks: ImMap<Symbol, (ProcLayout<'a>, FunctionValue<'ctx>)>,
@@ -973,7 +973,7 @@ pub fn build_exp_literal<'a, 'ctx, 'env>(
                     _ => unreachable!("incorrect small_str_bytes"),
                 }
             } else {
-                let ptr = define_global_str_literal_ptr(env, *str_literal);
+                let ptr = define_global_str_literal_ptr(env, str_literal);
                 let number_of_elements = env.ptr_int().const_int(str_literal.len() as u64, false);
 
                 let alloca =
@@ -2723,14 +2723,7 @@ pub fn build_exp_stmt<'a, 'ctx, 'env>(
                     let layout = *layout;
 
                     if layout.contains_refcounted(env.layout_interner) {
-                        increment_refcount_layout(
-                            env,
-                            parent,
-                            layout_ids,
-                            *inc_amount,
-                            value,
-                            &layout,
-                        );
+                        increment_refcount_layout(env, layout_ids, *inc_amount, value, &layout);
                     }
 
                     build_exp_stmt(env, layout_ids, func_spec_solutions, scope, parent, cont)
@@ -2739,7 +2732,7 @@ pub fn build_exp_stmt<'a, 'ctx, 'env>(
                     let (value, layout) = load_symbol_and_layout(scope, symbol);
 
                     if layout.contains_refcounted(env.layout_interner) {
-                        decrement_refcount_layout(env, parent, layout_ids, value, layout);
+                        decrement_refcount_layout(env, layout_ids, value, layout);
                     }
 
                     build_exp_stmt(env, layout_ids, func_spec_solutions, scope, parent, cont)
@@ -3847,12 +3840,9 @@ fn expose_function_to_host_help_c_abi_v2<'a, 'ctx, 'env>(
                             arg_type.into_pointer_type().get_element_type(),
                         );
                         // C return pointer goes at the beginning of params, and we must skip it if it exists.
-                        let param_index = (i
-                            + (if matches!(cc_return, CCReturn::ByPointer) {
-                                1
-                            } else {
-                                0
-                            })) as u32;
+                        let returns_pointer = matches!(cc_return, CCReturn::ByPointer);
+                        let param_index = i as u32 + returns_pointer as u32;
+
                         c_function.add_attribute(AttributeLoc::Param(param_index), byval);
                         c_function.add_attribute(AttributeLoc::Param(param_index), nonnull);
                     }
@@ -4554,7 +4544,7 @@ fn build_procedures_help<'a, 'ctx, 'env>(
                 fn_val.print_to_stderr();
 
                 if let Some(app_ll_file) = debug_output_file {
-                    env.module.print_to_file(&app_ll_file).unwrap();
+                    env.module.print_to_file(app_ll_file).unwrap();
 
                     panic!(
                         r"😱 LLVM errors when defining function {:?}; I wrote the full LLVM IR to {:?}",
@@ -6209,14 +6199,7 @@ fn run_low_level<'a, 'ctx, 'env>(
 
             let element_layout = list_element_layout!(list_layout);
 
-            list_get_unsafe(
-                env,
-                layout_ids,
-                parent,
-                element_layout,
-                elem_index,
-                wrapper_struct,
-            )
+            list_get_unsafe(env, layout_ids, element_layout, elem_index, wrapper_struct)
         }
         ListReplaceUnsafe => {
             let list = load_symbol(scope, &args[0]);
diff --git a/crates/compiler/gen_llvm/src/llvm/build_list.rs b/crates/compiler/gen_llvm/src/llvm/build_list.rs
index e2dccc7593..c8fd1f425a 100644
--- a/crates/compiler/gen_llvm/src/llvm/build_list.rs
+++ b/crates/compiler/gen_llvm/src/llvm/build_list.rs
@@ -121,7 +121,6 @@ pub(crate) fn list_with_capacity<'a, 'ctx, 'env>(
 pub(crate) fn list_get_unsafe<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
     layout_ids: &mut LayoutIds<'a>,
-    parent: FunctionValue<'ctx>,
     element_layout: &Layout<'a>,
     elem_index: IntValue<'ctx>,
     wrapper_struct: StructValue<'ctx>,
@@ -140,7 +139,7 @@ pub(crate) fn list_get_unsafe<'a, 'ctx, 'env>(
 
     let result = load_roc_value(env, *element_layout, elem_ptr, "list_get_load_element");
 
-    increment_refcount_layout(env, parent, layout_ids, 1, result, element_layout);
+    increment_refcount_layout(env, layout_ids, 1, result, element_layout);
 
     result
 }
diff --git a/crates/compiler/gen_llvm/src/llvm/refcounting.rs b/crates/compiler/gen_llvm/src/llvm/refcounting.rs
index 25cbea9e1c..467110004b 100644
--- a/crates/compiler/gen_llvm/src/llvm/refcounting.rs
+++ b/crates/compiler/gen_llvm/src/llvm/refcounting.rs
@@ -327,8 +327,6 @@ fn modify_refcount_struct_help<'a, 'ctx, 'env>(
 
     arg_val.set_name(arg_symbol.as_str(&env.interns));
 
-    let parent = fn_val;
-
     let wrapper_struct = arg_val.into_struct_value();
 
     for (i, field_layout) in layouts.iter().enumerate() {
@@ -347,7 +345,6 @@ fn modify_refcount_struct_help<'a, 'ctx, 'env>(
 
             modify_refcount_layout_help(
                 env,
-                parent,
                 layout_ids,
                 mode.to_call_mode(fn_val),
                 when_recursive,
@@ -362,42 +359,32 @@ fn modify_refcount_struct_help<'a, 'ctx, 'env>(
 
 pub fn increment_refcount_layout<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    parent: FunctionValue<'ctx>,
     layout_ids: &mut LayoutIds<'a>,
     inc_amount: u64,
     value: BasicValueEnum<'ctx>,
     layout: &Layout<'a>,
 ) {
     let amount = env.ptr_int().const_int(inc_amount, false);
-    increment_n_refcount_layout(env, parent, layout_ids, amount, value, layout);
+    increment_n_refcount_layout(env, layout_ids, amount, value, layout);
 }
 
 pub fn increment_n_refcount_layout<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    parent: FunctionValue<'ctx>,
     layout_ids: &mut LayoutIds<'a>,
     amount: IntValue<'ctx>,
     value: BasicValueEnum<'ctx>,
     layout: &Layout<'a>,
 ) {
-    modify_refcount_layout(
-        env,
-        parent,
-        layout_ids,
-        CallMode::Inc(amount),
-        value,
-        layout,
-    );
+    modify_refcount_layout(env, layout_ids, CallMode::Inc(amount), value, layout);
 }
 
 pub fn decrement_refcount_layout<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    parent: FunctionValue<'ctx>,
     layout_ids: &mut LayoutIds<'a>,
     value: BasicValueEnum<'ctx>,
     layout: &Layout<'a>,
 ) {
-    modify_refcount_layout(env, parent, layout_ids, CallMode::Dec, value, layout);
+    modify_refcount_layout(env, layout_ids, CallMode::Dec, value, layout);
 }
 
 fn modify_refcount_builtin<'a, 'ctx, 'env>(
@@ -435,7 +422,6 @@ fn modify_refcount_builtin<'a, 'ctx, 'env>(
 
 fn modify_refcount_layout<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    parent: FunctionValue<'ctx>,
     layout_ids: &mut LayoutIds<'a>,
     call_mode: CallMode<'ctx>,
     value: BasicValueEnum<'ctx>,
@@ -443,7 +429,6 @@ fn modify_refcount_layout<'a, 'ctx, 'env>(
 ) {
     modify_refcount_layout_help(
         env,
-        parent,
         layout_ids,
         call_mode,
         &WhenRecursive::Unreachable,
@@ -460,7 +445,6 @@ enum WhenRecursive<'a> {
 
 fn modify_refcount_layout_help<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    parent: FunctionValue<'ctx>,
     layout_ids: &mut LayoutIds<'a>,
     call_mode: CallMode<'ctx>,
     when_recursive: &WhenRecursive<'a>,
@@ -474,7 +458,6 @@ fn modify_refcount_layout_help<'a, 'ctx, 'env>(
 
     let function = match modify_refcount_layout_build_function(
         env,
-        parent,
         layout_ids,
         mode,
         when_recursive,
@@ -538,7 +521,6 @@ fn call_help<'a, 'ctx, 'env>(
 
 fn modify_refcount_layout_build_function<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
-    parent: FunctionValue<'ctx>,
     layout_ids: &mut LayoutIds<'a>,
     mode: Mode,
     when_recursive: &WhenRecursive<'a>,
@@ -603,7 +585,6 @@ fn modify_refcount_layout_build_function<'a, 'ctx, 'env>(
 
                 let function = modify_refcount_layout_build_function(
                     env,
-                    parent,
                     layout_ids,
                     mode,
                     when_recursive,
@@ -615,7 +596,6 @@ fn modify_refcount_layout_build_function<'a, 'ctx, 'env>(
         },
         LambdaSet(lambda_set) => modify_refcount_layout_build_function(
             env,
-            parent,
             layout_ids,
             mode,
             when_recursive,
@@ -731,7 +711,6 @@ fn modify_refcount_list_help<'a, 'ctx, 'env>(
         let loop_fn = |_index, element| {
             modify_refcount_layout_help(
                 env,
-                parent,
                 layout_ids,
                 mode.to_call_mode(fn_val),
                 when_recursive,
@@ -1302,7 +1281,6 @@ fn build_rec_union_recursive_decrement<'a, 'ctx, 'env>(
         for (field, field_layout) in deferred_nonrec {
             modify_refcount_layout_help(
                 env,
-                parent,
                 layout_ids,
                 mode.to_call_mode(decrement_fn),
                 when_recursive,
@@ -1366,7 +1344,7 @@ fn union_layout_tags<'a>(
     match union_layout {
         NullableWrapped {
             other_tags: tags, ..
-        } => *tags,
+        } => tags,
         NullableUnwrapped { other_fields, .. } => arena.alloc([*other_fields]),
         NonNullableUnwrapped(fields) => arena.alloc([*fields]),
         Recursive(tags) => tags,
@@ -1687,7 +1665,6 @@ fn modify_refcount_union_help<'a, 'ctx, 'env>(
 
                 modify_refcount_layout_help(
                     env,
-                    parent,
                     layout_ids,
                     mode.to_call_mode(fn_val),
                     when_recursive,
@@ -1709,7 +1686,6 @@ fn modify_refcount_union_help<'a, 'ctx, 'env>(
 
                 modify_refcount_layout_help(
                     env,
-                    parent,
                     layout_ids,
                     mode.to_call_mode(fn_val),
                     when_recursive,
diff --git a/crates/compiler/gen_wasm/src/backend.rs b/crates/compiler/gen_wasm/src/backend.rs
index 1b8b26f3d7..53f6a48981 100644
--- a/crates/compiler/gen_wasm/src/backend.rs
+++ b/crates/compiler/gen_wasm/src/backend.rs
@@ -1237,7 +1237,7 @@ impl<'a> WasmBackend<'a> {
             }
 
             CallType::HigherOrder(higher_order_lowlevel) => {
-                call_higher_order_lowlevel(self, ret_sym, ret_layout, *higher_order_lowlevel)
+                call_higher_order_lowlevel(self, ret_sym, ret_layout, higher_order_lowlevel)
             }
 
             CallType::Foreign {
diff --git a/crates/compiler/gen_wasm/src/wasm_module/code_builder.rs b/crates/compiler/gen_wasm/src/wasm_module/code_builder.rs
index 5adb833a60..d4b1ef3c36 100644
--- a/crates/compiler/gen_wasm/src/wasm_module/code_builder.rs
+++ b/crates/compiler/gen_wasm/src/wasm_module/code_builder.rs
@@ -69,7 +69,7 @@ impl std::fmt::Debug for VmBlock<'_> {
 /// Rust representation matches Wasm encoding.
 /// It's an error to specify alignment higher than the "natural" alignment of the instruction
 #[repr(u8)]
-#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd)]
 pub enum Align {
     Bytes1 = 0,
     Bytes2 = 1,
@@ -111,7 +111,7 @@ impl From<u32> for Align {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Copy)]
+#[derive(Debug, Clone, PartialEq, Eq, Copy)]
 pub enum VmSymbolState {
     /// Value doesn't exist yet
     NotYetPushed,
diff --git a/crates/compiler/gen_wasm/src/wasm_module/sections.rs b/crates/compiler/gen_wasm/src/wasm_module/sections.rs
index dfb69bc7dd..705fd1442d 100644
--- a/crates/compiler/gen_wasm/src/wasm_module/sections.rs
+++ b/crates/compiler/gen_wasm/src/wasm_module/sections.rs
@@ -303,7 +303,7 @@ impl<'a> Serialize for TypeSection<'a> {
  *
  *******************************************************************/
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum ImportDesc {
     Func { signature_index: u32 },
     Table { ty: TableType },
@@ -359,7 +359,7 @@ impl Serialize for ImportDesc {
     }
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
 pub struct Import<'a> {
     pub module: &'a str,
     pub name: &'a str,
@@ -551,7 +551,7 @@ impl Parse<()> for RefType {
         }
     }
 }
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
 pub struct TableType {
     pub ref_type: RefType,
     pub limits: Limits,
@@ -659,7 +659,7 @@ impl Serialize for TableSection {
  *
  *******************************************************************/
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum Limits {
     Min(u32),
     MinMax(u32, u32),
@@ -749,7 +749,7 @@ section_impl!(MemorySection, SectionId::Memory);
  *
  *******************************************************************/
 
-#[derive(Debug, PartialEq, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub struct GlobalType {
     pub value_type: ValueType,
     pub is_mutable: bool,
diff --git a/crates/compiler/load/build.rs b/crates/compiler/load/build.rs
index 204f6af893..e13232efc8 100644
--- a/crates/compiler/load/build.rs
+++ b/crates/compiler/load/build.rs
@@ -44,7 +44,7 @@ fn write_subs_for_module(module_id: ModuleId, filename: &str) {
     println!("cargo:rerun-if-changed={}", filepath.to_str().unwrap());
 
     let mut output_path = PathBuf::from(std::env::var("OUT_DIR").unwrap());
-    output_path.extend(&[filename]);
+    output_path.extend([filename]);
     output_path.set_extension("dat");
 
     #[cfg(not(windows))]
@@ -64,7 +64,7 @@ fn write_subs_for_module(module_id: ModuleId, filename: &str) {
 
 fn write_types_for_module_dummy(output_path: &Path) {
     // write out a dummy file
-    std::fs::write(output_path, &[]).unwrap();
+    std::fs::write(output_path, []).unwrap();
 }
 
 #[cfg(not(windows))]
@@ -107,7 +107,7 @@ fn write_types_for_module_real(module_id: ModuleId, filename: &str, output_path:
     let abilities = module.abilities_store;
     let solved_implementations = module.resolved_implementations;
 
-    let mut file = std::fs::File::create(&output_path).unwrap();
+    let mut file = std::fs::File::create(output_path).unwrap();
 
     let type_state = TypeState {
         subs,
diff --git a/crates/compiler/load_internal/src/file.rs b/crates/compiler/load_internal/src/file.rs
index 31d280dca7..9bbf5c37d1 100644
--- a/crates/compiler/load_internal/src/file.rs
+++ b/crates/compiler/load_internal/src/file.rs
@@ -3100,7 +3100,7 @@ fn load_platform_module<'a>(
 ) -> Result<Msg<'a>, LoadingProblem<'a>> {
     let module_start_time = Instant::now();
     let file_io_start = Instant::now();
-    let file = fs::read(&filename);
+    let file = fs::read(filename);
     let file_io_duration = file_io_start.elapsed();
 
     match file {
diff --git a/crates/compiler/module/src/called_via.rs b/crates/compiler/module/src/called_via.rs
index bc314e0eec..17017a1917 100644
--- a/crates/compiler/module/src/called_via.rs
+++ b/crates/compiler/module/src/called_via.rs
@@ -70,7 +70,7 @@ pub enum ArgSide {
     Right,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum Associativity {
     /// left-associative operators:
     ///
diff --git a/crates/compiler/module/src/symbol.rs b/crates/compiler/module/src/symbol.rs
index f01026f0e3..e373557750 100644
--- a/crates/compiler/module/src/symbol.rs
+++ b/crates/compiler/module/src/symbol.rs
@@ -44,7 +44,7 @@ const SYMBOL_HAS_NICHE: () =
 // register_debug_idents calls (which should be made in debug mode).
 // Set it to false if you want to see the raw ModuleId and IdentId ints,
 // but please set it back to true before checking in the result!
-#[cfg(debug_assertions)]
+#[cfg(any(debug_assertions, feature = "debug-symbols"))]
 const PRETTY_PRINT_DEBUG_SYMBOLS: bool = true;
 
 pub const DERIVABLE_ABILITIES: &[(Symbol, &[Symbol])] = &[
@@ -183,7 +183,7 @@ impl Symbol {
 ///
 /// `Foo.bar`
 impl fmt::Debug for Symbol {
-    #[cfg(debug_assertions)]
+    #[cfg(any(debug_assertions, feature = "debug-symbols"))]
     #[allow(clippy::print_in_format_impl)]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         if PRETTY_PRINT_DEBUG_SYMBOLS {
@@ -216,7 +216,7 @@ impl fmt::Debug for Symbol {
         }
     }
 
-    #[cfg(not(debug_assertions))]
+    #[cfg(not(any(debug_assertions, feature = "debug-symbols")))]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fallback_debug_fmt(*self, f)
     }
@@ -256,7 +256,7 @@ fn fallback_debug_fmt(symbol: Symbol, f: &mut fmt::Formatter) -> fmt::Result {
 // end up using it in release builds anyway. Right? ...Right?
 lazy_static! {}
 
-#[cfg(debug_assertions)]
+#[cfg(any(debug_assertions, feature = "debug-symbols"))]
 lazy_static! {
     /// This is used in Debug builds only, to let us have a Debug instance
     /// which displays not only the Module ID, but also the Module Name which
@@ -399,7 +399,7 @@ impl fmt::Debug for ModuleId {
     /// needs a global mutex, so we don't do this in release builds. This means
     /// the Debug impl in release builds only shows the number, not the name (which
     /// it does not have available, due to having never stored it in the mutexed intern table.)
-    #[cfg(debug_assertions)]
+    #[cfg(any(debug_assertions, feature = "debug-symbols"))]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         // Originally, this printed both name and numeric ID, but the numeric ID
         // didn't seem to add anything useful. Feel free to temporarily re-add it
@@ -425,7 +425,7 @@ impl fmt::Debug for ModuleId {
     }
 
     /// In release builds, all we have access to is the number, so only display that.
-    #[cfg(not(debug_assertions))]
+    #[cfg(not(any(debug_assertions, feature = "debug-symbols")))]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.0.fmt(f)
     }
@@ -470,7 +470,7 @@ impl<'a> PackageModuleIds<'a> {
         // didn't find it, so we'll add it
         let module_id = ModuleId::from_zero_indexed(self.by_id.len());
         self.by_id.push(module_name.clone());
-        if cfg!(debug_assertions) {
+        if cfg!(any(debug_assertions, feature = "debug-symbols")) {
             Self::insert_debug_name(module_id, module_name);
         }
 
@@ -487,7 +487,7 @@ impl<'a> PackageModuleIds<'a> {
         ModuleIds { by_id }
     }
 
-    #[cfg(debug_assertions)]
+    #[cfg(any(debug_assertions, feature = "debug-symbols"))]
     fn insert_debug_name(module_id: ModuleId, module_name: &PQModuleName) {
         let mut names = DEBUG_MODULE_ID_NAMES.lock().expect("Failed to acquire lock for Debug interning into DEBUG_MODULE_ID_NAMES, presumably because a thread panicked.");
 
@@ -503,7 +503,7 @@ impl<'a> PackageModuleIds<'a> {
         }
     }
 
-    #[cfg(not(debug_assertions))]
+    #[cfg(not(any(debug_assertions, feature = "debug-symbols")))]
     fn insert_debug_name(_module_id: ModuleId, _module_name: &PQModuleName) {
         // By design, this is a no-op in release builds!
     }
@@ -557,14 +557,14 @@ impl ModuleIds {
         // didn't find it, so we'll add it
         let module_id = ModuleId::from_zero_indexed(self.by_id.len());
         self.by_id.push(module_name.clone());
-        if cfg!(debug_assertions) {
+        if cfg!(any(debug_assertions, feature = "debug-symbols")) {
             Self::insert_debug_name(module_id, module_name);
         }
 
         module_id
     }
 
-    #[cfg(debug_assertions)]
+    #[cfg(any(debug_assertions, feature = "debug-symbols"))]
     fn insert_debug_name(module_id: ModuleId, module_name: &ModuleName) {
         let mut names = DEBUG_MODULE_ID_NAMES.lock().expect("Failed to acquire lock for Debug interning into DEBUG_MODULE_ID_NAMES, presumably because a thread panicked.");
 
@@ -574,7 +574,7 @@ impl ModuleIds {
         }
     }
 
-    #[cfg(not(debug_assertions))]
+    #[cfg(not(any(debug_assertions, feature = "debug-symbols")))]
     fn insert_debug_name(_module_id: ModuleId, _module_name: &ModuleName) {
         // By design, this is a no-op in release builds!
     }
@@ -868,7 +868,7 @@ macro_rules! define_builtins {
                         IdentIds{ interner }
                     };
 
-                    if cfg!(debug_assertions) {
+                    if cfg!(any(debug_assertions, feature = "debug-symbols")) {
                         let name = PQModuleName::Unqualified($module_name.into());
                         PackageModuleIds::insert_debug_name(module_id, &name);
                         module_id.register_debug_idents(&ident_ids);
@@ -910,7 +910,7 @@ macro_rules! define_builtins {
                 let mut insert_both = |id: ModuleId, name_str: &'static str| {
                     let name: ModuleName = name_str.into();
 
-                    if cfg!(debug_assertions) {
+                    if cfg!(any(debug_assertions, feature = "debug-symbols")) {
                         Self::insert_debug_name(id, &name);
                     }
 
@@ -936,7 +936,7 @@ macro_rules! define_builtins {
                     let raw_name: IdentStr = name_str.into();
                     let name = PQModuleName::Unqualified(raw_name.into());
 
-                    if cfg!(debug_assertions) {
+                    if cfg!(any(debug_assertions, feature = "debug-symbols")) {
                         Self::insert_debug_name(id, &name);
                     }
 
diff --git a/crates/compiler/mono/src/code_gen_help/mod.rs b/crates/compiler/mono/src/code_gen_help/mod.rs
index a9532aed88..07a27df060 100644
--- a/crates/compiler/mono/src/code_gen_help/mod.rs
+++ b/crates/compiler/mono/src/code_gen_help/mod.rs
@@ -471,7 +471,7 @@ impl<'a> CodeGenHelp<'a> {
     ) -> (bool, Vec<'a, Option<usize>>) {
         use UnionLayout::*;
         match union {
-            NonRecursive(_) => return (false, bumpalo::vec![in self.arena]),
+            NonRecursive(_) => (false, bumpalo::vec![in self.arena]),
 
             Recursive(tags) => self.union_tail_recursion_fields_help(tags),
 
diff --git a/crates/compiler/mono/src/ir.rs b/crates/compiler/mono/src/ir.rs
index 0dfdf0cdf8..98face2034 100644
--- a/crates/compiler/mono/src/ir.rs
+++ b/crates/compiler/mono/src/ir.rs
@@ -284,7 +284,7 @@ impl AbilityAliases {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CapturedSymbols<'a> {
     None,
     Captured(&'a [(Symbol, Variable)]),
@@ -317,7 +317,7 @@ pub struct Proc<'a> {
     pub host_exposed_layouts: HostExposedLayouts<'a>,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum HostExposedLayouts<'a> {
     NotHostExposed,
     HostExposed {
@@ -326,13 +326,13 @@ pub enum HostExposedLayouts<'a> {
     },
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum SelfRecursive {
     NotSelfRecursive,
     SelfRecursive(JoinPointId),
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Parens {
     NotNeeded,
     InTypeParam,
@@ -1575,7 +1575,7 @@ impl<'a, 'i> Env<'a, 'i> {
 #[derive(Clone, Debug, PartialEq, Copy, Eq, Hash)]
 pub struct JoinPointId(pub Symbol);
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct Param<'a> {
     pub symbol: Symbol,
     pub borrow: bool,
@@ -1659,7 +1659,7 @@ pub enum Stmt<'a> {
 }
 
 /// in the block below, symbol `scrutinee` is assumed be be of shape `tag_id`
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum BranchInfo<'a> {
     None,
     Constructor {
@@ -1702,7 +1702,7 @@ impl<'a> BranchInfo<'a> {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum ModifyRc {
     /// Increment a reference count
     Inc(Symbol, u64),
@@ -1848,7 +1848,7 @@ impl<'a> Call<'a> {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct CallSpecId {
     id: u32,
 }
@@ -1863,7 +1863,7 @@ impl CallSpecId {
     pub const BACKEND_DUMMY: Self = Self { id: 0 };
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct UpdateModeId {
     id: u32,
 }
@@ -1878,7 +1878,7 @@ impl UpdateModeId {
     pub const BACKEND_DUMMY: Self = Self { id: 0 };
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct UpdateModeIds {
     next: u32,
 }
@@ -1895,7 +1895,7 @@ impl UpdateModeIds {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum CallType<'a> {
     ByName {
         name: LambdaName<'a>,
@@ -1914,7 +1914,7 @@ pub enum CallType<'a> {
     HigherOrder(&'a HigherOrderLowLevel<'a>),
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct PassedFunction<'a> {
     /// name of the top-level function that is passed as an argument
     /// e.g. in `List.map xs Num.abs` this would be `Num.abs`
@@ -1931,7 +1931,7 @@ pub struct PassedFunction<'a> {
     pub owns_captured_environment: bool,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct HigherOrderLowLevel<'a> {
     pub op: crate::low_level::HigherOrder,
 
@@ -7009,7 +7009,7 @@ fn substitute_in_call<'a>(
         } => substitute(subs, name.name()).map(|new| CallType::ByName {
             name: name.replace_name(new),
             arg_layouts,
-            ret_layout: *ret_layout,
+            ret_layout,
             specialization_id: *specialization_id,
         }),
         CallType::Foreign { .. } => None,
@@ -7158,7 +7158,7 @@ fn substitute_in_expr<'a>(
         } => match substitute(subs, *structure) {
             Some(structure) => Some(StructAtIndex {
                 index: *index,
-                field_layouts: *field_layouts,
+                field_layouts,
                 structure,
             }),
             None => None,
diff --git a/crates/compiler/mono/src/low_level.rs b/crates/compiler/mono/src/low_level.rs
index 3856e95ba9..ddad554c81 100644
--- a/crates/compiler/mono/src/low_level.rs
+++ b/crates/compiler/mono/src/low_level.rs
@@ -1,6 +1,6 @@
 use roc_module::symbol::Symbol;
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum HigherOrder {
     ListMap {
         xs: Symbol,
diff --git a/crates/compiler/mono/src/reset_reuse.rs b/crates/compiler/mono/src/reset_reuse.rs
index feec4fe8e4..6b2447c250 100644
--- a/crates/compiler/mono/src/reset_reuse.rs
+++ b/crates/compiler/mono/src/reset_reuse.rs
@@ -128,7 +128,7 @@ fn function_s<'a, 'i>(
             remainder,
         } => {
             let id = *id;
-            let body: &Stmt = *body;
+            let body: &Stmt = body;
             let new_body = function_s(env, w, c, body);
 
             let new_join = if std::ptr::eq(body, new_body) || body == new_body {
@@ -179,7 +179,7 @@ fn function_s<'a, 'i>(
             arena.alloc(new_switch)
         }
         Refcounting(op, continuation) => {
-            let continuation: &Stmt = *continuation;
+            let continuation: &Stmt = continuation;
             let new_continuation = function_s(env, w, c, continuation);
 
             if std::ptr::eq(continuation, new_continuation) || continuation == new_continuation {
@@ -198,7 +198,7 @@ fn function_s<'a, 'i>(
             layouts,
             remainder,
         } => {
-            let continuation: &Stmt = *remainder;
+            let continuation: &Stmt = remainder;
             let new_continuation = function_s(env, w, c, continuation);
 
             if std::ptr::eq(continuation, new_continuation) || continuation == new_continuation {
@@ -223,7 +223,7 @@ fn function_s<'a, 'i>(
             layouts,
             remainder,
         } => {
-            let continuation: &Stmt = *remainder;
+            let continuation: &Stmt = remainder;
             let new_continuation = function_s(env, w, c, continuation);
 
             if std::ptr::eq(continuation, new_continuation) || continuation == new_continuation {
diff --git a/crates/compiler/parse/src/ast.rs b/crates/compiler/parse/src/ast.rs
index 16ce506c3d..1ec6995a8f 100644
--- a/crates/compiler/parse/src/ast.rs
+++ b/crates/compiler/parse/src/ast.rs
@@ -109,7 +109,7 @@ pub enum StrSegment<'a> {
     Interpolated(Loc<&'a Expr<'a>>), // e.g. (name) in "Hi, \(name)!"
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum EscapedChar {
     Newline,        // \n
     Tab,            // \t
@@ -581,7 +581,7 @@ pub enum AssignedField<'a, Val> {
     Malformed(&'a str),
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CommentOrNewline<'a> {
     Newline,
     LineComment(&'a str),
@@ -880,7 +880,7 @@ impl<'a, T> Collection<'a, T> {
 
     pub fn final_comments(&self) -> &'a [CommentOrNewline<'a>] {
         if let Some(final_comments) = self.final_comments {
-            *final_comments
+            final_comments
         } else {
             &[]
         }
diff --git a/crates/compiler/parse/src/expr.rs b/crates/compiler/parse/src/expr.rs
index 757af05a69..8f181c2833 100644
--- a/crates/compiler/parse/src/expr.rs
+++ b/crates/compiler/parse/src/expr.rs
@@ -346,6 +346,7 @@ fn parse_expr_start<'a>(
         loc!(move |a, s, m| parse_expr_operator_chain(m, options, a, s)),
         fail_expr_start_e()
     ]
+    .trace("expr_start")
     .parse(arena, state, min_indent)
 }
 
@@ -546,7 +547,7 @@ fn numeric_negate_expression<'a, T>(
     expr: Loc<Expr<'a>>,
     spaces: &'a [CommentOrNewline<'a>],
 ) -> Loc<Expr<'a>> {
-    debug_assert_eq!(state.bytes().get(0), Some(&b'-'));
+    debug_assert_eq!(state.bytes().first(), Some(&b'-'));
     // for overflow reasons, we must make the unary minus part of the number literal.
     let start = state.pos();
     let region = Region::new(start, expr.region.end());
@@ -941,7 +942,7 @@ fn parse_defs_end<'a>(
                                             ann_type: arena.alloc(*ann_type),
                                             comment,
                                             body_pattern: arena.alloc(loc_pattern),
-                                            body_expr: *arena.alloc(loc_def_expr),
+                                            body_expr: arena.alloc(loc_def_expr),
                                         };
 
                                         let region =
@@ -980,7 +981,7 @@ fn parse_defs_end<'a>(
                                             ann_type: arena.alloc(*ann_type),
                                             comment,
                                             body_pattern: arena.alloc(loc_pattern),
-                                            body_expr: *arena.alloc(loc_def_expr),
+                                            body_expr: arena.alloc(loc_def_expr),
                                         };
 
                                         let region =
@@ -1904,7 +1905,7 @@ fn expr_to_pattern_help<'a>(arena: &'a Bump, expr: &Expr<'a>) -> Result<Pattern<
         | Expr::UnaryOp(_, _) => Err(()),
 
         Expr::Str(string) => Ok(Pattern::StrLiteral(*string)),
-        Expr::SingleQuote(string) => Ok(Pattern::SingleQuote(*string)),
+        Expr::SingleQuote(string) => Ok(Pattern::SingleQuote(string)),
         Expr::MalformedIdent(string, _problem) => Ok(Pattern::Malformed(string)),
     }
 }
@@ -2076,10 +2077,10 @@ mod when {
                     parser::keyword_e(keyword::IS, EWhen::Is)
                 )
             ),
-            move |arena, state, progress, (case_indent, loc_condition), min_indent| {
+            move |arena, state, _progress, (case_indent, loc_condition), min_indent| {
                 if case_indent < min_indent {
                     return Err((
-                        progress,
+                        MadeProgress,
                         // TODO maybe pass case_indent here?
                         EWhen::PatternAlignment(5, state.pos()),
                         state,
@@ -2089,15 +2090,18 @@ mod when {
                 // Everything in the branches must be indented at least as much as the case itself.
                 let min_indent = case_indent;
 
-                let (p1, branches, state) = branches(options).parse(arena, state, min_indent)?;
+                let (_p1, branches, state) = branches(options)
+                    .parse(arena, state, min_indent)
+                    .map_err(|(_p, e, s)| (MadeProgress, e, s))?;
 
                 Ok((
-                    progress.or(p1),
+                    MadeProgress,
                     Expr::When(arena.alloc(loc_condition), branches.into_bump_slice()),
                     state,
                 ))
             },
         )
+        .trace("when")
     }
 
     /// Parsing when with indentation.
diff --git a/crates/compiler/parse/src/header.rs b/crates/compiler/parse/src/header.rs
index 4fd3266e65..8c09f2daf1 100644
--- a/crates/compiler/parse/src/header.rs
+++ b/crates/compiler/parse/src/header.rs
@@ -52,7 +52,7 @@ pub enum VersionComparison {
     DisallowsEqual,
 }
 
-#[derive(Copy, Clone, PartialEq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct PackageName<'a>(&'a str);
 
 impl<'a> PackageName<'a> {
@@ -160,7 +160,7 @@ pub struct HostedHeader<'a> {
     pub after_with: &'a [CommentOrNewline<'a>],
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum To<'a> {
     ExistingPackage(&'a str),
     NewPackage(PackageName<'a>),
@@ -262,7 +262,7 @@ pub struct TypedIdent<'a> {
     pub ann: Loc<TypeAnnotation<'a>>,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct PackageEntry<'a> {
     pub shorthand: &'a str,
     pub spaces_after_shorthand: &'a [CommentOrNewline<'a>],
diff --git a/crates/compiler/parse/src/parser.rs b/crates/compiler/parse/src/parser.rs
index bd00602b9a..328d4b3b0a 100644
--- a/crates/compiler/parse/src/parser.rs
+++ b/crates/compiler/parse/src/parser.rs
@@ -737,6 +737,7 @@ pub trait Parser<'a, Output, Error> {
     ) -> ParseResult<'a, Output, Error>;
 
     #[cfg(not(feature = "parse_debug_trace"))]
+    #[inline(always)]
     fn trace(self, _message: &'static str) -> Self
     where
         Self: Sized,
@@ -789,7 +790,7 @@ impl<'a, O: std::fmt::Debug, E: std::fmt::Debug, P: Parser<'a, O, E>> Parser<'a,
 where
     E: 'a,
 {
-    fn parse(&self, arena: &'a Bump, state: State<'a>) -> ParseResult<'a, O, E> {
+    fn parse(&self, arena: &'a Bump, state: State<'a>, min_indent: u32) -> ParseResult<'a, O, E> {
         use std::cell::RefCell;
 
         thread_local! {
@@ -803,7 +804,7 @@ where
         let cur_indent = INDENT.with(|i| *i.borrow());
 
         println!(
-            "{:>5?}: {}{:<50}",
+            "{:<5?}: {}{:<50}",
             state.pos(),
             &indent_text[..cur_indent * 2],
             self.message
@@ -1379,11 +1380,12 @@ macro_rules! and {
 macro_rules! one_of {
     ($p1:expr, $p2:expr) => {
         move |arena: &'a bumpalo::Bump, state: $crate::state::State<'a>, min_indent: u32| {
+            let original_state = state.clone();
 
             match $p1.parse(arena, state, min_indent) {
                 valid @ Ok(_) => valid,
                 Err((MadeProgress, fail, state)) => Err((MadeProgress, fail, state)),
-                Err((NoProgress, _, state)) => $p2.parse(arena, state, min_indent),
+                Err((NoProgress, _, _)) => $p2.parse(arena, original_state, min_indent),
             }
         }
     };
diff --git a/crates/compiler/parse/src/string_literal.rs b/crates/compiler/parse/src/string_literal.rs
index a0a957c2c0..dedff7ebc6 100644
--- a/crates/compiler/parse/src/string_literal.rs
+++ b/crates/compiler/parse/src/string_literal.rs
@@ -122,10 +122,7 @@ pub fn parse_single_quote<'a>() -> impl Parser<'a, &'a str, EString<'a>> {
     }
 }
 
-fn consume_indent<'a>(
-    mut state: State<'a>,
-    mut indent: u32,
-) -> Result<State, (Progress, EString<'a>, State<'a>)> {
+fn consume_indent(mut state: State, mut indent: u32) -> Result<State, (Progress, EString, State)> {
     while indent > 0 {
         match state.bytes().first() {
             Some(b' ') => {
diff --git a/crates/compiler/parse/tests/snapshots/fail/pattern_binds_keyword.expr.result-ast b/crates/compiler/parse/tests/snapshots/fail/pattern_binds_keyword.expr.result-ast
new file mode 100644
index 0000000000..0843d5c707
--- /dev/null
+++ b/crates/compiler/parse/tests/snapshots/fail/pattern_binds_keyword.expr.result-ast
@@ -0,0 +1 @@
+Expr(When(Arrow(@24), @24), @0)
\ No newline at end of file
diff --git a/crates/compiler/parse/tests/snapshots/fail/pattern_binds_keyword.expr.roc b/crates/compiler/parse/tests/snapshots/fail/pattern_binds_keyword.expr.roc
new file mode 100644
index 0000000000..e44e443eb0
--- /dev/null
+++ b/crates/compiler/parse/tests/snapshots/fail/pattern_binds_keyword.expr.roc
@@ -0,0 +1,6 @@
+when Just 4 is
+    Just when ->
+        4
+
+    _ ->
+        2
\ No newline at end of file
diff --git a/crates/compiler/parse/tests/snapshots/fail/when_missing_arrow.expr.result-ast b/crates/compiler/parse/tests/snapshots/fail/when_missing_arrow.expr.result-ast
new file mode 100644
index 0000000000..bd2fce1211
--- /dev/null
+++ b/crates/compiler/parse/tests/snapshots/fail/when_missing_arrow.expr.result-ast
@@ -0,0 +1 @@
+Expr(When(Arrow(@26), @20), @0)
\ No newline at end of file
diff --git a/crates/compiler/parse/tests/snapshots/fail/when_missing_arrow.expr.roc b/crates/compiler/parse/tests/snapshots/fail/when_missing_arrow.expr.roc
new file mode 100644
index 0000000000..31fb667aa9
--- /dev/null
+++ b/crates/compiler/parse/tests/snapshots/fail/when_missing_arrow.expr.roc
@@ -0,0 +1,3 @@
+when 5 is
+    1 -> 2
+    _
\ No newline at end of file
diff --git a/crates/compiler/parse/tests/test_parse.rs b/crates/compiler/parse/tests/test_parse.rs
index 86c5123cc1..8b38116a26 100644
--- a/crates/compiler/parse/tests/test_parse.rs
+++ b/crates/compiler/parse/tests/test_parse.rs
@@ -124,6 +124,8 @@ mod test_parse {
         fail/lambda_missing_indent.expr,
         fail/type_argument_no_arrow.expr,
         fail/type_double_comma.expr,
+        fail/when_missing_arrow.expr,
+        fail/pattern_binds_keyword.expr,
         pass/ability_demand_signature_is_multiline.expr,
         pass/ability_multi_line.expr,
         pass/ability_single_line.expr,
diff --git a/crates/compiler/problem/src/can.rs b/crates/compiler/problem/src/can.rs
index 627b97a1ad..c97c78a075 100644
--- a/crates/compiler/problem/src/can.rs
+++ b/crates/compiler/problem/src/can.rs
@@ -7,19 +7,19 @@ use roc_parse::pattern::PatternType;
 use roc_region::all::{Loc, Region};
 use roc_types::types::AliasKind;
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct CycleEntry {
     pub symbol: Symbol,
     pub symbol_region: Region,
     pub expr_region: Region,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum BadPattern {
     Unsupported(PatternType),
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum ShadowKind {
     Variable,
     Alias(Symbol),
@@ -28,7 +28,7 @@ pub enum ShadowKind {
 }
 
 /// Problems that can occur in the course of canonicalization.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum Problem {
     UnusedDef(Symbol, Region),
     UnusedImport(Symbol, Region),
@@ -190,13 +190,13 @@ pub enum Problem {
     },
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum ExtensionTypeKind {
     Record,
     TagUnion,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum PrecedenceProblem {
     BothNonAssociative(Region, Loc<BinOp>, Loc<BinOp>),
 }
@@ -245,7 +245,7 @@ pub enum FloatErrorKind {
     IntSuffix,
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum RuntimeError {
     Shadowing {
         original_region: Region,
@@ -368,7 +368,7 @@ impl RuntimeError {
     }
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum MalformedPatternProblem {
     MalformedInt,
     MalformedFloat,
diff --git a/crates/compiler/region/src/all.rs b/crates/compiler/region/src/all.rs
index 3eed5060d5..457810cdf9 100644
--- a/crates/compiler/region/src/all.rs
+++ b/crates/compiler/region/src/all.rs
@@ -133,7 +133,8 @@ impl Position {
 
 impl Debug for Position {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "@{}", self.offset)
+        write!(f, "@")?;
+        self.offset.fmt(f)
     }
 }
 
diff --git a/crates/compiler/solve/src/ability.rs b/crates/compiler/solve/src/ability.rs
index 130dcf3447..fc85ba7b94 100644
--- a/crates/compiler/solve/src/ability.rs
+++ b/crates/compiler/solve/src/ability.rs
@@ -31,7 +31,7 @@ pub enum AbilityImplError {
 }
 
 /// Indexes a requested deriving of an ability for an opaque type.
-#[derive(Debug, PartialEq, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub struct RequestedDeriveKey {
     pub opaque: Symbol,
     pub ability: Symbol,
diff --git a/crates/compiler/solve_problem/src/lib.rs b/crates/compiler/solve_problem/src/lib.rs
index db2fe70177..3e618057cf 100644
--- a/crates/compiler/solve_problem/src/lib.rs
+++ b/crates/compiler/solve_problem/src/lib.rs
@@ -32,7 +32,7 @@ pub enum TypeError {
     },
 }
 
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum Unfulfilled {
     /// No claimed implementation of an ability for an opaque type.
     OpaqueDoesNotImplement { typ: Symbol, ability: Symbol },
@@ -52,7 +52,7 @@ pub enum Unfulfilled {
     },
 }
 
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum UnderivableReason {
     NotABuiltin,
     /// The surface type is not derivable
@@ -61,7 +61,7 @@ pub enum UnderivableReason {
     NestedNotDerivable(ErrorType, NotDerivableContext),
 }
 
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum NotDerivableContext {
     NoContext,
     Function,
@@ -71,12 +71,12 @@ pub enum NotDerivableContext {
     Eq(NotDerivableEq),
 }
 
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum NotDerivableDecode {
     OptionalRecordField(Lowercase),
 }
 
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum NotDerivableEq {
     FloatingPoint,
 }
diff --git a/crates/compiler/test_gen/src/helpers/llvm.rs b/crates/compiler/test_gen/src/helpers/llvm.rs
index 896c050d72..70856acc73 100644
--- a/crates/compiler/test_gen/src/helpers/llvm.rs
+++ b/crates/compiler/test_gen/src/helpers/llvm.rs
@@ -341,11 +341,11 @@ fn annotate_with_debug_info<'ctx>(
     let app_bc_file = "/tmp/roc-debugir.bc";
 
     // write the ll code to a file, so we can modify it
-    module.print_to_file(&app_ll_file).unwrap();
+    module.print_to_file(app_ll_file).unwrap();
 
     // run the debugir https://github.com/vaivaswatha/debugir tool
     match Command::new("debugir")
-        .args(&["-instnamer", app_ll_file])
+        .args(["-instnamer", app_ll_file])
         .output()
     {
         Ok(_) => {}
@@ -361,11 +361,11 @@ fn annotate_with_debug_info<'ctx>(
     }
 
     Command::new("llvm-as")
-        .args(&[app_dbg_ll_file, "-o", app_bc_file])
+        .args([app_dbg_ll_file, "-o", app_bc_file])
         .output()
         .unwrap();
 
-    inkwell::module::Module::parse_bitcode_from_path(&app_bc_file, context).unwrap()
+    inkwell::module::Module::parse_bitcode_from_path(app_bc_file, context).unwrap()
 }
 
 #[allow(dead_code)]
@@ -459,7 +459,7 @@ fn llvm_module_to_wasm_file(
 
     let output = zig()
         .current_dir(dir_path)
-        .args(&[
+        .args([
             "wasm-ld",
             concat!(env!("OUT_DIR"), "/wasm_test_platform.wasm"),
             test_a_path.to_str().unwrap(),
diff --git a/crates/compiler/test_mono/Cargo.toml b/crates/compiler/test_mono/Cargo.toml
index 8b8c8c4261..dbde1764de 100644
--- a/crates/compiler/test_mono/Cargo.toml
+++ b/crates/compiler/test_mono/Cargo.toml
@@ -12,7 +12,7 @@ path = "src/tests.rs"
 
 [dev-dependencies]
 roc_collections = { path = "../collections" }
-roc_module = { path = "../module" }
+roc_module = { path = "../module", features = ["debug-symbols"] }
 roc_builtins = { path = "../builtins" }
 roc_load = { path = "../load" }
 roc_can = { path = "../can" }
diff --git a/crates/compiler/test_mono/generated/call_function_in_empty_list.txt b/crates/compiler/test_mono/generated/call_function_in_empty_list.txt
index d6a64cf200..5e5af921e0 100644
--- a/crates/compiler/test_mono/generated/call_function_in_empty_list.txt
+++ b/crates/compiler/test_mono/generated/call_function_in_empty_list.txt
@@ -1,7 +1,7 @@
 procedure List.5 (#Attr.2, #Attr.3):
-    let List.380 : List {} = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.2 #Attr.3;
+    let List.409 : List {} = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.2 #Attr.3;
     decref #Attr.2;
-    ret List.380;
+    ret List.409;
 
 procedure Test.2 (Test.3):
     let Test.7 : {} = Struct {};
diff --git a/crates/compiler/test_mono/generated/call_function_in_empty_list_unbound.txt b/crates/compiler/test_mono/generated/call_function_in_empty_list_unbound.txt
index 2b758f2f1e..947e114ed7 100644
--- a/crates/compiler/test_mono/generated/call_function_in_empty_list_unbound.txt
+++ b/crates/compiler/test_mono/generated/call_function_in_empty_list_unbound.txt
@@ -1,7 +1,7 @@
 procedure List.5 (#Attr.2, #Attr.3):
-    let List.380 : List [] = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.2 #Attr.3;
+    let List.409 : List [] = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.2 #Attr.3;
     decref #Attr.2;
-    ret List.380;
+    ret List.409;
 
 procedure Test.2 (Test.3):
     let Test.7 : {} = Struct {};
diff --git a/crates/compiler/test_mono/generated/choose_i128_layout.txt b/crates/compiler/test_mono/generated/choose_i128_layout.txt
index a8df0f6aeb..811ac35b19 100644
--- a/crates/compiler/test_mono/generated/choose_i128_layout.txt
+++ b/crates/compiler/test_mono/generated/choose_i128_layout.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.258 : I128 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : I128 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Test.0 ():
     let Test.6 : I128 = 18446744073709551616i64;
diff --git a/crates/compiler/test_mono/generated/choose_u128_layout.txt b/crates/compiler/test_mono/generated/choose_u128_layout.txt
index cbed3ede38..acf76c6677 100644
--- a/crates/compiler/test_mono/generated/choose_u128_layout.txt
+++ b/crates/compiler/test_mono/generated/choose_u128_layout.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : U128 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : U128 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.2 : U128 = 170141183460469231731687303715884105728u128;
diff --git a/crates/compiler/test_mono/generated/choose_u64_layout.txt b/crates/compiler/test_mono/generated/choose_u64_layout.txt
index 8f967decc8..7a88a19504 100644
--- a/crates/compiler/test_mono/generated/choose_u64_layout.txt
+++ b/crates/compiler/test_mono/generated/choose_u64_layout.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.2 : U64 = 9999999999999999999i64;
diff --git a/crates/compiler/test_mono/generated/closure_in_list.txt b/crates/compiler/test_mono/generated/closure_in_list.txt
index 6741c034f9..a5d2cfc8c8 100644
--- a/crates/compiler/test_mono/generated/closure_in_list.txt
+++ b/crates/compiler/test_mono/generated/closure_in_list.txt
@@ -1,6 +1,6 @@
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure Test.1 (Test.5):
     let Test.2 : I64 = 41i64;
diff --git a/crates/compiler/test_mono/generated/dict.txt b/crates/compiler/test_mono/generated/dict.txt
index 8f4ea5f8b6..560247d7f4 100644
--- a/crates/compiler/test_mono/generated/dict.txt
+++ b/crates/compiler/test_mono/generated/dict.txt
@@ -1,14 +1,14 @@
 procedure Dict.1 ():
-    let Dict.100 : List {[], []} = Array [];
-    ret Dict.100;
+    let Dict.318 : List {[], []} = Array [];
+    ret Dict.318;
 
-procedure Dict.7 (Dict.94):
-    let Dict.99 : U64 = CallByName List.6 Dict.94;
-    ret Dict.99;
+procedure Dict.7 (Dict.312):
+    let Dict.317 : U64 = CallByName List.6 Dict.312;
+    ret Dict.317;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure Test.0 ():
     let Test.2 : List {[], []} = CallByName Dict.1;
diff --git a/crates/compiler/test_mono/generated/empty_list_of_function_type.txt b/crates/compiler/test_mono/generated/empty_list_of_function_type.txt
index 8b9698c414..50831ffd48 100644
--- a/crates/compiler/test_mono/generated/empty_list_of_function_type.txt
+++ b/crates/compiler/test_mono/generated/empty_list_of_function_type.txt
@@ -1,30 +1,30 @@
 procedure Bool.1 ():
-    let Bool.11 : Int1 = false;
-    ret Bool.11;
+    let Bool.23 : Int1 = false;
+    ret Bool.23;
 
-procedure List.2 (List.90, List.91):
-    let List.386 : U64 = CallByName List.6 List.90;
-    let List.382 : Int1 = CallByName Num.22 List.91 List.386;
-    if List.382 then
-        let List.384 : {} = CallByName List.66 List.90 List.91;
-        let List.383 : [C {}, C {}] = TagId(1) List.384;
-        ret List.383;
+procedure List.2 (List.94, List.95):
+    let List.415 : U64 = CallByName List.6 List.94;
+    let List.411 : Int1 = CallByName Num.22 List.95 List.415;
+    if List.411 then
+        let List.413 : {} = CallByName List.66 List.94 List.95;
+        let List.412 : [C {}, C {}] = TagId(1) List.413;
+        ret List.412;
     else
-        let List.381 : {} = Struct {};
-        let List.380 : [C {}, C {}] = TagId(0) List.381;
-        ret List.380;
+        let List.410 : {} = Struct {};
+        let List.409 : [C {}, C {}] = TagId(0) List.410;
+        ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.385 : {} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.385;
+    let List.414 : {} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.2 (Test.5):
     let Test.17 : Str = "bar";
diff --git a/crates/compiler/test_mono/generated/encode.txt b/crates/compiler/test_mono/generated/encode.txt
index 5a72793ccf..d2c1a0d87a 100644
--- a/crates/compiler/test_mono/generated/encode.txt
+++ b/crates/compiler/test_mono/generated/encode.txt
@@ -1,16 +1,16 @@
-procedure List.4 (List.101, List.102):
-    let List.383 : U64 = 1i64;
-    let List.381 : List U8 = CallByName List.70 List.101 List.383;
-    let List.380 : List U8 = CallByName List.71 List.381 List.102;
-    ret List.380;
+procedure List.4 (List.105, List.106):
+    let List.412 : U64 = 1i64;
+    let List.410 : List U8 = CallByName List.70 List.105 List.412;
+    let List.409 : List U8 = CallByName List.71 List.410 List.106;
+    ret List.409;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.384 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.384;
+    let List.413 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.382 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.382;
+    let List.411 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.411;
 
 procedure Test.23 (Test.24, Test.35, Test.22):
     let Test.37 : List U8 = CallByName List.4 Test.24 Test.22;
diff --git a/crates/compiler/test_mono/generated/encode_derived_nested_record_string.txt b/crates/compiler/test_mono/generated/encode_derived_nested_record_string.txt
index 6fa4d2ee16..069b904448 100644
--- a/crates/compiler/test_mono/generated/encode_derived_nested_record_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_nested_record_string.txt
@@ -44,7 +44,7 @@ procedure Encode.23 (Encode.94, Encode.102, Encode.96):
     ret Encode.106;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.113 : List U8 = CallByName Json.113 Encode.94 Encode.96 Encode.102;
+    let Encode.113 : List U8 = CallByName Json.112 Encode.94 Encode.96 Encode.102;
     ret Encode.113;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
@@ -52,11 +52,11 @@ procedure Encode.23 (Encode.94, Encode.102, Encode.96):
     ret Encode.115;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.125 : List U8 = CallByName Json.113 Encode.94 Encode.96 Encode.102;
+    let Encode.125 : List U8 = CallByName Json.112 Encode.94 Encode.96 Encode.102;
     ret Encode.125;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.128 : List U8 = CallByName Json.97 Encode.94 Encode.96 Encode.102;
+    let Encode.128 : List U8 = CallByName Json.96 Encode.94 Encode.96 Encode.102;
     ret Encode.128;
 
 procedure Encode.25 (Encode.100, Encode.101):
@@ -66,284 +66,284 @@ procedure Encode.25 (Encode.100, Encode.101):
     ret Encode.103;
 
 procedure Json.1 ():
-    let Json.396 : {} = Struct {};
-    ret Json.396;
+    let Json.394 : {} = Struct {};
+    ret Json.394;
 
-procedure Json.113 (Json.114, Json.399, Json.112):
-    let Json.432 : I32 = 123i64;
-    let Json.431 : U8 = CallByName Num.123 Json.432;
-    let Json.116 : List U8 = CallByName List.4 Json.114 Json.431;
-    let Json.430 : U64 = CallByName List.6 Json.112;
-    let Json.407 : {List U8, U64} = Struct {Json.116, Json.430};
-    let Json.408 : {} = Struct {};
-    let Json.406 : {List U8, U64} = CallByName List.18 Json.112 Json.407 Json.408;
-    dec Json.112;
-    let Json.118 : List U8 = StructAtIndex 0 Json.406;
-    inc Json.118;
-    dec Json.406;
-    let Json.405 : I32 = 125i64;
-    let Json.404 : U8 = CallByName Num.123 Json.405;
-    let Json.403 : List U8 = CallByName List.4 Json.118 Json.404;
-    ret Json.403;
+procedure Json.112 (Json.113, Json.397, Json.111):
+    let Json.430 : I64 = 123i64;
+    let Json.429 : U8 = CallByName Num.125 Json.430;
+    let Json.115 : List U8 = CallByName List.4 Json.113 Json.429;
+    let Json.428 : U64 = CallByName List.6 Json.111;
+    let Json.405 : {List U8, U64} = Struct {Json.115, Json.428};
+    let Json.406 : {} = Struct {};
+    let Json.404 : {List U8, U64} = CallByName List.18 Json.111 Json.405 Json.406;
+    dec Json.111;
+    let Json.117 : List U8 = StructAtIndex 0 Json.404;
+    inc Json.117;
+    dec Json.404;
+    let Json.403 : I64 = 125i64;
+    let Json.402 : U8 = CallByName Num.125 Json.403;
+    let Json.401 : List U8 = CallByName List.4 Json.117 Json.402;
+    ret Json.401;
 
-procedure Json.113 (Json.114, Json.399, Json.112):
-    let Json.472 : I32 = 123i64;
-    let Json.471 : U8 = CallByName Num.123 Json.472;
-    let Json.116 : List U8 = CallByName List.4 Json.114 Json.471;
-    let Json.470 : U64 = CallByName List.6 Json.112;
-    let Json.447 : {List U8, U64} = Struct {Json.116, Json.470};
-    let Json.448 : {} = Struct {};
-    let Json.446 : {List U8, U64} = CallByName List.18 Json.112 Json.447 Json.448;
-    dec Json.112;
-    let Json.118 : List U8 = StructAtIndex 0 Json.446;
-    inc Json.118;
-    dec Json.446;
-    let Json.445 : I32 = 125i64;
-    let Json.444 : U8 = CallByName Num.123 Json.445;
-    let Json.443 : List U8 = CallByName List.4 Json.118 Json.444;
-    ret Json.443;
+procedure Json.112 (Json.113, Json.397, Json.111):
+    let Json.470 : I64 = 123i64;
+    let Json.469 : U8 = CallByName Num.125 Json.470;
+    let Json.115 : List U8 = CallByName List.4 Json.113 Json.469;
+    let Json.468 : U64 = CallByName List.6 Json.111;
+    let Json.445 : {List U8, U64} = Struct {Json.115, Json.468};
+    let Json.446 : {} = Struct {};
+    let Json.444 : {List U8, U64} = CallByName List.18 Json.111 Json.445 Json.446;
+    dec Json.111;
+    let Json.117 : List U8 = StructAtIndex 0 Json.444;
+    inc Json.117;
+    dec Json.444;
+    let Json.443 : I64 = 125i64;
+    let Json.442 : U8 = CallByName Num.125 Json.443;
+    let Json.441 : List U8 = CallByName List.4 Json.117 Json.442;
+    ret Json.441;
 
-procedure Json.115 (Json.401, Json.402):
-    let Json.121 : Str = StructAtIndex 0 Json.402;
+procedure Json.114 (Json.399, Json.400):
+    let Json.120 : Str = StructAtIndex 0 Json.400;
+    inc Json.120;
+    let Json.121 : Str = StructAtIndex 1 Json.400;
     inc Json.121;
-    let Json.122 : Str = StructAtIndex 1 Json.402;
-    inc Json.122;
-    dec Json.402;
-    let Json.119 : List U8 = StructAtIndex 0 Json.401;
-    inc Json.119;
-    let Json.120 : U64 = StructAtIndex 1 Json.401;
-    dec Json.401;
-    let Json.429 : I32 = 34i64;
-    let Json.428 : U8 = CallByName Num.123 Json.429;
-    let Json.426 : List U8 = CallByName List.4 Json.119 Json.428;
-    let Json.427 : List U8 = CallByName Str.12 Json.121;
-    let Json.423 : List U8 = CallByName List.8 Json.426 Json.427;
-    let Json.425 : I32 = 34i64;
-    let Json.424 : U8 = CallByName Num.123 Json.425;
-    let Json.420 : List U8 = CallByName List.4 Json.423 Json.424;
-    let Json.422 : I32 = 58i64;
-    let Json.421 : U8 = CallByName Num.123 Json.422;
-    let Json.418 : List U8 = CallByName List.4 Json.420 Json.421;
-    let Json.419 : {} = Struct {};
-    let Json.123 : List U8 = CallByName Encode.23 Json.418 Json.122 Json.419;
-    joinpoint Json.413 Json.124:
-        let Json.411 : U64 = 1i64;
-        let Json.410 : U64 = CallByName Num.20 Json.120 Json.411;
-        let Json.409 : {List U8, U64} = Struct {Json.124, Json.410};
-        ret Json.409;
+    dec Json.400;
+    let Json.118 : List U8 = StructAtIndex 0 Json.399;
+    inc Json.118;
+    let Json.119 : U64 = StructAtIndex 1 Json.399;
+    dec Json.399;
+    let Json.427 : I64 = 34i64;
+    let Json.426 : U8 = CallByName Num.125 Json.427;
+    let Json.424 : List U8 = CallByName List.4 Json.118 Json.426;
+    let Json.425 : List U8 = CallByName Str.12 Json.120;
+    let Json.421 : List U8 = CallByName List.8 Json.424 Json.425;
+    let Json.423 : I64 = 34i64;
+    let Json.422 : U8 = CallByName Num.125 Json.423;
+    let Json.418 : List U8 = CallByName List.4 Json.421 Json.422;
+    let Json.420 : I64 = 58i64;
+    let Json.419 : U8 = CallByName Num.125 Json.420;
+    let Json.416 : List U8 = CallByName List.4 Json.418 Json.419;
+    let Json.417 : {} = Struct {};
+    let Json.122 : List U8 = CallByName Encode.23 Json.416 Json.121 Json.417;
+    joinpoint Json.411 Json.123:
+        let Json.409 : U64 = 1i64;
+        let Json.408 : U64 = CallByName Num.20 Json.119 Json.409;
+        let Json.407 : {List U8, U64} = Struct {Json.123, Json.408};
+        ret Json.407;
     in
-    let Json.417 : U64 = 1i64;
-    let Json.414 : Int1 = CallByName Num.24 Json.120 Json.417;
-    if Json.414 then
-        let Json.416 : I32 = 44i64;
-        let Json.415 : U8 = CallByName Num.123 Json.416;
-        let Json.412 : List U8 = CallByName List.4 Json.123 Json.415;
-        jump Json.413 Json.412;
+    let Json.415 : U64 = 1i64;
+    let Json.412 : Int1 = CallByName Num.24 Json.119 Json.415;
+    if Json.412 then
+        let Json.414 : I64 = 44i64;
+        let Json.413 : U8 = CallByName Num.125 Json.414;
+        let Json.410 : List U8 = CallByName List.4 Json.122 Json.413;
+        jump Json.411 Json.410;
     else
-        jump Json.413 Json.123;
+        jump Json.411 Json.122;
 
-procedure Json.115 (Json.401, Json.402):
-    let Json.121 : Str = StructAtIndex 0 Json.402;
+procedure Json.114 (Json.399, Json.400):
+    let Json.120 : Str = StructAtIndex 0 Json.400;
+    inc Json.120;
+    let Json.121 : Str = StructAtIndex 1 Json.400;
     inc Json.121;
-    let Json.122 : Str = StructAtIndex 1 Json.402;
-    inc Json.122;
-    dec Json.402;
-    let Json.119 : List U8 = StructAtIndex 0 Json.401;
-    inc Json.119;
-    let Json.120 : U64 = StructAtIndex 1 Json.401;
-    dec Json.401;
-    let Json.469 : I32 = 34i64;
-    let Json.468 : U8 = CallByName Num.123 Json.469;
-    let Json.466 : List U8 = CallByName List.4 Json.119 Json.468;
-    let Json.467 : List U8 = CallByName Str.12 Json.121;
-    let Json.463 : List U8 = CallByName List.8 Json.466 Json.467;
-    let Json.465 : I32 = 34i64;
-    let Json.464 : U8 = CallByName Num.123 Json.465;
-    let Json.460 : List U8 = CallByName List.4 Json.463 Json.464;
-    let Json.462 : I32 = 58i64;
-    let Json.461 : U8 = CallByName Num.123 Json.462;
-    let Json.458 : List U8 = CallByName List.4 Json.460 Json.461;
-    let Json.459 : {} = Struct {};
-    let Json.123 : List U8 = CallByName Encode.23 Json.458 Json.122 Json.459;
-    joinpoint Json.453 Json.124:
-        let Json.451 : U64 = 1i64;
-        let Json.450 : U64 = CallByName Num.20 Json.120 Json.451;
-        let Json.449 : {List U8, U64} = Struct {Json.124, Json.450};
-        ret Json.449;
+    dec Json.400;
+    let Json.118 : List U8 = StructAtIndex 0 Json.399;
+    inc Json.118;
+    let Json.119 : U64 = StructAtIndex 1 Json.399;
+    dec Json.399;
+    let Json.467 : I64 = 34i64;
+    let Json.466 : U8 = CallByName Num.125 Json.467;
+    let Json.464 : List U8 = CallByName List.4 Json.118 Json.466;
+    let Json.465 : List U8 = CallByName Str.12 Json.120;
+    let Json.461 : List U8 = CallByName List.8 Json.464 Json.465;
+    let Json.463 : I64 = 34i64;
+    let Json.462 : U8 = CallByName Num.125 Json.463;
+    let Json.458 : List U8 = CallByName List.4 Json.461 Json.462;
+    let Json.460 : I64 = 58i64;
+    let Json.459 : U8 = CallByName Num.125 Json.460;
+    let Json.456 : List U8 = CallByName List.4 Json.458 Json.459;
+    let Json.457 : {} = Struct {};
+    let Json.122 : List U8 = CallByName Encode.23 Json.456 Json.121 Json.457;
+    joinpoint Json.451 Json.123:
+        let Json.449 : U64 = 1i64;
+        let Json.448 : U64 = CallByName Num.20 Json.119 Json.449;
+        let Json.447 : {List U8, U64} = Struct {Json.123, Json.448};
+        ret Json.447;
     in
-    let Json.457 : U64 = 1i64;
-    let Json.454 : Int1 = CallByName Num.24 Json.120 Json.457;
-    if Json.454 then
-        let Json.456 : I32 = 44i64;
-        let Json.455 : U8 = CallByName Num.123 Json.456;
-        let Json.452 : List U8 = CallByName List.4 Json.123 Json.455;
-        jump Json.453 Json.452;
+    let Json.455 : U64 = 1i64;
+    let Json.452 : Int1 = CallByName Num.24 Json.119 Json.455;
+    if Json.452 then
+        let Json.454 : I64 = 44i64;
+        let Json.453 : U8 = CallByName Num.125 Json.454;
+        let Json.450 : List U8 = CallByName List.4 Json.122 Json.453;
+        jump Json.451 Json.450;
     else
-        jump Json.453 Json.123;
+        jump Json.451 Json.122;
 
-procedure Json.18 (Json.96):
-    let Json.473 : Str = CallByName Encode.22 Json.96;
-    ret Json.473;
+procedure Json.18 (Json.95):
+    let Json.471 : Str = CallByName Encode.22 Json.95;
+    ret Json.471;
 
-procedure Json.20 (Json.112):
-    let Json.397 : List {Str, Str} = CallByName Encode.22 Json.112;
-    ret Json.397;
+procedure Json.20 (Json.111):
+    let Json.395 : List {Str, Str} = CallByName Encode.22 Json.111;
+    ret Json.395;
 
-procedure Json.20 (Json.112):
-    let Json.439 : List {Str, Str} = CallByName Encode.22 Json.112;
-    ret Json.439;
+procedure Json.20 (Json.111):
+    let Json.437 : List {Str, Str} = CallByName Encode.22 Json.111;
+    ret Json.437;
 
-procedure Json.97 (Json.98, Json.475, Json.96):
-    let Json.484 : I32 = 34i64;
-    let Json.483 : U8 = CallByName Num.123 Json.484;
-    let Json.481 : List U8 = CallByName List.4 Json.98 Json.483;
-    let Json.482 : List U8 = CallByName Str.12 Json.96;
-    let Json.478 : List U8 = CallByName List.8 Json.481 Json.482;
-    let Json.480 : I32 = 34i64;
-    let Json.479 : U8 = CallByName Num.123 Json.480;
-    let Json.477 : List U8 = CallByName List.4 Json.478 Json.479;
-    ret Json.477;
+procedure Json.96 (Json.97, Json.473, Json.95):
+    let Json.482 : I64 = 34i64;
+    let Json.481 : U8 = CallByName Num.125 Json.482;
+    let Json.479 : List U8 = CallByName List.4 Json.97 Json.481;
+    let Json.480 : List U8 = CallByName Str.12 Json.95;
+    let Json.476 : List U8 = CallByName List.8 Json.479 Json.480;
+    let Json.478 : I64 = 34i64;
+    let Json.477 : U8 = CallByName Num.125 Json.478;
+    let Json.475 : List U8 = CallByName List.4 Json.476 Json.477;
+    ret Json.475;
 
-procedure List.133 (List.134, List.135, List.132):
-    let List.420 : {List U8, U64} = CallByName Json.115 List.134 List.135;
-    ret List.420;
+procedure List.137 (List.138, List.139, List.136):
+    let List.449 : {List U8, U64} = CallByName Json.114 List.138 List.139;
+    ret List.449;
 
-procedure List.133 (List.134, List.135, List.132):
-    let List.492 : {List U8, U64} = CallByName Json.115 List.134 List.135;
-    ret List.492;
+procedure List.137 (List.138, List.139, List.136):
+    let List.521 : {List U8, U64} = CallByName Json.114 List.138 List.139;
+    ret List.521;
 
-procedure List.18 (List.130, List.131, List.132):
-    let List.402 : {List U8, U64} = CallByName List.75 List.130 List.131 List.132;
-    ret List.402;
+procedure List.18 (List.134, List.135, List.136):
+    let List.431 : {List U8, U64} = CallByName List.89 List.134 List.135 List.136;
+    ret List.431;
 
-procedure List.18 (List.130, List.131, List.132):
-    let List.474 : {List U8, U64} = CallByName List.75 List.130 List.131 List.132;
-    ret List.474;
+procedure List.18 (List.134, List.135, List.136):
+    let List.503 : {List U8, U64} = CallByName List.89 List.134 List.135 List.136;
+    ret List.503;
 
-procedure List.4 (List.101, List.102):
-    let List.473 : U64 = 1i64;
-    let List.472 : List U8 = CallByName List.70 List.101 List.473;
-    let List.471 : List U8 = CallByName List.71 List.472 List.102;
-    ret List.471;
+procedure List.4 (List.105, List.106):
+    let List.502 : U64 = 1i64;
+    let List.501 : List U8 = CallByName List.70 List.105 List.502;
+    let List.500 : List U8 = CallByName List.71 List.501 List.106;
+    ret List.500;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.422 : U64 = lowlevel ListLen #Attr.2;
-    ret List.422;
+    let List.451 : U64 = lowlevel ListLen #Attr.2;
+    ret List.451;
 
 procedure List.6 (#Attr.2):
-    let List.495 : U64 = lowlevel ListLen #Attr.2;
-    ret List.495;
+    let List.524 : U64 = lowlevel ListLen #Attr.2;
+    ret List.524;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.417 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.417;
+    let List.446 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.446;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.489 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.489;
+    let List.518 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.518;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.452 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.452;
+    let List.481 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.481;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.450 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.450;
-
-procedure List.75 (List.356, List.357, List.358):
-    let List.406 : U64 = 0i64;
-    let List.407 : U64 = CallByName List.6 List.356;
-    let List.405 : {List U8, U64} = CallByName List.86 List.356 List.357 List.358 List.406 List.407;
-    ret List.405;
-
-procedure List.75 (List.356, List.357, List.358):
-    let List.478 : U64 = 0i64;
-    let List.479 : U64 = CallByName List.6 List.356;
-    let List.477 : {List U8, U64} = CallByName List.86 List.356 List.357 List.358 List.478 List.479;
-    ret List.477;
+    let List.479 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.479;
 
 procedure List.8 (#Attr.2, #Attr.3):
-    let List.494 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.494;
+    let List.523 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.523;
 
-procedure List.86 (List.432, List.433, List.434, List.435, List.436):
-    joinpoint List.408 List.359 List.360 List.361 List.362 List.363:
-        let List.410 : Int1 = CallByName Num.22 List.362 List.363;
-        if List.410 then
-            let List.416 : {Str, Str} = CallByName List.66 List.359 List.362;
-            let List.411 : {List U8, U64} = CallByName List.133 List.360 List.416 List.361;
-            let List.414 : U64 = 1i64;
-            let List.413 : U64 = CallByName Num.19 List.362 List.414;
-            jump List.408 List.359 List.411 List.361 List.413 List.363;
+procedure List.89 (List.385, List.386, List.387):
+    let List.435 : U64 = 0i64;
+    let List.436 : U64 = CallByName List.6 List.385;
+    let List.434 : {List U8, U64} = CallByName List.90 List.385 List.386 List.387 List.435 List.436;
+    ret List.434;
+
+procedure List.89 (List.385, List.386, List.387):
+    let List.507 : U64 = 0i64;
+    let List.508 : U64 = CallByName List.6 List.385;
+    let List.506 : {List U8, U64} = CallByName List.90 List.385 List.386 List.387 List.507 List.508;
+    ret List.506;
+
+procedure List.90 (List.461, List.462, List.463, List.464, List.465):
+    joinpoint List.437 List.388 List.389 List.390 List.391 List.392:
+        let List.439 : Int1 = CallByName Num.22 List.391 List.392;
+        if List.439 then
+            let List.445 : {Str, Str} = CallByName List.66 List.388 List.391;
+            let List.440 : {List U8, U64} = CallByName List.137 List.389 List.445 List.390;
+            let List.443 : U64 = 1i64;
+            let List.442 : U64 = CallByName Num.19 List.391 List.443;
+            jump List.437 List.388 List.440 List.390 List.442 List.392;
         else
-            ret List.360;
+            ret List.389;
     in
-    jump List.408 List.432 List.433 List.434 List.435 List.436;
+    jump List.437 List.461 List.462 List.463 List.464 List.465;
 
-procedure List.86 (List.505, List.506, List.507, List.508, List.509):
-    joinpoint List.480 List.359 List.360 List.361 List.362 List.363:
-        let List.482 : Int1 = CallByName Num.22 List.362 List.363;
-        if List.482 then
-            let List.488 : {Str, Str} = CallByName List.66 List.359 List.362;
-            let List.483 : {List U8, U64} = CallByName List.133 List.360 List.488 List.361;
-            let List.486 : U64 = 1i64;
-            let List.485 : U64 = CallByName Num.19 List.362 List.486;
-            jump List.480 List.359 List.483 List.361 List.485 List.363;
+procedure List.90 (List.534, List.535, List.536, List.537, List.538):
+    joinpoint List.509 List.388 List.389 List.390 List.391 List.392:
+        let List.511 : Int1 = CallByName Num.22 List.391 List.392;
+        if List.511 then
+            let List.517 : {Str, Str} = CallByName List.66 List.388 List.391;
+            let List.512 : {List U8, U64} = CallByName List.137 List.389 List.517 List.390;
+            let List.515 : U64 = 1i64;
+            let List.514 : U64 = CallByName Num.19 List.391 List.515;
+            jump List.509 List.388 List.512 List.390 List.514 List.392;
         else
-            ret List.360;
+            ret List.389;
     in
-    jump List.480 List.505 List.506 List.507 List.508 List.509;
+    jump List.509 List.534 List.535 List.536 List.537 List.538;
 
-procedure Num.123 (#Attr.2):
-    let Num.283 : U8 = lowlevel NumIntCast #Attr.2;
-    ret Num.283;
+procedure Num.125 (#Attr.2):
+    let Num.282 : U8 = lowlevel NumIntCast #Attr.2;
+    ret Num.282;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.286 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.286;
-
-procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.284 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.284;
-
-procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.287 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.287;
-
-procedure Num.24 (#Attr.2, #Attr.3):
-    let Num.285 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    let Num.285 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
     ret Num.285;
 
+procedure Num.20 (#Attr.2, #Attr.3):
+    let Num.283 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.283;
+
+procedure Num.22 (#Attr.2, #Attr.3):
+    let Num.286 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.286;
+
+procedure Num.24 (#Attr.2, #Attr.3):
+    let Num.284 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    ret Num.284;
+
 procedure Str.12 (#Attr.2):
-    let Str.268 : List U8 = lowlevel StrToUtf8 #Attr.2;
-    ret Str.268;
+    let Str.282 : List U8 = lowlevel StrToUtf8 #Attr.2;
+    ret Str.282;
 
 procedure Str.48 (#Attr.2, #Attr.3, #Attr.4):
-    let Str.260 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
-    ret Str.260;
+    let Str.274 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
+    ret Str.274;
 
-procedure Str.9 (Str.73):
-    let Str.258 : U64 = 0i64;
-    let Str.259 : U64 = CallByName List.6 Str.73;
-    let Str.74 : {U64, Str, Int1, U8} = CallByName Str.48 Str.73 Str.258 Str.259;
-    let Str.255 : Int1 = StructAtIndex 2 Str.74;
-    if Str.255 then
-        let Str.257 : Str = StructAtIndex 1 Str.74;
-        inc Str.257;
-        dec Str.74;
-        let Str.256 : [C {U64, U8}, C Str] = TagId(1) Str.257;
-        ret Str.256;
+procedure Str.9 (Str.76):
+    let Str.272 : U64 = 0i64;
+    let Str.273 : U64 = CallByName List.6 Str.76;
+    let Str.77 : {U64, Str, Int1, U8} = CallByName Str.48 Str.76 Str.272 Str.273;
+    let Str.269 : Int1 = StructAtIndex 2 Str.77;
+    if Str.269 then
+        let Str.271 : Str = StructAtIndex 1 Str.77;
+        inc Str.271;
+        dec Str.77;
+        let Str.270 : [C {U64, U8}, C Str] = TagId(1) Str.271;
+        ret Str.270;
     else
-        let Str.253 : U8 = StructAtIndex 3 Str.74;
-        let Str.254 : U64 = StructAtIndex 0 Str.74;
-        dec Str.74;
-        let Str.252 : {U64, U8} = Struct {Str.254, Str.253};
-        let Str.251 : [C {U64, U8}, C Str] = TagId(0) Str.252;
-        ret Str.251;
+        let Str.267 : U8 = StructAtIndex 3 Str.77;
+        let Str.268 : U64 = StructAtIndex 0 Str.77;
+        dec Str.77;
+        let Str.266 : {U64, U8} = Struct {Str.268, Str.267};
+        let Str.265 : [C {U64, U8}, C Str] = TagId(0) Str.266;
+        ret Str.265;
 
 procedure Test.0 ():
     let Test.12 : Str = "bar";
diff --git a/crates/compiler/test_mono/generated/encode_derived_record_one_field_string.txt b/crates/compiler/test_mono/generated/encode_derived_record_one_field_string.txt
index be6b0abf1b..9b81c3f70e 100644
--- a/crates/compiler/test_mono/generated/encode_derived_record_one_field_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_record_one_field_string.txt
@@ -25,11 +25,11 @@ procedure Encode.23 (Encode.94, Encode.102, Encode.96):
     ret Encode.106;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.113 : List U8 = CallByName Json.113 Encode.94 Encode.96 Encode.102;
+    let Encode.113 : List U8 = CallByName Json.112 Encode.94 Encode.96 Encode.102;
     ret Encode.113;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.116 : List U8 = CallByName Json.97 Encode.94 Encode.96 Encode.102;
+    let Encode.116 : List U8 = CallByName Json.96 Encode.94 Encode.96 Encode.102;
     ret Encode.116;
 
 procedure Encode.25 (Encode.100, Encode.101):
@@ -39,188 +39,188 @@ procedure Encode.25 (Encode.100, Encode.101):
     ret Encode.103;
 
 procedure Json.1 ():
-    let Json.396 : {} = Struct {};
-    ret Json.396;
+    let Json.394 : {} = Struct {};
+    ret Json.394;
 
-procedure Json.113 (Json.114, Json.399, Json.112):
-    let Json.432 : I32 = 123i64;
-    let Json.431 : U8 = CallByName Num.123 Json.432;
-    let Json.116 : List U8 = CallByName List.4 Json.114 Json.431;
-    let Json.430 : U64 = CallByName List.6 Json.112;
-    let Json.407 : {List U8, U64} = Struct {Json.116, Json.430};
-    let Json.408 : {} = Struct {};
-    let Json.406 : {List U8, U64} = CallByName List.18 Json.112 Json.407 Json.408;
-    dec Json.112;
-    let Json.118 : List U8 = StructAtIndex 0 Json.406;
-    inc Json.118;
-    dec Json.406;
-    let Json.405 : I32 = 125i64;
-    let Json.404 : U8 = CallByName Num.123 Json.405;
-    let Json.403 : List U8 = CallByName List.4 Json.118 Json.404;
-    ret Json.403;
+procedure Json.112 (Json.113, Json.397, Json.111):
+    let Json.430 : I64 = 123i64;
+    let Json.429 : U8 = CallByName Num.125 Json.430;
+    let Json.115 : List U8 = CallByName List.4 Json.113 Json.429;
+    let Json.428 : U64 = CallByName List.6 Json.111;
+    let Json.405 : {List U8, U64} = Struct {Json.115, Json.428};
+    let Json.406 : {} = Struct {};
+    let Json.404 : {List U8, U64} = CallByName List.18 Json.111 Json.405 Json.406;
+    dec Json.111;
+    let Json.117 : List U8 = StructAtIndex 0 Json.404;
+    inc Json.117;
+    dec Json.404;
+    let Json.403 : I64 = 125i64;
+    let Json.402 : U8 = CallByName Num.125 Json.403;
+    let Json.401 : List U8 = CallByName List.4 Json.117 Json.402;
+    ret Json.401;
 
-procedure Json.115 (Json.401, Json.402):
-    let Json.121 : Str = StructAtIndex 0 Json.402;
+procedure Json.114 (Json.399, Json.400):
+    let Json.120 : Str = StructAtIndex 0 Json.400;
+    inc Json.120;
+    let Json.121 : Str = StructAtIndex 1 Json.400;
     inc Json.121;
-    let Json.122 : Str = StructAtIndex 1 Json.402;
-    inc Json.122;
-    dec Json.402;
-    let Json.119 : List U8 = StructAtIndex 0 Json.401;
-    inc Json.119;
-    let Json.120 : U64 = StructAtIndex 1 Json.401;
-    dec Json.401;
-    let Json.429 : I32 = 34i64;
-    let Json.428 : U8 = CallByName Num.123 Json.429;
-    let Json.426 : List U8 = CallByName List.4 Json.119 Json.428;
-    let Json.427 : List U8 = CallByName Str.12 Json.121;
-    let Json.423 : List U8 = CallByName List.8 Json.426 Json.427;
-    let Json.425 : I32 = 34i64;
-    let Json.424 : U8 = CallByName Num.123 Json.425;
-    let Json.420 : List U8 = CallByName List.4 Json.423 Json.424;
-    let Json.422 : I32 = 58i64;
-    let Json.421 : U8 = CallByName Num.123 Json.422;
-    let Json.418 : List U8 = CallByName List.4 Json.420 Json.421;
-    let Json.419 : {} = Struct {};
-    let Json.123 : List U8 = CallByName Encode.23 Json.418 Json.122 Json.419;
-    joinpoint Json.413 Json.124:
-        let Json.411 : U64 = 1i64;
-        let Json.410 : U64 = CallByName Num.20 Json.120 Json.411;
-        let Json.409 : {List U8, U64} = Struct {Json.124, Json.410};
-        ret Json.409;
+    dec Json.400;
+    let Json.118 : List U8 = StructAtIndex 0 Json.399;
+    inc Json.118;
+    let Json.119 : U64 = StructAtIndex 1 Json.399;
+    dec Json.399;
+    let Json.427 : I64 = 34i64;
+    let Json.426 : U8 = CallByName Num.125 Json.427;
+    let Json.424 : List U8 = CallByName List.4 Json.118 Json.426;
+    let Json.425 : List U8 = CallByName Str.12 Json.120;
+    let Json.421 : List U8 = CallByName List.8 Json.424 Json.425;
+    let Json.423 : I64 = 34i64;
+    let Json.422 : U8 = CallByName Num.125 Json.423;
+    let Json.418 : List U8 = CallByName List.4 Json.421 Json.422;
+    let Json.420 : I64 = 58i64;
+    let Json.419 : U8 = CallByName Num.125 Json.420;
+    let Json.416 : List U8 = CallByName List.4 Json.418 Json.419;
+    let Json.417 : {} = Struct {};
+    let Json.122 : List U8 = CallByName Encode.23 Json.416 Json.121 Json.417;
+    joinpoint Json.411 Json.123:
+        let Json.409 : U64 = 1i64;
+        let Json.408 : U64 = CallByName Num.20 Json.119 Json.409;
+        let Json.407 : {List U8, U64} = Struct {Json.123, Json.408};
+        ret Json.407;
     in
-    let Json.417 : U64 = 1i64;
-    let Json.414 : Int1 = CallByName Num.24 Json.120 Json.417;
-    if Json.414 then
-        let Json.416 : I32 = 44i64;
-        let Json.415 : U8 = CallByName Num.123 Json.416;
-        let Json.412 : List U8 = CallByName List.4 Json.123 Json.415;
-        jump Json.413 Json.412;
+    let Json.415 : U64 = 1i64;
+    let Json.412 : Int1 = CallByName Num.24 Json.119 Json.415;
+    if Json.412 then
+        let Json.414 : I64 = 44i64;
+        let Json.413 : U8 = CallByName Num.125 Json.414;
+        let Json.410 : List U8 = CallByName List.4 Json.122 Json.413;
+        jump Json.411 Json.410;
     else
-        jump Json.413 Json.123;
+        jump Json.411 Json.122;
 
-procedure Json.18 (Json.96):
-    let Json.433 : Str = CallByName Encode.22 Json.96;
-    ret Json.433;
+procedure Json.18 (Json.95):
+    let Json.431 : Str = CallByName Encode.22 Json.95;
+    ret Json.431;
 
-procedure Json.20 (Json.112):
-    let Json.397 : List {Str, Str} = CallByName Encode.22 Json.112;
-    ret Json.397;
+procedure Json.20 (Json.111):
+    let Json.395 : List {Str, Str} = CallByName Encode.22 Json.111;
+    ret Json.395;
 
-procedure Json.97 (Json.98, Json.435, Json.96):
-    let Json.444 : I32 = 34i64;
-    let Json.443 : U8 = CallByName Num.123 Json.444;
-    let Json.441 : List U8 = CallByName List.4 Json.98 Json.443;
-    let Json.442 : List U8 = CallByName Str.12 Json.96;
-    let Json.438 : List U8 = CallByName List.8 Json.441 Json.442;
-    let Json.440 : I32 = 34i64;
-    let Json.439 : U8 = CallByName Num.123 Json.440;
-    let Json.437 : List U8 = CallByName List.4 Json.438 Json.439;
-    ret Json.437;
+procedure Json.96 (Json.97, Json.433, Json.95):
+    let Json.442 : I64 = 34i64;
+    let Json.441 : U8 = CallByName Num.125 Json.442;
+    let Json.439 : List U8 = CallByName List.4 Json.97 Json.441;
+    let Json.440 : List U8 = CallByName Str.12 Json.95;
+    let Json.436 : List U8 = CallByName List.8 Json.439 Json.440;
+    let Json.438 : I64 = 34i64;
+    let Json.437 : U8 = CallByName Num.125 Json.438;
+    let Json.435 : List U8 = CallByName List.4 Json.436 Json.437;
+    ret Json.435;
 
-procedure List.133 (List.134, List.135, List.132):
-    let List.426 : {List U8, U64} = CallByName Json.115 List.134 List.135;
-    ret List.426;
+procedure List.137 (List.138, List.139, List.136):
+    let List.455 : {List U8, U64} = CallByName Json.114 List.138 List.139;
+    ret List.455;
 
-procedure List.18 (List.130, List.131, List.132):
-    let List.408 : {List U8, U64} = CallByName List.75 List.130 List.131 List.132;
-    ret List.408;
+procedure List.18 (List.134, List.135, List.136):
+    let List.437 : {List U8, U64} = CallByName List.89 List.134 List.135 List.136;
+    ret List.437;
 
-procedure List.4 (List.101, List.102):
-    let List.407 : U64 = 1i64;
-    let List.406 : List U8 = CallByName List.70 List.101 List.407;
-    let List.405 : List U8 = CallByName List.71 List.406 List.102;
-    ret List.405;
+procedure List.4 (List.105, List.106):
+    let List.436 : U64 = 1i64;
+    let List.435 : List U8 = CallByName List.70 List.105 List.436;
+    let List.434 : List U8 = CallByName List.71 List.435 List.106;
+    ret List.434;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.429 : U64 = lowlevel ListLen #Attr.2;
-    ret List.429;
+    let List.458 : U64 = lowlevel ListLen #Attr.2;
+    ret List.458;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.423 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.423;
+    let List.452 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.452;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.386 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.386;
+    let List.415 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.415;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.384 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.384;
-
-procedure List.75 (List.356, List.357, List.358):
-    let List.412 : U64 = 0i64;
-    let List.413 : U64 = CallByName List.6 List.356;
-    let List.411 : {List U8, U64} = CallByName List.86 List.356 List.357 List.358 List.412 List.413;
-    ret List.411;
+    let List.413 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.8 (#Attr.2, #Attr.3):
-    let List.428 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.428;
+    let List.457 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.457;
 
-procedure List.86 (List.439, List.440, List.441, List.442, List.443):
-    joinpoint List.414 List.359 List.360 List.361 List.362 List.363:
-        let List.416 : Int1 = CallByName Num.22 List.362 List.363;
-        if List.416 then
-            let List.422 : {Str, Str} = CallByName List.66 List.359 List.362;
-            let List.417 : {List U8, U64} = CallByName List.133 List.360 List.422 List.361;
-            let List.420 : U64 = 1i64;
-            let List.419 : U64 = CallByName Num.19 List.362 List.420;
-            jump List.414 List.359 List.417 List.361 List.419 List.363;
+procedure List.89 (List.385, List.386, List.387):
+    let List.441 : U64 = 0i64;
+    let List.442 : U64 = CallByName List.6 List.385;
+    let List.440 : {List U8, U64} = CallByName List.90 List.385 List.386 List.387 List.441 List.442;
+    ret List.440;
+
+procedure List.90 (List.468, List.469, List.470, List.471, List.472):
+    joinpoint List.443 List.388 List.389 List.390 List.391 List.392:
+        let List.445 : Int1 = CallByName Num.22 List.391 List.392;
+        if List.445 then
+            let List.451 : {Str, Str} = CallByName List.66 List.388 List.391;
+            let List.446 : {List U8, U64} = CallByName List.137 List.389 List.451 List.390;
+            let List.449 : U64 = 1i64;
+            let List.448 : U64 = CallByName Num.19 List.391 List.449;
+            jump List.443 List.388 List.446 List.390 List.448 List.392;
         else
-            ret List.360;
+            ret List.389;
     in
-    jump List.414 List.439 List.440 List.441 List.442 List.443;
+    jump List.443 List.468 List.469 List.470 List.471 List.472;
 
-procedure Num.123 (#Attr.2):
-    let Num.264 : U8 = lowlevel NumIntCast #Attr.2;
-    ret Num.264;
+procedure Num.125 (#Attr.2):
+    let Num.263 : U8 = lowlevel NumIntCast #Attr.2;
+    ret Num.263;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.267 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.267;
-
-procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.265 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.265;
-
-procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.268 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.268;
-
-procedure Num.24 (#Attr.2, #Attr.3):
-    let Num.266 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    let Num.266 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
     ret Num.266;
 
+procedure Num.20 (#Attr.2, #Attr.3):
+    let Num.264 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.264;
+
+procedure Num.22 (#Attr.2, #Attr.3):
+    let Num.267 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.267;
+
+procedure Num.24 (#Attr.2, #Attr.3):
+    let Num.265 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    ret Num.265;
+
 procedure Str.12 (#Attr.2):
-    let Str.266 : List U8 = lowlevel StrToUtf8 #Attr.2;
-    ret Str.266;
+    let Str.280 : List U8 = lowlevel StrToUtf8 #Attr.2;
+    ret Str.280;
 
 procedure Str.48 (#Attr.2, #Attr.3, #Attr.4):
-    let Str.260 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
-    ret Str.260;
+    let Str.274 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
+    ret Str.274;
 
-procedure Str.9 (Str.73):
-    let Str.258 : U64 = 0i64;
-    let Str.259 : U64 = CallByName List.6 Str.73;
-    let Str.74 : {U64, Str, Int1, U8} = CallByName Str.48 Str.73 Str.258 Str.259;
-    let Str.255 : Int1 = StructAtIndex 2 Str.74;
-    if Str.255 then
-        let Str.257 : Str = StructAtIndex 1 Str.74;
-        inc Str.257;
-        dec Str.74;
-        let Str.256 : [C {U64, U8}, C Str] = TagId(1) Str.257;
-        ret Str.256;
+procedure Str.9 (Str.76):
+    let Str.272 : U64 = 0i64;
+    let Str.273 : U64 = CallByName List.6 Str.76;
+    let Str.77 : {U64, Str, Int1, U8} = CallByName Str.48 Str.76 Str.272 Str.273;
+    let Str.269 : Int1 = StructAtIndex 2 Str.77;
+    if Str.269 then
+        let Str.271 : Str = StructAtIndex 1 Str.77;
+        inc Str.271;
+        dec Str.77;
+        let Str.270 : [C {U64, U8}, C Str] = TagId(1) Str.271;
+        ret Str.270;
     else
-        let Str.253 : U8 = StructAtIndex 3 Str.74;
-        let Str.254 : U64 = StructAtIndex 0 Str.74;
-        dec Str.74;
-        let Str.252 : {U64, U8} = Struct {Str.254, Str.253};
-        let Str.251 : [C {U64, U8}, C Str] = TagId(0) Str.252;
-        ret Str.251;
+        let Str.267 : U8 = StructAtIndex 3 Str.77;
+        let Str.268 : U64 = StructAtIndex 0 Str.77;
+        dec Str.77;
+        let Str.266 : {U64, U8} = Struct {Str.268, Str.267};
+        let Str.265 : [C {U64, U8}, C Str] = TagId(0) Str.266;
+        ret Str.265;
 
 procedure Test.0 ():
     let Test.11 : Str = "foo";
diff --git a/crates/compiler/test_mono/generated/encode_derived_record_two_field_strings.txt b/crates/compiler/test_mono/generated/encode_derived_record_two_field_strings.txt
index c40b1c595e..faa8c35dcf 100644
--- a/crates/compiler/test_mono/generated/encode_derived_record_two_field_strings.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_record_two_field_strings.txt
@@ -33,11 +33,11 @@ procedure Encode.23 (Encode.94, Encode.102, Encode.96):
     ret Encode.106;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.113 : List U8 = CallByName Json.113 Encode.94 Encode.96 Encode.102;
+    let Encode.113 : List U8 = CallByName Json.112 Encode.94 Encode.96 Encode.102;
     ret Encode.113;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.117 : List U8 = CallByName Json.97 Encode.94 Encode.96 Encode.102;
+    let Encode.117 : List U8 = CallByName Json.96 Encode.94 Encode.96 Encode.102;
     ret Encode.117;
 
 procedure Encode.25 (Encode.100, Encode.101):
@@ -47,188 +47,188 @@ procedure Encode.25 (Encode.100, Encode.101):
     ret Encode.103;
 
 procedure Json.1 ():
-    let Json.396 : {} = Struct {};
-    ret Json.396;
+    let Json.394 : {} = Struct {};
+    ret Json.394;
 
-procedure Json.113 (Json.114, Json.399, Json.112):
-    let Json.432 : I32 = 123i64;
-    let Json.431 : U8 = CallByName Num.123 Json.432;
-    let Json.116 : List U8 = CallByName List.4 Json.114 Json.431;
-    let Json.430 : U64 = CallByName List.6 Json.112;
-    let Json.407 : {List U8, U64} = Struct {Json.116, Json.430};
-    let Json.408 : {} = Struct {};
-    let Json.406 : {List U8, U64} = CallByName List.18 Json.112 Json.407 Json.408;
-    dec Json.112;
-    let Json.118 : List U8 = StructAtIndex 0 Json.406;
-    inc Json.118;
-    dec Json.406;
-    let Json.405 : I32 = 125i64;
-    let Json.404 : U8 = CallByName Num.123 Json.405;
-    let Json.403 : List U8 = CallByName List.4 Json.118 Json.404;
-    ret Json.403;
+procedure Json.112 (Json.113, Json.397, Json.111):
+    let Json.430 : I64 = 123i64;
+    let Json.429 : U8 = CallByName Num.125 Json.430;
+    let Json.115 : List U8 = CallByName List.4 Json.113 Json.429;
+    let Json.428 : U64 = CallByName List.6 Json.111;
+    let Json.405 : {List U8, U64} = Struct {Json.115, Json.428};
+    let Json.406 : {} = Struct {};
+    let Json.404 : {List U8, U64} = CallByName List.18 Json.111 Json.405 Json.406;
+    dec Json.111;
+    let Json.117 : List U8 = StructAtIndex 0 Json.404;
+    inc Json.117;
+    dec Json.404;
+    let Json.403 : I64 = 125i64;
+    let Json.402 : U8 = CallByName Num.125 Json.403;
+    let Json.401 : List U8 = CallByName List.4 Json.117 Json.402;
+    ret Json.401;
 
-procedure Json.115 (Json.401, Json.402):
-    let Json.121 : Str = StructAtIndex 0 Json.402;
+procedure Json.114 (Json.399, Json.400):
+    let Json.120 : Str = StructAtIndex 0 Json.400;
+    inc Json.120;
+    let Json.121 : Str = StructAtIndex 1 Json.400;
     inc Json.121;
-    let Json.122 : Str = StructAtIndex 1 Json.402;
-    inc Json.122;
-    dec Json.402;
-    let Json.119 : List U8 = StructAtIndex 0 Json.401;
-    inc Json.119;
-    let Json.120 : U64 = StructAtIndex 1 Json.401;
-    dec Json.401;
-    let Json.429 : I32 = 34i64;
-    let Json.428 : U8 = CallByName Num.123 Json.429;
-    let Json.426 : List U8 = CallByName List.4 Json.119 Json.428;
-    let Json.427 : List U8 = CallByName Str.12 Json.121;
-    let Json.423 : List U8 = CallByName List.8 Json.426 Json.427;
-    let Json.425 : I32 = 34i64;
-    let Json.424 : U8 = CallByName Num.123 Json.425;
-    let Json.420 : List U8 = CallByName List.4 Json.423 Json.424;
-    let Json.422 : I32 = 58i64;
-    let Json.421 : U8 = CallByName Num.123 Json.422;
-    let Json.418 : List U8 = CallByName List.4 Json.420 Json.421;
-    let Json.419 : {} = Struct {};
-    let Json.123 : List U8 = CallByName Encode.23 Json.418 Json.122 Json.419;
-    joinpoint Json.413 Json.124:
-        let Json.411 : U64 = 1i64;
-        let Json.410 : U64 = CallByName Num.20 Json.120 Json.411;
-        let Json.409 : {List U8, U64} = Struct {Json.124, Json.410};
-        ret Json.409;
+    dec Json.400;
+    let Json.118 : List U8 = StructAtIndex 0 Json.399;
+    inc Json.118;
+    let Json.119 : U64 = StructAtIndex 1 Json.399;
+    dec Json.399;
+    let Json.427 : I64 = 34i64;
+    let Json.426 : U8 = CallByName Num.125 Json.427;
+    let Json.424 : List U8 = CallByName List.4 Json.118 Json.426;
+    let Json.425 : List U8 = CallByName Str.12 Json.120;
+    let Json.421 : List U8 = CallByName List.8 Json.424 Json.425;
+    let Json.423 : I64 = 34i64;
+    let Json.422 : U8 = CallByName Num.125 Json.423;
+    let Json.418 : List U8 = CallByName List.4 Json.421 Json.422;
+    let Json.420 : I64 = 58i64;
+    let Json.419 : U8 = CallByName Num.125 Json.420;
+    let Json.416 : List U8 = CallByName List.4 Json.418 Json.419;
+    let Json.417 : {} = Struct {};
+    let Json.122 : List U8 = CallByName Encode.23 Json.416 Json.121 Json.417;
+    joinpoint Json.411 Json.123:
+        let Json.409 : U64 = 1i64;
+        let Json.408 : U64 = CallByName Num.20 Json.119 Json.409;
+        let Json.407 : {List U8, U64} = Struct {Json.123, Json.408};
+        ret Json.407;
     in
-    let Json.417 : U64 = 1i64;
-    let Json.414 : Int1 = CallByName Num.24 Json.120 Json.417;
-    if Json.414 then
-        let Json.416 : I32 = 44i64;
-        let Json.415 : U8 = CallByName Num.123 Json.416;
-        let Json.412 : List U8 = CallByName List.4 Json.123 Json.415;
-        jump Json.413 Json.412;
+    let Json.415 : U64 = 1i64;
+    let Json.412 : Int1 = CallByName Num.24 Json.119 Json.415;
+    if Json.412 then
+        let Json.414 : I64 = 44i64;
+        let Json.413 : U8 = CallByName Num.125 Json.414;
+        let Json.410 : List U8 = CallByName List.4 Json.122 Json.413;
+        jump Json.411 Json.410;
     else
-        jump Json.413 Json.123;
+        jump Json.411 Json.122;
 
-procedure Json.18 (Json.96):
-    let Json.445 : Str = CallByName Encode.22 Json.96;
-    ret Json.445;
+procedure Json.18 (Json.95):
+    let Json.443 : Str = CallByName Encode.22 Json.95;
+    ret Json.443;
 
-procedure Json.20 (Json.112):
-    let Json.397 : List {Str, Str} = CallByName Encode.22 Json.112;
-    ret Json.397;
+procedure Json.20 (Json.111):
+    let Json.395 : List {Str, Str} = CallByName Encode.22 Json.111;
+    ret Json.395;
 
-procedure Json.97 (Json.98, Json.435, Json.96):
-    let Json.444 : I32 = 34i64;
-    let Json.443 : U8 = CallByName Num.123 Json.444;
-    let Json.441 : List U8 = CallByName List.4 Json.98 Json.443;
-    let Json.442 : List U8 = CallByName Str.12 Json.96;
-    let Json.438 : List U8 = CallByName List.8 Json.441 Json.442;
-    let Json.440 : I32 = 34i64;
-    let Json.439 : U8 = CallByName Num.123 Json.440;
-    let Json.437 : List U8 = CallByName List.4 Json.438 Json.439;
-    ret Json.437;
+procedure Json.96 (Json.97, Json.433, Json.95):
+    let Json.442 : I64 = 34i64;
+    let Json.441 : U8 = CallByName Num.125 Json.442;
+    let Json.439 : List U8 = CallByName List.4 Json.97 Json.441;
+    let Json.440 : List U8 = CallByName Str.12 Json.95;
+    let Json.436 : List U8 = CallByName List.8 Json.439 Json.440;
+    let Json.438 : I64 = 34i64;
+    let Json.437 : U8 = CallByName Num.125 Json.438;
+    let Json.435 : List U8 = CallByName List.4 Json.436 Json.437;
+    ret Json.435;
 
-procedure List.133 (List.134, List.135, List.132):
-    let List.426 : {List U8, U64} = CallByName Json.115 List.134 List.135;
-    ret List.426;
+procedure List.137 (List.138, List.139, List.136):
+    let List.455 : {List U8, U64} = CallByName Json.114 List.138 List.139;
+    ret List.455;
 
-procedure List.18 (List.130, List.131, List.132):
-    let List.408 : {List U8, U64} = CallByName List.75 List.130 List.131 List.132;
-    ret List.408;
+procedure List.18 (List.134, List.135, List.136):
+    let List.437 : {List U8, U64} = CallByName List.89 List.134 List.135 List.136;
+    ret List.437;
 
-procedure List.4 (List.101, List.102):
-    let List.407 : U64 = 1i64;
-    let List.406 : List U8 = CallByName List.70 List.101 List.407;
-    let List.405 : List U8 = CallByName List.71 List.406 List.102;
-    ret List.405;
+procedure List.4 (List.105, List.106):
+    let List.436 : U64 = 1i64;
+    let List.435 : List U8 = CallByName List.70 List.105 List.436;
+    let List.434 : List U8 = CallByName List.71 List.435 List.106;
+    ret List.434;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.429 : U64 = lowlevel ListLen #Attr.2;
-    ret List.429;
+    let List.458 : U64 = lowlevel ListLen #Attr.2;
+    ret List.458;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.423 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.423;
+    let List.452 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.452;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.386 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.386;
+    let List.415 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.415;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.384 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.384;
-
-procedure List.75 (List.356, List.357, List.358):
-    let List.412 : U64 = 0i64;
-    let List.413 : U64 = CallByName List.6 List.356;
-    let List.411 : {List U8, U64} = CallByName List.86 List.356 List.357 List.358 List.412 List.413;
-    ret List.411;
+    let List.413 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.8 (#Attr.2, #Attr.3):
-    let List.428 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.428;
+    let List.457 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.457;
 
-procedure List.86 (List.439, List.440, List.441, List.442, List.443):
-    joinpoint List.414 List.359 List.360 List.361 List.362 List.363:
-        let List.416 : Int1 = CallByName Num.22 List.362 List.363;
-        if List.416 then
-            let List.422 : {Str, Str} = CallByName List.66 List.359 List.362;
-            let List.417 : {List U8, U64} = CallByName List.133 List.360 List.422 List.361;
-            let List.420 : U64 = 1i64;
-            let List.419 : U64 = CallByName Num.19 List.362 List.420;
-            jump List.414 List.359 List.417 List.361 List.419 List.363;
+procedure List.89 (List.385, List.386, List.387):
+    let List.441 : U64 = 0i64;
+    let List.442 : U64 = CallByName List.6 List.385;
+    let List.440 : {List U8, U64} = CallByName List.90 List.385 List.386 List.387 List.441 List.442;
+    ret List.440;
+
+procedure List.90 (List.468, List.469, List.470, List.471, List.472):
+    joinpoint List.443 List.388 List.389 List.390 List.391 List.392:
+        let List.445 : Int1 = CallByName Num.22 List.391 List.392;
+        if List.445 then
+            let List.451 : {Str, Str} = CallByName List.66 List.388 List.391;
+            let List.446 : {List U8, U64} = CallByName List.137 List.389 List.451 List.390;
+            let List.449 : U64 = 1i64;
+            let List.448 : U64 = CallByName Num.19 List.391 List.449;
+            jump List.443 List.388 List.446 List.390 List.448 List.392;
         else
-            ret List.360;
+            ret List.389;
     in
-    jump List.414 List.439 List.440 List.441 List.442 List.443;
+    jump List.443 List.468 List.469 List.470 List.471 List.472;
 
-procedure Num.123 (#Attr.2):
-    let Num.264 : U8 = lowlevel NumIntCast #Attr.2;
-    ret Num.264;
+procedure Num.125 (#Attr.2):
+    let Num.263 : U8 = lowlevel NumIntCast #Attr.2;
+    ret Num.263;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.267 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.267;
-
-procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.265 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.265;
-
-procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.268 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.268;
-
-procedure Num.24 (#Attr.2, #Attr.3):
-    let Num.266 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    let Num.266 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
     ret Num.266;
 
+procedure Num.20 (#Attr.2, #Attr.3):
+    let Num.264 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.264;
+
+procedure Num.22 (#Attr.2, #Attr.3):
+    let Num.267 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.267;
+
+procedure Num.24 (#Attr.2, #Attr.3):
+    let Num.265 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    ret Num.265;
+
 procedure Str.12 (#Attr.2):
-    let Str.266 : List U8 = lowlevel StrToUtf8 #Attr.2;
-    ret Str.266;
+    let Str.280 : List U8 = lowlevel StrToUtf8 #Attr.2;
+    ret Str.280;
 
 procedure Str.48 (#Attr.2, #Attr.3, #Attr.4):
-    let Str.260 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
-    ret Str.260;
+    let Str.274 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
+    ret Str.274;
 
-procedure Str.9 (Str.73):
-    let Str.258 : U64 = 0i64;
-    let Str.259 : U64 = CallByName List.6 Str.73;
-    let Str.74 : {U64, Str, Int1, U8} = CallByName Str.48 Str.73 Str.258 Str.259;
-    let Str.255 : Int1 = StructAtIndex 2 Str.74;
-    if Str.255 then
-        let Str.257 : Str = StructAtIndex 1 Str.74;
-        inc Str.257;
-        dec Str.74;
-        let Str.256 : [C {U64, U8}, C Str] = TagId(1) Str.257;
-        ret Str.256;
+procedure Str.9 (Str.76):
+    let Str.272 : U64 = 0i64;
+    let Str.273 : U64 = CallByName List.6 Str.76;
+    let Str.77 : {U64, Str, Int1, U8} = CallByName Str.48 Str.76 Str.272 Str.273;
+    let Str.269 : Int1 = StructAtIndex 2 Str.77;
+    if Str.269 then
+        let Str.271 : Str = StructAtIndex 1 Str.77;
+        inc Str.271;
+        dec Str.77;
+        let Str.270 : [C {U64, U8}, C Str] = TagId(1) Str.271;
+        ret Str.270;
     else
-        let Str.253 : U8 = StructAtIndex 3 Str.74;
-        let Str.254 : U64 = StructAtIndex 0 Str.74;
-        dec Str.74;
-        let Str.252 : {U64, U8} = Struct {Str.254, Str.253};
-        let Str.251 : [C {U64, U8}, C Str] = TagId(0) Str.252;
-        ret Str.251;
+        let Str.267 : U8 = StructAtIndex 3 Str.77;
+        let Str.268 : U64 = StructAtIndex 0 Str.77;
+        dec Str.77;
+        let Str.266 : {U64, U8} = Struct {Str.268, Str.267};
+        let Str.265 : [C {U64, U8}, C Str] = TagId(0) Str.266;
+        ret Str.265;
 
 procedure Test.0 ():
     let Test.11 : Str = "foo";
diff --git a/crates/compiler/test_mono/generated/encode_derived_string.txt b/crates/compiler/test_mono/generated/encode_derived_string.txt
index 445fb2415a..922ec7bc09 100644
--- a/crates/compiler/test_mono/generated/encode_derived_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_string.txt
@@ -2,7 +2,7 @@ procedure Encode.22 (Encode.93):
     ret Encode.93;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.106 : List U8 = CallByName Json.97 Encode.94 Encode.96 Encode.102;
+    let Encode.106 : List U8 = CallByName Json.96 Encode.94 Encode.96 Encode.102;
     ret Encode.106;
 
 procedure Encode.25 (Encode.100, Encode.101):
@@ -12,76 +12,76 @@ procedure Encode.25 (Encode.100, Encode.101):
     ret Encode.103;
 
 procedure Json.1 ():
-    let Json.396 : {} = Struct {};
-    ret Json.396;
+    let Json.394 : {} = Struct {};
+    ret Json.394;
 
-procedure Json.18 (Json.96):
-    let Json.397 : Str = CallByName Encode.22 Json.96;
-    ret Json.397;
+procedure Json.18 (Json.95):
+    let Json.395 : Str = CallByName Encode.22 Json.95;
+    ret Json.395;
 
-procedure Json.97 (Json.98, Json.399, Json.96):
-    let Json.408 : I32 = 34i64;
-    let Json.407 : U8 = CallByName Num.123 Json.408;
-    let Json.405 : List U8 = CallByName List.4 Json.98 Json.407;
-    let Json.406 : List U8 = CallByName Str.12 Json.96;
-    let Json.402 : List U8 = CallByName List.8 Json.405 Json.406;
-    let Json.404 : I32 = 34i64;
-    let Json.403 : U8 = CallByName Num.123 Json.404;
-    let Json.401 : List U8 = CallByName List.4 Json.402 Json.403;
-    ret Json.401;
+procedure Json.96 (Json.97, Json.397, Json.95):
+    let Json.406 : I64 = 34i64;
+    let Json.405 : U8 = CallByName Num.125 Json.406;
+    let Json.403 : List U8 = CallByName List.4 Json.97 Json.405;
+    let Json.404 : List U8 = CallByName Str.12 Json.95;
+    let Json.400 : List U8 = CallByName List.8 Json.403 Json.404;
+    let Json.402 : I64 = 34i64;
+    let Json.401 : U8 = CallByName Num.125 Json.402;
+    let Json.399 : List U8 = CallByName List.4 Json.400 Json.401;
+    ret Json.399;
 
-procedure List.4 (List.101, List.102):
-    let List.389 : U64 = 1i64;
-    let List.388 : List U8 = CallByName List.70 List.101 List.389;
-    let List.387 : List U8 = CallByName List.71 List.388 List.102;
-    ret List.387;
+procedure List.4 (List.105, List.106):
+    let List.418 : U64 = 1i64;
+    let List.417 : List U8 = CallByName List.70 List.105 List.418;
+    let List.416 : List U8 = CallByName List.71 List.417 List.106;
+    ret List.416;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.386 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.386;
+    let List.415 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.415;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.384 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.384;
+    let List.413 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.8 (#Attr.2, #Attr.3):
-    let List.390 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.390;
+    let List.419 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.419;
 
-procedure Num.123 (#Attr.2):
-    let Num.258 : U8 = lowlevel NumIntCast #Attr.2;
-    ret Num.258;
+procedure Num.125 (#Attr.2):
+    let Num.257 : U8 = lowlevel NumIntCast #Attr.2;
+    ret Num.257;
 
 procedure Str.12 (#Attr.2):
-    let Str.265 : List U8 = lowlevel StrToUtf8 #Attr.2;
-    ret Str.265;
+    let Str.279 : List U8 = lowlevel StrToUtf8 #Attr.2;
+    ret Str.279;
 
 procedure Str.48 (#Attr.2, #Attr.3, #Attr.4):
-    let Str.260 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
-    ret Str.260;
+    let Str.274 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
+    ret Str.274;
 
-procedure Str.9 (Str.73):
-    let Str.258 : U64 = 0i64;
-    let Str.259 : U64 = CallByName List.6 Str.73;
-    let Str.74 : {U64, Str, Int1, U8} = CallByName Str.48 Str.73 Str.258 Str.259;
-    let Str.255 : Int1 = StructAtIndex 2 Str.74;
-    if Str.255 then
-        let Str.257 : Str = StructAtIndex 1 Str.74;
-        inc Str.257;
-        dec Str.74;
-        let Str.256 : [C {U64, U8}, C Str] = TagId(1) Str.257;
-        ret Str.256;
+procedure Str.9 (Str.76):
+    let Str.272 : U64 = 0i64;
+    let Str.273 : U64 = CallByName List.6 Str.76;
+    let Str.77 : {U64, Str, Int1, U8} = CallByName Str.48 Str.76 Str.272 Str.273;
+    let Str.269 : Int1 = StructAtIndex 2 Str.77;
+    if Str.269 then
+        let Str.271 : Str = StructAtIndex 1 Str.77;
+        inc Str.271;
+        dec Str.77;
+        let Str.270 : [C {U64, U8}, C Str] = TagId(1) Str.271;
+        ret Str.270;
     else
-        let Str.253 : U8 = StructAtIndex 3 Str.74;
-        let Str.254 : U64 = StructAtIndex 0 Str.74;
-        dec Str.74;
-        let Str.252 : {U64, U8} = Struct {Str.254, Str.253};
-        let Str.251 : [C {U64, U8}, C Str] = TagId(0) Str.252;
-        ret Str.251;
+        let Str.267 : U8 = StructAtIndex 3 Str.77;
+        let Str.268 : U64 = StructAtIndex 0 Str.77;
+        dec Str.77;
+        let Str.266 : {U64, U8} = Struct {Str.268, Str.267};
+        let Str.265 : [C {U64, U8}, C Str] = TagId(0) Str.266;
+        ret Str.265;
 
 procedure Test.0 ():
     let Test.9 : Str = "abc";
diff --git a/crates/compiler/test_mono/generated/encode_derived_tag_one_field_string.txt b/crates/compiler/test_mono/generated/encode_derived_tag_one_field_string.txt
index fe61a284f4..d5e22ddb0f 100644
--- a/crates/compiler/test_mono/generated/encode_derived_tag_one_field_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_tag_one_field_string.txt
@@ -27,11 +27,11 @@ procedure Encode.23 (Encode.94, Encode.102, Encode.96):
     ret Encode.106;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.113 : List U8 = CallByName Json.127 Encode.94 Encode.96 Encode.102;
+    let Encode.113 : List U8 = CallByName Json.126 Encode.94 Encode.96 Encode.102;
     ret Encode.113;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.116 : List U8 = CallByName Json.97 Encode.94 Encode.96 Encode.102;
+    let Encode.116 : List U8 = CallByName Json.96 Encode.94 Encode.96 Encode.102;
     ret Encode.116;
 
 procedure Encode.25 (Encode.100, Encode.101):
@@ -41,195 +41,195 @@ procedure Encode.25 (Encode.100, Encode.101):
     ret Encode.103;
 
 procedure Json.1 ():
-    let Json.396 : {} = Struct {};
-    ret Json.396;
+    let Json.394 : {} = Struct {};
+    ret Json.394;
 
-procedure Json.127 (Json.128, Json.399, #Attr.12):
-    let Json.126 : List Str = StructAtIndex 1 #Attr.12;
-    inc Json.126;
-    let Json.125 : Str = StructAtIndex 0 #Attr.12;
+procedure Json.126 (Json.127, Json.397, #Attr.12):
+    let Json.125 : List Str = StructAtIndex 1 #Attr.12;
     inc Json.125;
+    let Json.124 : Str = StructAtIndex 0 #Attr.12;
+    inc Json.124;
     dec #Attr.12;
-    let Json.437 : I32 = 123i64;
-    let Json.436 : U8 = CallByName Num.123 Json.437;
-    let Json.433 : List U8 = CallByName List.4 Json.128 Json.436;
-    let Json.435 : I32 = 34i64;
-    let Json.434 : U8 = CallByName Num.123 Json.435;
-    let Json.431 : List U8 = CallByName List.4 Json.433 Json.434;
-    let Json.432 : List U8 = CallByName Str.12 Json.125;
-    let Json.428 : List U8 = CallByName List.8 Json.431 Json.432;
-    let Json.430 : I32 = 34i64;
-    let Json.429 : U8 = CallByName Num.123 Json.430;
-    let Json.425 : List U8 = CallByName List.4 Json.428 Json.429;
-    let Json.427 : I32 = 58i64;
-    let Json.426 : U8 = CallByName Num.123 Json.427;
-    let Json.422 : List U8 = CallByName List.4 Json.425 Json.426;
-    let Json.424 : I32 = 91i64;
-    let Json.423 : U8 = CallByName Num.123 Json.424;
-    let Json.130 : List U8 = CallByName List.4 Json.422 Json.423;
-    let Json.421 : U64 = CallByName List.6 Json.126;
-    let Json.409 : {List U8, U64} = Struct {Json.130, Json.421};
-    let Json.410 : {} = Struct {};
-    let Json.408 : {List U8, U64} = CallByName List.18 Json.126 Json.409 Json.410;
-    dec Json.126;
-    let Json.132 : List U8 = StructAtIndex 0 Json.408;
+    let Json.435 : I64 = 123i64;
+    let Json.434 : U8 = CallByName Num.125 Json.435;
+    let Json.431 : List U8 = CallByName List.4 Json.127 Json.434;
+    let Json.433 : I64 = 34i64;
+    let Json.432 : U8 = CallByName Num.125 Json.433;
+    let Json.429 : List U8 = CallByName List.4 Json.431 Json.432;
+    let Json.430 : List U8 = CallByName Str.12 Json.124;
+    let Json.426 : List U8 = CallByName List.8 Json.429 Json.430;
+    let Json.428 : I64 = 34i64;
+    let Json.427 : U8 = CallByName Num.125 Json.428;
+    let Json.423 : List U8 = CallByName List.4 Json.426 Json.427;
+    let Json.425 : I64 = 58i64;
+    let Json.424 : U8 = CallByName Num.125 Json.425;
+    let Json.420 : List U8 = CallByName List.4 Json.423 Json.424;
+    let Json.422 : I64 = 91i64;
+    let Json.421 : U8 = CallByName Num.125 Json.422;
+    let Json.129 : List U8 = CallByName List.4 Json.420 Json.421;
+    let Json.419 : U64 = CallByName List.6 Json.125;
+    let Json.407 : {List U8, U64} = Struct {Json.129, Json.419};
+    let Json.408 : {} = Struct {};
+    let Json.406 : {List U8, U64} = CallByName List.18 Json.125 Json.407 Json.408;
+    dec Json.125;
+    let Json.131 : List U8 = StructAtIndex 0 Json.406;
+    inc Json.131;
+    dec Json.406;
+    let Json.405 : I64 = 93i64;
+    let Json.404 : U8 = CallByName Num.125 Json.405;
+    let Json.401 : List U8 = CallByName List.4 Json.131 Json.404;
+    let Json.403 : I64 = 125i64;
+    let Json.402 : U8 = CallByName Num.125 Json.403;
+    let Json.400 : List U8 = CallByName List.4 Json.401 Json.402;
+    ret Json.400;
+
+procedure Json.128 (Json.399, Json.134):
+    let Json.132 : List U8 = StructAtIndex 0 Json.399;
     inc Json.132;
-    dec Json.408;
-    let Json.407 : I32 = 93i64;
-    let Json.406 : U8 = CallByName Num.123 Json.407;
-    let Json.403 : List U8 = CallByName List.4 Json.132 Json.406;
-    let Json.405 : I32 = 125i64;
-    let Json.404 : U8 = CallByName Num.123 Json.405;
-    let Json.402 : List U8 = CallByName List.4 Json.403 Json.404;
-    ret Json.402;
-
-procedure Json.129 (Json.401, Json.135):
-    let Json.133 : List U8 = StructAtIndex 0 Json.401;
-    inc Json.133;
-    let Json.134 : U64 = StructAtIndex 1 Json.401;
-    dec Json.401;
-    let Json.420 : {} = Struct {};
-    let Json.136 : List U8 = CallByName Encode.23 Json.133 Json.135 Json.420;
-    joinpoint Json.415 Json.137:
-        let Json.413 : U64 = 1i64;
-        let Json.412 : U64 = CallByName Num.20 Json.134 Json.413;
-        let Json.411 : {List U8, U64} = Struct {Json.137, Json.412};
-        ret Json.411;
+    let Json.133 : U64 = StructAtIndex 1 Json.399;
+    dec Json.399;
+    let Json.418 : {} = Struct {};
+    let Json.135 : List U8 = CallByName Encode.23 Json.132 Json.134 Json.418;
+    joinpoint Json.413 Json.136:
+        let Json.411 : U64 = 1i64;
+        let Json.410 : U64 = CallByName Num.20 Json.133 Json.411;
+        let Json.409 : {List U8, U64} = Struct {Json.136, Json.410};
+        ret Json.409;
     in
-    let Json.419 : U64 = 1i64;
-    let Json.416 : Int1 = CallByName Num.24 Json.134 Json.419;
-    if Json.416 then
-        let Json.418 : I32 = 44i64;
-        let Json.417 : U8 = CallByName Num.123 Json.418;
-        let Json.414 : List U8 = CallByName List.4 Json.136 Json.417;
-        jump Json.415 Json.414;
+    let Json.417 : U64 = 1i64;
+    let Json.414 : Int1 = CallByName Num.24 Json.133 Json.417;
+    if Json.414 then
+        let Json.416 : I64 = 44i64;
+        let Json.415 : U8 = CallByName Num.125 Json.416;
+        let Json.412 : List U8 = CallByName List.4 Json.135 Json.415;
+        jump Json.413 Json.412;
     else
-        jump Json.415 Json.136;
+        jump Json.413 Json.135;
 
-procedure Json.18 (Json.96):
-    let Json.438 : Str = CallByName Encode.22 Json.96;
-    ret Json.438;
+procedure Json.18 (Json.95):
+    let Json.436 : Str = CallByName Encode.22 Json.95;
+    ret Json.436;
 
-procedure Json.21 (Json.125, Json.126):
-    let Json.398 : {Str, List Str} = Struct {Json.125, Json.126};
-    let Json.397 : {Str, List Str} = CallByName Encode.22 Json.398;
-    ret Json.397;
+procedure Json.21 (Json.124, Json.125):
+    let Json.396 : {Str, List Str} = Struct {Json.124, Json.125};
+    let Json.395 : {Str, List Str} = CallByName Encode.22 Json.396;
+    ret Json.395;
 
-procedure Json.97 (Json.98, Json.440, Json.96):
-    let Json.449 : I32 = 34i64;
-    let Json.448 : U8 = CallByName Num.123 Json.449;
-    let Json.446 : List U8 = CallByName List.4 Json.98 Json.448;
-    let Json.447 : List U8 = CallByName Str.12 Json.96;
-    let Json.443 : List U8 = CallByName List.8 Json.446 Json.447;
-    let Json.445 : I32 = 34i64;
-    let Json.444 : U8 = CallByName Num.123 Json.445;
-    let Json.442 : List U8 = CallByName List.4 Json.443 Json.444;
-    ret Json.442;
+procedure Json.96 (Json.97, Json.438, Json.95):
+    let Json.447 : I64 = 34i64;
+    let Json.446 : U8 = CallByName Num.125 Json.447;
+    let Json.444 : List U8 = CallByName List.4 Json.97 Json.446;
+    let Json.445 : List U8 = CallByName Str.12 Json.95;
+    let Json.441 : List U8 = CallByName List.8 Json.444 Json.445;
+    let Json.443 : I64 = 34i64;
+    let Json.442 : U8 = CallByName Num.125 Json.443;
+    let Json.440 : List U8 = CallByName List.4 Json.441 Json.442;
+    ret Json.440;
 
-procedure List.133 (List.134, List.135, List.132):
-    let List.432 : {List U8, U64} = CallByName Json.129 List.134 List.135;
-    ret List.432;
+procedure List.137 (List.138, List.139, List.136):
+    let List.461 : {List U8, U64} = CallByName Json.128 List.138 List.139;
+    ret List.461;
 
-procedure List.18 (List.130, List.131, List.132):
-    let List.414 : {List U8, U64} = CallByName List.75 List.130 List.131 List.132;
-    ret List.414;
+procedure List.18 (List.134, List.135, List.136):
+    let List.443 : {List U8, U64} = CallByName List.89 List.134 List.135 List.136;
+    ret List.443;
 
-procedure List.4 (List.101, List.102):
-    let List.413 : U64 = 1i64;
-    let List.412 : List U8 = CallByName List.70 List.101 List.413;
-    let List.411 : List U8 = CallByName List.71 List.412 List.102;
-    ret List.411;
+procedure List.4 (List.105, List.106):
+    let List.442 : U64 = 1i64;
+    let List.441 : List U8 = CallByName List.70 List.105 List.442;
+    let List.440 : List U8 = CallByName List.71 List.441 List.106;
+    ret List.440;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.433 : U64 = lowlevel ListLen #Attr.2;
-    ret List.433;
+    let List.462 : U64 = lowlevel ListLen #Attr.2;
+    ret List.462;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.429 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.429;
+    let List.458 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.458;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.386 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.386;
+    let List.415 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.415;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.384 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.384;
-
-procedure List.75 (List.356, List.357, List.358):
-    let List.418 : U64 = 0i64;
-    let List.419 : U64 = CallByName List.6 List.356;
-    let List.417 : {List U8, U64} = CallByName List.86 List.356 List.357 List.358 List.418 List.419;
-    ret List.417;
+    let List.413 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.8 (#Attr.2, #Attr.3):
-    let List.435 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.435;
+    let List.464 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.464;
 
-procedure List.86 (List.445, List.446, List.447, List.448, List.449):
-    joinpoint List.420 List.359 List.360 List.361 List.362 List.363:
-        let List.422 : Int1 = CallByName Num.22 List.362 List.363;
-        if List.422 then
-            let List.428 : Str = CallByName List.66 List.359 List.362;
-            let List.423 : {List U8, U64} = CallByName List.133 List.360 List.428 List.361;
-            let List.426 : U64 = 1i64;
-            let List.425 : U64 = CallByName Num.19 List.362 List.426;
-            jump List.420 List.359 List.423 List.361 List.425 List.363;
+procedure List.89 (List.385, List.386, List.387):
+    let List.447 : U64 = 0i64;
+    let List.448 : U64 = CallByName List.6 List.385;
+    let List.446 : {List U8, U64} = CallByName List.90 List.385 List.386 List.387 List.447 List.448;
+    ret List.446;
+
+procedure List.90 (List.474, List.475, List.476, List.477, List.478):
+    joinpoint List.449 List.388 List.389 List.390 List.391 List.392:
+        let List.451 : Int1 = CallByName Num.22 List.391 List.392;
+        if List.451 then
+            let List.457 : Str = CallByName List.66 List.388 List.391;
+            let List.452 : {List U8, U64} = CallByName List.137 List.389 List.457 List.390;
+            let List.455 : U64 = 1i64;
+            let List.454 : U64 = CallByName Num.19 List.391 List.455;
+            jump List.449 List.388 List.452 List.390 List.454 List.392;
         else
-            ret List.360;
+            ret List.389;
     in
-    jump List.420 List.445 List.446 List.447 List.448 List.449;
+    jump List.449 List.474 List.475 List.476 List.477 List.478;
 
-procedure Num.123 (#Attr.2):
-    let Num.266 : U8 = lowlevel NumIntCast #Attr.2;
-    ret Num.266;
+procedure Num.125 (#Attr.2):
+    let Num.265 : U8 = lowlevel NumIntCast #Attr.2;
+    ret Num.265;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.269 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.269;
-
-procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.267 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.267;
-
-procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.270 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.270;
-
-procedure Num.24 (#Attr.2, #Attr.3):
-    let Num.268 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    let Num.268 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
     ret Num.268;
 
+procedure Num.20 (#Attr.2, #Attr.3):
+    let Num.266 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.266;
+
+procedure Num.22 (#Attr.2, #Attr.3):
+    let Num.269 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.269;
+
+procedure Num.24 (#Attr.2, #Attr.3):
+    let Num.267 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    ret Num.267;
+
 procedure Str.12 (#Attr.2):
-    let Str.266 : List U8 = lowlevel StrToUtf8 #Attr.2;
-    ret Str.266;
+    let Str.280 : List U8 = lowlevel StrToUtf8 #Attr.2;
+    ret Str.280;
 
 procedure Str.48 (#Attr.2, #Attr.3, #Attr.4):
-    let Str.260 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
-    ret Str.260;
+    let Str.274 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
+    ret Str.274;
 
-procedure Str.9 (Str.73):
-    let Str.258 : U64 = 0i64;
-    let Str.259 : U64 = CallByName List.6 Str.73;
-    let Str.74 : {U64, Str, Int1, U8} = CallByName Str.48 Str.73 Str.258 Str.259;
-    let Str.255 : Int1 = StructAtIndex 2 Str.74;
-    if Str.255 then
-        let Str.257 : Str = StructAtIndex 1 Str.74;
-        inc Str.257;
-        dec Str.74;
-        let Str.256 : [C {U64, U8}, C Str] = TagId(1) Str.257;
-        ret Str.256;
+procedure Str.9 (Str.76):
+    let Str.272 : U64 = 0i64;
+    let Str.273 : U64 = CallByName List.6 Str.76;
+    let Str.77 : {U64, Str, Int1, U8} = CallByName Str.48 Str.76 Str.272 Str.273;
+    let Str.269 : Int1 = StructAtIndex 2 Str.77;
+    if Str.269 then
+        let Str.271 : Str = StructAtIndex 1 Str.77;
+        inc Str.271;
+        dec Str.77;
+        let Str.270 : [C {U64, U8}, C Str] = TagId(1) Str.271;
+        ret Str.270;
     else
-        let Str.253 : U8 = StructAtIndex 3 Str.74;
-        let Str.254 : U64 = StructAtIndex 0 Str.74;
-        dec Str.74;
-        let Str.252 : {U64, U8} = Struct {Str.254, Str.253};
-        let Str.251 : [C {U64, U8}, C Str] = TagId(0) Str.252;
-        ret Str.251;
+        let Str.267 : U8 = StructAtIndex 3 Str.77;
+        let Str.268 : U64 = StructAtIndex 0 Str.77;
+        dec Str.77;
+        let Str.266 : {U64, U8} = Struct {Str.268, Str.267};
+        let Str.265 : [C {U64, U8}, C Str] = TagId(0) Str.266;
+        ret Str.265;
 
 procedure Test.0 ():
     let Test.12 : Str = "foo";
diff --git a/crates/compiler/test_mono/generated/encode_derived_tag_two_payloads_string.txt b/crates/compiler/test_mono/generated/encode_derived_tag_two_payloads_string.txt
index 0fba32c529..39d9458331 100644
--- a/crates/compiler/test_mono/generated/encode_derived_tag_two_payloads_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_tag_two_payloads_string.txt
@@ -33,11 +33,11 @@ procedure Encode.23 (Encode.94, Encode.102, Encode.96):
     ret Encode.106;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.113 : List U8 = CallByName Json.127 Encode.94 Encode.96 Encode.102;
+    let Encode.113 : List U8 = CallByName Json.126 Encode.94 Encode.96 Encode.102;
     ret Encode.113;
 
 procedure Encode.23 (Encode.94, Encode.102, Encode.96):
-    let Encode.117 : List U8 = CallByName Json.97 Encode.94 Encode.96 Encode.102;
+    let Encode.117 : List U8 = CallByName Json.96 Encode.94 Encode.96 Encode.102;
     ret Encode.117;
 
 procedure Encode.25 (Encode.100, Encode.101):
@@ -47,195 +47,195 @@ procedure Encode.25 (Encode.100, Encode.101):
     ret Encode.103;
 
 procedure Json.1 ():
-    let Json.396 : {} = Struct {};
-    ret Json.396;
+    let Json.394 : {} = Struct {};
+    ret Json.394;
 
-procedure Json.127 (Json.128, Json.399, #Attr.12):
-    let Json.126 : List Str = StructAtIndex 1 #Attr.12;
-    inc Json.126;
-    let Json.125 : Str = StructAtIndex 0 #Attr.12;
+procedure Json.126 (Json.127, Json.397, #Attr.12):
+    let Json.125 : List Str = StructAtIndex 1 #Attr.12;
     inc Json.125;
+    let Json.124 : Str = StructAtIndex 0 #Attr.12;
+    inc Json.124;
     dec #Attr.12;
-    let Json.437 : I32 = 123i64;
-    let Json.436 : U8 = CallByName Num.123 Json.437;
-    let Json.433 : List U8 = CallByName List.4 Json.128 Json.436;
-    let Json.435 : I32 = 34i64;
-    let Json.434 : U8 = CallByName Num.123 Json.435;
-    let Json.431 : List U8 = CallByName List.4 Json.433 Json.434;
-    let Json.432 : List U8 = CallByName Str.12 Json.125;
-    let Json.428 : List U8 = CallByName List.8 Json.431 Json.432;
-    let Json.430 : I32 = 34i64;
-    let Json.429 : U8 = CallByName Num.123 Json.430;
-    let Json.425 : List U8 = CallByName List.4 Json.428 Json.429;
-    let Json.427 : I32 = 58i64;
-    let Json.426 : U8 = CallByName Num.123 Json.427;
-    let Json.422 : List U8 = CallByName List.4 Json.425 Json.426;
-    let Json.424 : I32 = 91i64;
-    let Json.423 : U8 = CallByName Num.123 Json.424;
-    let Json.130 : List U8 = CallByName List.4 Json.422 Json.423;
-    let Json.421 : U64 = CallByName List.6 Json.126;
-    let Json.409 : {List U8, U64} = Struct {Json.130, Json.421};
-    let Json.410 : {} = Struct {};
-    let Json.408 : {List U8, U64} = CallByName List.18 Json.126 Json.409 Json.410;
-    dec Json.126;
-    let Json.132 : List U8 = StructAtIndex 0 Json.408;
+    let Json.435 : I64 = 123i64;
+    let Json.434 : U8 = CallByName Num.125 Json.435;
+    let Json.431 : List U8 = CallByName List.4 Json.127 Json.434;
+    let Json.433 : I64 = 34i64;
+    let Json.432 : U8 = CallByName Num.125 Json.433;
+    let Json.429 : List U8 = CallByName List.4 Json.431 Json.432;
+    let Json.430 : List U8 = CallByName Str.12 Json.124;
+    let Json.426 : List U8 = CallByName List.8 Json.429 Json.430;
+    let Json.428 : I64 = 34i64;
+    let Json.427 : U8 = CallByName Num.125 Json.428;
+    let Json.423 : List U8 = CallByName List.4 Json.426 Json.427;
+    let Json.425 : I64 = 58i64;
+    let Json.424 : U8 = CallByName Num.125 Json.425;
+    let Json.420 : List U8 = CallByName List.4 Json.423 Json.424;
+    let Json.422 : I64 = 91i64;
+    let Json.421 : U8 = CallByName Num.125 Json.422;
+    let Json.129 : List U8 = CallByName List.4 Json.420 Json.421;
+    let Json.419 : U64 = CallByName List.6 Json.125;
+    let Json.407 : {List U8, U64} = Struct {Json.129, Json.419};
+    let Json.408 : {} = Struct {};
+    let Json.406 : {List U8, U64} = CallByName List.18 Json.125 Json.407 Json.408;
+    dec Json.125;
+    let Json.131 : List U8 = StructAtIndex 0 Json.406;
+    inc Json.131;
+    dec Json.406;
+    let Json.405 : I64 = 93i64;
+    let Json.404 : U8 = CallByName Num.125 Json.405;
+    let Json.401 : List U8 = CallByName List.4 Json.131 Json.404;
+    let Json.403 : I64 = 125i64;
+    let Json.402 : U8 = CallByName Num.125 Json.403;
+    let Json.400 : List U8 = CallByName List.4 Json.401 Json.402;
+    ret Json.400;
+
+procedure Json.128 (Json.399, Json.134):
+    let Json.132 : List U8 = StructAtIndex 0 Json.399;
     inc Json.132;
-    dec Json.408;
-    let Json.407 : I32 = 93i64;
-    let Json.406 : U8 = CallByName Num.123 Json.407;
-    let Json.403 : List U8 = CallByName List.4 Json.132 Json.406;
-    let Json.405 : I32 = 125i64;
-    let Json.404 : U8 = CallByName Num.123 Json.405;
-    let Json.402 : List U8 = CallByName List.4 Json.403 Json.404;
-    ret Json.402;
-
-procedure Json.129 (Json.401, Json.135):
-    let Json.133 : List U8 = StructAtIndex 0 Json.401;
-    inc Json.133;
-    let Json.134 : U64 = StructAtIndex 1 Json.401;
-    dec Json.401;
-    let Json.420 : {} = Struct {};
-    let Json.136 : List U8 = CallByName Encode.23 Json.133 Json.135 Json.420;
-    joinpoint Json.415 Json.137:
-        let Json.413 : U64 = 1i64;
-        let Json.412 : U64 = CallByName Num.20 Json.134 Json.413;
-        let Json.411 : {List U8, U64} = Struct {Json.137, Json.412};
-        ret Json.411;
+    let Json.133 : U64 = StructAtIndex 1 Json.399;
+    dec Json.399;
+    let Json.418 : {} = Struct {};
+    let Json.135 : List U8 = CallByName Encode.23 Json.132 Json.134 Json.418;
+    joinpoint Json.413 Json.136:
+        let Json.411 : U64 = 1i64;
+        let Json.410 : U64 = CallByName Num.20 Json.133 Json.411;
+        let Json.409 : {List U8, U64} = Struct {Json.136, Json.410};
+        ret Json.409;
     in
-    let Json.419 : U64 = 1i64;
-    let Json.416 : Int1 = CallByName Num.24 Json.134 Json.419;
-    if Json.416 then
-        let Json.418 : I32 = 44i64;
-        let Json.417 : U8 = CallByName Num.123 Json.418;
-        let Json.414 : List U8 = CallByName List.4 Json.136 Json.417;
-        jump Json.415 Json.414;
+    let Json.417 : U64 = 1i64;
+    let Json.414 : Int1 = CallByName Num.24 Json.133 Json.417;
+    if Json.414 then
+        let Json.416 : I64 = 44i64;
+        let Json.415 : U8 = CallByName Num.125 Json.416;
+        let Json.412 : List U8 = CallByName List.4 Json.135 Json.415;
+        jump Json.413 Json.412;
     else
-        jump Json.415 Json.136;
+        jump Json.413 Json.135;
 
-procedure Json.18 (Json.96):
-    let Json.450 : Str = CallByName Encode.22 Json.96;
-    ret Json.450;
+procedure Json.18 (Json.95):
+    let Json.448 : Str = CallByName Encode.22 Json.95;
+    ret Json.448;
 
-procedure Json.21 (Json.125, Json.126):
-    let Json.398 : {Str, List Str} = Struct {Json.125, Json.126};
-    let Json.397 : {Str, List Str} = CallByName Encode.22 Json.398;
-    ret Json.397;
+procedure Json.21 (Json.124, Json.125):
+    let Json.396 : {Str, List Str} = Struct {Json.124, Json.125};
+    let Json.395 : {Str, List Str} = CallByName Encode.22 Json.396;
+    ret Json.395;
 
-procedure Json.97 (Json.98, Json.440, Json.96):
-    let Json.449 : I32 = 34i64;
-    let Json.448 : U8 = CallByName Num.123 Json.449;
-    let Json.446 : List U8 = CallByName List.4 Json.98 Json.448;
-    let Json.447 : List U8 = CallByName Str.12 Json.96;
-    let Json.443 : List U8 = CallByName List.8 Json.446 Json.447;
-    let Json.445 : I32 = 34i64;
-    let Json.444 : U8 = CallByName Num.123 Json.445;
-    let Json.442 : List U8 = CallByName List.4 Json.443 Json.444;
-    ret Json.442;
+procedure Json.96 (Json.97, Json.438, Json.95):
+    let Json.447 : I64 = 34i64;
+    let Json.446 : U8 = CallByName Num.125 Json.447;
+    let Json.444 : List U8 = CallByName List.4 Json.97 Json.446;
+    let Json.445 : List U8 = CallByName Str.12 Json.95;
+    let Json.441 : List U8 = CallByName List.8 Json.444 Json.445;
+    let Json.443 : I64 = 34i64;
+    let Json.442 : U8 = CallByName Num.125 Json.443;
+    let Json.440 : List U8 = CallByName List.4 Json.441 Json.442;
+    ret Json.440;
 
-procedure List.133 (List.134, List.135, List.132):
-    let List.432 : {List U8, U64} = CallByName Json.129 List.134 List.135;
-    ret List.432;
+procedure List.137 (List.138, List.139, List.136):
+    let List.461 : {List U8, U64} = CallByName Json.128 List.138 List.139;
+    ret List.461;
 
-procedure List.18 (List.130, List.131, List.132):
-    let List.414 : {List U8, U64} = CallByName List.75 List.130 List.131 List.132;
-    ret List.414;
+procedure List.18 (List.134, List.135, List.136):
+    let List.443 : {List U8, U64} = CallByName List.89 List.134 List.135 List.136;
+    ret List.443;
 
-procedure List.4 (List.101, List.102):
-    let List.413 : U64 = 1i64;
-    let List.412 : List U8 = CallByName List.70 List.101 List.413;
-    let List.411 : List U8 = CallByName List.71 List.412 List.102;
-    ret List.411;
+procedure List.4 (List.105, List.106):
+    let List.442 : U64 = 1i64;
+    let List.441 : List U8 = CallByName List.70 List.105 List.442;
+    let List.440 : List U8 = CallByName List.71 List.441 List.106;
+    ret List.440;
 
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.433 : U64 = lowlevel ListLen #Attr.2;
-    ret List.433;
+    let List.462 : U64 = lowlevel ListLen #Attr.2;
+    ret List.462;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.429 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.429;
+    let List.458 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.458;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.386 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.386;
+    let List.415 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.415;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.384 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.384;
-
-procedure List.75 (List.356, List.357, List.358):
-    let List.418 : U64 = 0i64;
-    let List.419 : U64 = CallByName List.6 List.356;
-    let List.417 : {List U8, U64} = CallByName List.86 List.356 List.357 List.358 List.418 List.419;
-    ret List.417;
+    let List.413 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.8 (#Attr.2, #Attr.3):
-    let List.435 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.435;
+    let List.464 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.464;
 
-procedure List.86 (List.445, List.446, List.447, List.448, List.449):
-    joinpoint List.420 List.359 List.360 List.361 List.362 List.363:
-        let List.422 : Int1 = CallByName Num.22 List.362 List.363;
-        if List.422 then
-            let List.428 : Str = CallByName List.66 List.359 List.362;
-            let List.423 : {List U8, U64} = CallByName List.133 List.360 List.428 List.361;
-            let List.426 : U64 = 1i64;
-            let List.425 : U64 = CallByName Num.19 List.362 List.426;
-            jump List.420 List.359 List.423 List.361 List.425 List.363;
+procedure List.89 (List.385, List.386, List.387):
+    let List.447 : U64 = 0i64;
+    let List.448 : U64 = CallByName List.6 List.385;
+    let List.446 : {List U8, U64} = CallByName List.90 List.385 List.386 List.387 List.447 List.448;
+    ret List.446;
+
+procedure List.90 (List.474, List.475, List.476, List.477, List.478):
+    joinpoint List.449 List.388 List.389 List.390 List.391 List.392:
+        let List.451 : Int1 = CallByName Num.22 List.391 List.392;
+        if List.451 then
+            let List.457 : Str = CallByName List.66 List.388 List.391;
+            let List.452 : {List U8, U64} = CallByName List.137 List.389 List.457 List.390;
+            let List.455 : U64 = 1i64;
+            let List.454 : U64 = CallByName Num.19 List.391 List.455;
+            jump List.449 List.388 List.452 List.390 List.454 List.392;
         else
-            ret List.360;
+            ret List.389;
     in
-    jump List.420 List.445 List.446 List.447 List.448 List.449;
+    jump List.449 List.474 List.475 List.476 List.477 List.478;
 
-procedure Num.123 (#Attr.2):
-    let Num.266 : U8 = lowlevel NumIntCast #Attr.2;
-    ret Num.266;
+procedure Num.125 (#Attr.2):
+    let Num.265 : U8 = lowlevel NumIntCast #Attr.2;
+    ret Num.265;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.269 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.269;
-
-procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.267 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.267;
-
-procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.270 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.270;
-
-procedure Num.24 (#Attr.2, #Attr.3):
-    let Num.268 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    let Num.268 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
     ret Num.268;
 
+procedure Num.20 (#Attr.2, #Attr.3):
+    let Num.266 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.266;
+
+procedure Num.22 (#Attr.2, #Attr.3):
+    let Num.269 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.269;
+
+procedure Num.24 (#Attr.2, #Attr.3):
+    let Num.267 : Int1 = lowlevel NumGt #Attr.2 #Attr.3;
+    ret Num.267;
+
 procedure Str.12 (#Attr.2):
-    let Str.266 : List U8 = lowlevel StrToUtf8 #Attr.2;
-    ret Str.266;
+    let Str.280 : List U8 = lowlevel StrToUtf8 #Attr.2;
+    ret Str.280;
 
 procedure Str.48 (#Attr.2, #Attr.3, #Attr.4):
-    let Str.260 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
-    ret Str.260;
+    let Str.274 : {U64, Str, Int1, U8} = lowlevel StrFromUtf8Range #Attr.2 #Attr.3 #Attr.4;
+    ret Str.274;
 
-procedure Str.9 (Str.73):
-    let Str.258 : U64 = 0i64;
-    let Str.259 : U64 = CallByName List.6 Str.73;
-    let Str.74 : {U64, Str, Int1, U8} = CallByName Str.48 Str.73 Str.258 Str.259;
-    let Str.255 : Int1 = StructAtIndex 2 Str.74;
-    if Str.255 then
-        let Str.257 : Str = StructAtIndex 1 Str.74;
-        inc Str.257;
-        dec Str.74;
-        let Str.256 : [C {U64, U8}, C Str] = TagId(1) Str.257;
-        ret Str.256;
+procedure Str.9 (Str.76):
+    let Str.272 : U64 = 0i64;
+    let Str.273 : U64 = CallByName List.6 Str.76;
+    let Str.77 : {U64, Str, Int1, U8} = CallByName Str.48 Str.76 Str.272 Str.273;
+    let Str.269 : Int1 = StructAtIndex 2 Str.77;
+    if Str.269 then
+        let Str.271 : Str = StructAtIndex 1 Str.77;
+        inc Str.271;
+        dec Str.77;
+        let Str.270 : [C {U64, U8}, C Str] = TagId(1) Str.271;
+        ret Str.270;
     else
-        let Str.253 : U8 = StructAtIndex 3 Str.74;
-        let Str.254 : U64 = StructAtIndex 0 Str.74;
-        dec Str.74;
-        let Str.252 : {U64, U8} = Struct {Str.254, Str.253};
-        let Str.251 : [C {U64, U8}, C Str] = TagId(0) Str.252;
-        ret Str.251;
+        let Str.267 : U8 = StructAtIndex 3 Str.77;
+        let Str.268 : U64 = StructAtIndex 0 Str.77;
+        dec Str.77;
+        let Str.266 : {U64, U8} = Struct {Str.268, Str.267};
+        let Str.265 : [C {U64, U8}, C Str] = TagId(0) Str.266;
+        ret Str.265;
 
 procedure Test.0 ():
     let Test.13 : Str = "foo";
diff --git a/crates/compiler/test_mono/generated/factorial.txt b/crates/compiler/test_mono/generated/factorial.txt
index 9aee646f72..b0319aa20a 100644
--- a/crates/compiler/test_mono/generated/factorial.txt
+++ b/crates/compiler/test_mono/generated/factorial.txt
@@ -1,10 +1,10 @@
 procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.258 : I64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : I64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Num.21 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.15, Test.16):
     joinpoint Test.7 Test.2 Test.3:
diff --git a/crates/compiler/test_mono/generated/guard_pattern_true.txt b/crates/compiler/test_mono/generated/guard_pattern_true.txt
index f535579130..dfded1801e 100644
--- a/crates/compiler/test_mono/generated/guard_pattern_true.txt
+++ b/crates/compiler/test_mono/generated/guard_pattern_true.txt
@@ -1,6 +1,6 @@
 procedure Bool.1 ():
-    let Bool.11 : Int1 = false;
-    ret Bool.11;
+    let Bool.23 : Int1 = false;
+    ret Bool.23;
 
 procedure Test.1 (Test.2):
     let Test.5 : I64 = 2i64;
diff --git a/crates/compiler/test_mono/generated/if_guard_bind_variable_false.txt b/crates/compiler/test_mono/generated/if_guard_bind_variable_false.txt
index 1565f25f88..b8a0dde808 100644
--- a/crates/compiler/test_mono/generated/if_guard_bind_variable_false.txt
+++ b/crates/compiler/test_mono/generated/if_guard_bind_variable_false.txt
@@ -1,6 +1,6 @@
-procedure Bool.7 (#Attr.2, #Attr.3):
-    let Bool.11 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
-    ret Bool.11;
+procedure Bool.11 (#Attr.2, #Attr.3):
+    let Bool.23 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
+    ret Bool.23;
 
 procedure Test.1 (Test.3):
     let Test.6 : I64 = 10i64;
@@ -13,7 +13,7 @@ procedure Test.1 (Test.3):
             ret Test.11;
     in
     let Test.10 : I64 = 5i64;
-    let Test.9 : Int1 = CallByName Bool.7 Test.6 Test.10;
+    let Test.9 : Int1 = CallByName Bool.11 Test.6 Test.10;
     jump Test.8 Test.9;
 
 procedure Test.0 ():
diff --git a/crates/compiler/test_mono/generated/if_multi_branch.txt b/crates/compiler/test_mono/generated/if_multi_branch.txt
index 36dddc2fe9..3b9a81546f 100644
--- a/crates/compiler/test_mono/generated/if_multi_branch.txt
+++ b/crates/compiler/test_mono/generated/if_multi_branch.txt
@@ -1,10 +1,10 @@
 procedure Bool.1 ():
-    let Bool.11 : Int1 = false;
-    ret Bool.11;
+    let Bool.23 : Int1 = false;
+    ret Bool.23;
 
 procedure Bool.2 ():
-    let Bool.12 : Int1 = true;
-    ret Bool.12;
+    let Bool.24 : Int1 = true;
+    ret Bool.24;
 
 procedure Test.0 ():
     let Test.4 : Int1 = CallByName Bool.2;
diff --git a/crates/compiler/test_mono/generated/ir_int_add.txt b/crates/compiler/test_mono/generated/ir_int_add.txt
index d8abd2d336..ca23069c99 100644
--- a/crates/compiler/test_mono/generated/ir_int_add.txt
+++ b/crates/compiler/test_mono/generated/ir_int_add.txt
@@ -1,10 +1,10 @@
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.259 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.259;
+    let Num.258 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.258;
 
 procedure Test.0 ():
     let Test.1 : List I64 = Array [1i64, 2i64];
diff --git a/crates/compiler/test_mono/generated/ir_plus.txt b/crates/compiler/test_mono/generated/ir_plus.txt
index 2bbd4d95d2..2994403a5a 100644
--- a/crates/compiler/test_mono/generated/ir_plus.txt
+++ b/crates/compiler/test_mono/generated/ir_plus.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.2 : I64 = 1i64;
diff --git a/crates/compiler/test_mono/generated/ir_round.txt b/crates/compiler/test_mono/generated/ir_round.txt
index 69029d87c2..0ba65b4515 100644
--- a/crates/compiler/test_mono/generated/ir_round.txt
+++ b/crates/compiler/test_mono/generated/ir_round.txt
@@ -1,6 +1,6 @@
 procedure Num.45 (#Attr.2):
-    let Num.257 : I64 = lowlevel NumRound #Attr.2;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumRound #Attr.2;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.2 : Float64 = 3.6f64;
diff --git a/crates/compiler/test_mono/generated/ir_two_defs.txt b/crates/compiler/test_mono/generated/ir_two_defs.txt
index f54ffd118b..aa2e631fbb 100644
--- a/crates/compiler/test_mono/generated/ir_two_defs.txt
+++ b/crates/compiler/test_mono/generated/ir_two_defs.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.1 : I64 = 3i64;
diff --git a/crates/compiler/test_mono/generated/ir_when_idiv.txt b/crates/compiler/test_mono/generated/ir_when_idiv.txt
index 6ab0065bc7..5bd2abf771 100644
--- a/crates/compiler/test_mono/generated/ir_when_idiv.txt
+++ b/crates/compiler/test_mono/generated/ir_when_idiv.txt
@@ -1,22 +1,22 @@
-procedure Bool.7 (#Attr.2, #Attr.3):
-    let Bool.11 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
-    ret Bool.11;
+procedure Num.30 (#Attr.2):
+    let Num.263 : I64 = 0i64;
+    let Num.262 : Int1 = lowlevel Eq #Attr.2 Num.263;
+    ret Num.262;
 
 procedure Num.39 (#Attr.2, #Attr.3):
-    let Num.259 : I64 = lowlevel NumDivTruncUnchecked #Attr.2 #Attr.3;
-    ret Num.259;
+    let Num.258 : I64 = lowlevel NumDivTruncUnchecked #Attr.2 #Attr.3;
+    ret Num.258;
 
-procedure Num.40 (Num.229, Num.230):
-    let Num.263 : I64 = 0i64;
-    let Num.260 : Int1 = CallByName Bool.7 Num.230 Num.263;
-    if Num.260 then
-        let Num.262 : {} = Struct {};
-        let Num.261 : [C {}, C I64] = TagId(0) Num.262;
-        ret Num.261;
+procedure Num.40 (Num.228, Num.229):
+    let Num.259 : Int1 = CallByName Num.30 Num.229;
+    if Num.259 then
+        let Num.261 : {} = Struct {};
+        let Num.260 : [C {}, C I64] = TagId(0) Num.261;
+        ret Num.260;
     else
-        let Num.258 : I64 = CallByName Num.39 Num.229 Num.230;
-        let Num.257 : [C {}, C I64] = TagId(1) Num.258;
-        ret Num.257;
+        let Num.257 : I64 = CallByName Num.39 Num.228 Num.229;
+        let Num.256 : [C {}, C I64] = TagId(1) Num.257;
+        ret Num.256;
 
 procedure Test.0 ():
     let Test.8 : I64 = 1000i64;
diff --git a/crates/compiler/test_mono/generated/ir_when_just.txt b/crates/compiler/test_mono/generated/ir_when_just.txt
index 8ceef4e3e4..95413986b7 100644
--- a/crates/compiler/test_mono/generated/ir_when_just.txt
+++ b/crates/compiler/test_mono/generated/ir_when_just.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.10 : I64 = 41i64;
diff --git a/crates/compiler/test_mono/generated/is_nil.txt b/crates/compiler/test_mono/generated/is_nil.txt
index aaea58f73a..e130f31ad5 100644
--- a/crates/compiler/test_mono/generated/is_nil.txt
+++ b/crates/compiler/test_mono/generated/is_nil.txt
@@ -1,10 +1,10 @@
 procedure Bool.1 ():
-    let Bool.12 : Int1 = false;
-    ret Bool.12;
+    let Bool.24 : Int1 = false;
+    ret Bool.24;
 
 procedure Bool.2 ():
-    let Bool.11 : Int1 = true;
-    ret Bool.11;
+    let Bool.23 : Int1 = true;
+    ret Bool.23;
 
 procedure Test.2 (Test.4):
     let Test.11 : U8 = 1i64;
diff --git a/crates/compiler/test_mono/generated/issue_2583_specialize_errors_behind_unified_branches.txt b/crates/compiler/test_mono/generated/issue_2583_specialize_errors_behind_unified_branches.txt
index 4dcb37efbc..132b5e6fa0 100644
--- a/crates/compiler/test_mono/generated/issue_2583_specialize_errors_behind_unified_branches.txt
+++ b/crates/compiler/test_mono/generated/issue_2583_specialize_errors_behind_unified_branches.txt
@@ -1,71 +1,71 @@
+procedure Bool.11 (#Attr.2, #Attr.3):
+    let Bool.24 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
+    ret Bool.24;
+
 procedure Bool.2 ():
-    let Bool.11 : Int1 = true;
-    ret Bool.11;
+    let Bool.23 : Int1 = true;
+    ret Bool.23;
 
-procedure Bool.7 (#Attr.2, #Attr.3):
-    let Bool.12 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
-    ret Bool.12;
-
-procedure List.2 (List.90, List.91):
-    let List.394 : U64 = CallByName List.6 List.90;
-    let List.390 : Int1 = CallByName Num.22 List.91 List.394;
-    if List.390 then
-        let List.392 : I64 = CallByName List.66 List.90 List.91;
-        let List.391 : [C {}, C I64] = TagId(1) List.392;
-        ret List.391;
+procedure List.2 (List.94, List.95):
+    let List.423 : U64 = CallByName List.6 List.94;
+    let List.419 : Int1 = CallByName Num.22 List.95 List.423;
+    if List.419 then
+        let List.421 : I64 = CallByName List.66 List.94 List.95;
+        let List.420 : [C {}, C I64] = TagId(1) List.421;
+        ret List.420;
     else
-        let List.389 : {} = Struct {};
-        let List.388 : [C {}, C I64] = TagId(0) List.389;
-        ret List.388;
+        let List.418 : {} = Struct {};
+        let List.417 : [C {}, C I64] = TagId(0) List.418;
+        ret List.417;
 
 procedure List.6 (#Attr.2):
-    let List.395 : U64 = lowlevel ListLen #Attr.2;
-    ret List.395;
+    let List.424 : U64 = lowlevel ListLen #Attr.2;
+    ret List.424;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.393 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.393;
+    let List.422 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.422;
 
-procedure List.9 (List.213):
-    let List.387 : U64 = 0i64;
-    let List.380 : [C {}, C I64] = CallByName List.2 List.213 List.387;
-    let List.384 : U8 = 1i64;
-    let List.385 : U8 = GetTagId List.380;
-    let List.386 : Int1 = lowlevel Eq List.384 List.385;
-    if List.386 then
-        let List.214 : I64 = UnionAtIndex (Id 1) (Index 0) List.380;
-        let List.381 : [C Int1, C I64] = TagId(1) List.214;
-        ret List.381;
+procedure List.9 (List.242):
+    let List.416 : U64 = 0i64;
+    let List.409 : [C {}, C I64] = CallByName List.2 List.242 List.416;
+    let List.413 : U8 = 1i64;
+    let List.414 : U8 = GetTagId List.409;
+    let List.415 : Int1 = lowlevel Eq List.413 List.414;
+    if List.415 then
+        let List.243 : I64 = UnionAtIndex (Id 1) (Index 0) List.409;
+        let List.410 : [C Int1, C I64] = TagId(1) List.243;
+        ret List.410;
     else
-        let List.383 : Int1 = true;
-        let List.382 : [C Int1, C I64] = TagId(0) List.383;
-        ret List.382;
+        let List.412 : Int1 = true;
+        let List.411 : [C Int1, C I64] = TagId(0) List.412;
+        ret List.411;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.256;
 
-procedure Str.27 (Str.93):
-    let Str.251 : [C Int1, C I64] = CallByName Str.66 Str.93;
-    ret Str.251;
+procedure Str.27 (Str.96):
+    let Str.265 : [C Int1, C I64] = CallByName Str.69 Str.96;
+    ret Str.265;
 
 procedure Str.47 (#Attr.2):
-    let Str.259 : {I64, U8} = lowlevel StrToNum #Attr.2;
-    ret Str.259;
+    let Str.273 : {I64, U8} = lowlevel StrToNum #Attr.2;
+    ret Str.273;
 
-procedure Str.66 (Str.222):
-    let Str.223 : {I64, U8} = CallByName Str.47 Str.222;
-    let Str.257 : U8 = StructAtIndex 1 Str.223;
-    let Str.258 : U8 = 0i64;
-    let Str.254 : Int1 = CallByName Bool.7 Str.257 Str.258;
-    if Str.254 then
-        let Str.256 : I64 = StructAtIndex 0 Str.223;
-        let Str.255 : [C Int1, C I64] = TagId(1) Str.256;
-        ret Str.255;
+procedure Str.69 (Str.231):
+    let Str.232 : {I64, U8} = CallByName Str.47 Str.231;
+    let Str.271 : U8 = StructAtIndex 1 Str.232;
+    let Str.272 : U8 = 0i64;
+    let Str.268 : Int1 = CallByName Bool.11 Str.271 Str.272;
+    if Str.268 then
+        let Str.270 : I64 = StructAtIndex 0 Str.232;
+        let Str.269 : [C Int1, C I64] = TagId(1) Str.270;
+        ret Str.269;
     else
-        let Str.253 : Int1 = false;
-        let Str.252 : [C Int1, C I64] = TagId(0) Str.253;
-        ret Str.252;
+        let Str.267 : Int1 = false;
+        let Str.266 : [C Int1, C I64] = TagId(0) Str.267;
+        ret Str.266;
 
 procedure Test.0 ():
     let Test.3 : Int1 = CallByName Bool.2;
diff --git a/crates/compiler/test_mono/generated/issue_3669.txt b/crates/compiler/test_mono/generated/issue_3669.txt
index 11d9485149..3f50a60607 100644
--- a/crates/compiler/test_mono/generated/issue_3669.txt
+++ b/crates/compiler/test_mono/generated/issue_3669.txt
@@ -1,6 +1,6 @@
-procedure Bool.7 (#Attr.2, #Attr.3):
-    let Bool.11 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
-    ret Bool.11;
+procedure Bool.11 (#Attr.2, #Attr.3):
+    let Bool.23 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
+    ret Bool.23;
 
 procedure Test.2 (Test.19):
     joinpoint Test.13 Test.7:
@@ -21,6 +21,6 @@ procedure Test.0 ():
     let Test.10 : {} = CallByName Test.2 Test.12;
     dec Test.12;
     let Test.11 : {} = Struct {};
-    let Test.8 : Int1 = CallByName Bool.7 Test.10 Test.11;
+    let Test.8 : Int1 = CallByName Bool.11 Test.10 Test.11;
     let Test.9 : Str = "";
     ret Test.9;
diff --git a/crates/compiler/test_mono/generated/lambda_capture_niche_u8_vs_u64.txt b/crates/compiler/test_mono/generated/lambda_capture_niche_u8_vs_u64.txt
index b9c8c3a9f4..351d5255f1 100644
--- a/crates/compiler/test_mono/generated/lambda_capture_niche_u8_vs_u64.txt
+++ b/crates/compiler/test_mono/generated/lambda_capture_niche_u8_vs_u64.txt
@@ -1,11 +1,11 @@
+procedure Num.94 (#Attr.2):
+    let Num.256 : Str = lowlevel NumToStr #Attr.2;
+    ret Num.256;
+
 procedure Num.94 (#Attr.2):
     let Num.257 : Str = lowlevel NumToStr #Attr.2;
     ret Num.257;
 
-procedure Num.94 (#Attr.2):
-    let Num.258 : Str = lowlevel NumToStr #Attr.2;
-    ret Num.258;
-
 procedure Test.1 (Test.4):
     let Test.16 : [C U8, C U64] = TagId(1) Test.4;
     ret Test.16;
diff --git a/crates/compiler/test_mono/generated/list_append.txt b/crates/compiler/test_mono/generated/list_append.txt
index 4ec9e800f3..224cea70dd 100644
--- a/crates/compiler/test_mono/generated/list_append.txt
+++ b/crates/compiler/test_mono/generated/list_append.txt
@@ -1,16 +1,16 @@
-procedure List.4 (List.101, List.102):
-    let List.383 : U64 = 1i64;
-    let List.381 : List I64 = CallByName List.70 List.101 List.383;
-    let List.380 : List I64 = CallByName List.71 List.381 List.102;
-    ret List.380;
+procedure List.4 (List.105, List.106):
+    let List.412 : U64 = 1i64;
+    let List.410 : List I64 = CallByName List.70 List.105 List.412;
+    let List.409 : List I64 = CallByName List.71 List.410 List.106;
+    ret List.409;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.384 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.384;
+    let List.413 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.382 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.382;
+    let List.411 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.411;
 
 procedure Test.0 ():
     let Test.2 : List I64 = Array [1i64];
diff --git a/crates/compiler/test_mono/generated/list_append_closure.txt b/crates/compiler/test_mono/generated/list_append_closure.txt
index 66396fabc0..2f02f8b4e4 100644
--- a/crates/compiler/test_mono/generated/list_append_closure.txt
+++ b/crates/compiler/test_mono/generated/list_append_closure.txt
@@ -1,16 +1,16 @@
-procedure List.4 (List.101, List.102):
-    let List.383 : U64 = 1i64;
-    let List.381 : List I64 = CallByName List.70 List.101 List.383;
-    let List.380 : List I64 = CallByName List.71 List.381 List.102;
-    ret List.380;
+procedure List.4 (List.105, List.106):
+    let List.412 : U64 = 1i64;
+    let List.410 : List I64 = CallByName List.70 List.105 List.412;
+    let List.409 : List I64 = CallByName List.71 List.410 List.106;
+    ret List.409;
 
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.384 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.384;
+    let List.413 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.413;
 
 procedure List.71 (#Attr.2, #Attr.3):
-    let List.382 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.382;
+    let List.411 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.411;
 
 procedure Test.1 (Test.2):
     let Test.6 : I64 = 42i64;
diff --git a/crates/compiler/test_mono/generated/list_cannot_update_inplace.txt b/crates/compiler/test_mono/generated/list_cannot_update_inplace.txt
index d8f76d3ba2..638d364d74 100644
--- a/crates/compiler/test_mono/generated/list_cannot_update_inplace.txt
+++ b/crates/compiler/test_mono/generated/list_cannot_update_inplace.txt
@@ -1,35 +1,35 @@
-procedure List.3 (List.98, List.99, List.100):
-    let List.383 : {List I64, I64} = CallByName List.64 List.98 List.99 List.100;
-    let List.382 : List I64 = StructAtIndex 0 List.383;
-    inc List.382;
-    dec List.383;
-    ret List.382;
+procedure List.3 (List.102, List.103, List.104):
+    let List.412 : {List I64, I64} = CallByName List.64 List.102 List.103 List.104;
+    let List.411 : List I64 = StructAtIndex 0 List.412;
+    inc List.411;
+    dec List.412;
+    ret List.411;
 
 procedure List.6 (#Attr.2):
-    let List.381 : U64 = lowlevel ListLen #Attr.2;
-    ret List.381;
+    let List.410 : U64 = lowlevel ListLen #Attr.2;
+    ret List.410;
 
-procedure List.64 (List.95, List.96, List.97):
-    let List.388 : U64 = CallByName List.6 List.95;
-    let List.385 : Int1 = CallByName Num.22 List.96 List.388;
-    if List.385 then
-        let List.386 : {List I64, I64} = CallByName List.67 List.95 List.96 List.97;
-        ret List.386;
+procedure List.64 (List.99, List.100, List.101):
+    let List.417 : U64 = CallByName List.6 List.99;
+    let List.414 : Int1 = CallByName Num.22 List.100 List.417;
+    if List.414 then
+        let List.415 : {List I64, I64} = CallByName List.67 List.99 List.100 List.101;
+        ret List.415;
     else
-        let List.384 : {List I64, I64} = Struct {List.95, List.97};
-        ret List.384;
+        let List.413 : {List I64, I64} = Struct {List.99, List.101};
+        ret List.413;
 
 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.387 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.387;
+    let List.416 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.416;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.258 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Test.1 ():
     let Test.8 : List I64 = Array [1i64, 2i64, 3i64];
diff --git a/crates/compiler/test_mono/generated/list_get.txt b/crates/compiler/test_mono/generated/list_get.txt
index db3e811cb3..53734e6aa0 100644
--- a/crates/compiler/test_mono/generated/list_get.txt
+++ b/crates/compiler/test_mono/generated/list_get.txt
@@ -1,26 +1,26 @@
-procedure List.2 (List.90, List.91):
-    let List.386 : U64 = CallByName List.6 List.90;
-    let List.382 : Int1 = CallByName Num.22 List.91 List.386;
-    if List.382 then
-        let List.384 : I64 = CallByName List.66 List.90 List.91;
-        let List.383 : [C {}, C I64] = TagId(1) List.384;
-        ret List.383;
+procedure List.2 (List.94, List.95):
+    let List.415 : U64 = CallByName List.6 List.94;
+    let List.411 : Int1 = CallByName Num.22 List.95 List.415;
+    if List.411 then
+        let List.413 : I64 = CallByName List.66 List.94 List.95;
+        let List.412 : [C {}, C I64] = TagId(1) List.413;
+        ret List.412;
     else
-        let List.381 : {} = Struct {};
-        let List.380 : [C {}, C I64] = TagId(0) List.381;
-        ret List.380;
+        let List.410 : {} = Struct {};
+        let List.409 : [C {}, C I64] = TagId(0) List.410;
+        ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.385 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.385;
+    let List.414 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.2):
     let Test.6 : List I64 = Array [1i64, 2i64, 3i64];
diff --git a/crates/compiler/test_mono/generated/list_len.txt b/crates/compiler/test_mono/generated/list_len.txt
index 75148df945..ba25fbc1f1 100644
--- a/crates/compiler/test_mono/generated/list_len.txt
+++ b/crates/compiler/test_mono/generated/list_len.txt
@@ -1,14 +1,14 @@
 procedure List.6 (#Attr.2):
-    let List.380 : U64 = lowlevel ListLen #Attr.2;
-    ret List.380;
+    let List.409 : U64 = lowlevel ListLen #Attr.2;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.381 : U64 = lowlevel ListLen #Attr.2;
-    ret List.381;
+    let List.410 : U64 = lowlevel ListLen #Attr.2;
+    ret List.410;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.1 : List I64 = Array [1i64, 2i64, 3i64];
diff --git a/crates/compiler/test_mono/generated/list_map_closure_borrows.txt b/crates/compiler/test_mono/generated/list_map_closure_borrows.txt
index 102f75b8cb..ca1cabd824 100644
--- a/crates/compiler/test_mono/generated/list_map_closure_borrows.txt
+++ b/crates/compiler/test_mono/generated/list_map_closure_borrows.txt
@@ -1,38 +1,38 @@
-procedure List.2 (List.90, List.91):
-    let List.386 : U64 = CallByName List.6 List.90;
-    let List.382 : Int1 = CallByName Num.22 List.91 List.386;
-    if List.382 then
-        let List.384 : Str = CallByName List.66 List.90 List.91;
-        let List.383 : [C {}, C Str] = TagId(1) List.384;
-        ret List.383;
+procedure List.2 (List.94, List.95):
+    let List.415 : U64 = CallByName List.6 List.94;
+    let List.411 : Int1 = CallByName Num.22 List.95 List.415;
+    if List.411 then
+        let List.413 : Str = CallByName List.66 List.94 List.95;
+        let List.412 : [C {}, C Str] = TagId(1) List.413;
+        ret List.412;
     else
-        let List.381 : {} = Struct {};
-        let List.380 : [C {}, C Str] = TagId(0) List.381;
-        ret List.380;
+        let List.410 : {} = Struct {};
+        let List.409 : [C {}, C Str] = TagId(0) List.410;
+        ret List.409;
 
 procedure List.5 (#Attr.2, #Attr.3):
-    let List.388 : List Str = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.3 #Attr.3;
-    ret List.388;
+    let List.417 : List Str = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.3 #Attr.3;
+    ret List.417;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.385 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.385;
+    let List.414 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Str.16 (#Attr.2, #Attr.3):
-    let Str.251 : Str = lowlevel StrRepeat #Attr.2 #Attr.3;
-    ret Str.251;
+    let Str.265 : Str = lowlevel StrRepeat #Attr.2 #Attr.3;
+    ret Str.265;
 
 procedure Str.3 (#Attr.2, #Attr.3):
-    let Str.252 : Str = lowlevel StrConcat #Attr.2 #Attr.3;
-    ret Str.252;
+    let Str.266 : Str = lowlevel StrConcat #Attr.2 #Attr.3;
+    ret Str.266;
 
 procedure Test.1 ():
     let Test.21 : Str = "lllllllllllllllllllllooooooooooong";
diff --git a/crates/compiler/test_mono/generated/list_map_closure_owns.txt b/crates/compiler/test_mono/generated/list_map_closure_owns.txt
index 85c4902acb..dd79d46b04 100644
--- a/crates/compiler/test_mono/generated/list_map_closure_owns.txt
+++ b/crates/compiler/test_mono/generated/list_map_closure_owns.txt
@@ -1,36 +1,35 @@
-procedure List.2 (List.90, List.91):
-    let List.386 : U64 = CallByName List.6 List.90;
-    let List.382 : Int1 = CallByName Num.22 List.91 List.386;
-    if List.382 then
-        let List.384 : Str = CallByName List.66 List.90 List.91;
-        let List.383 : [C {}, C Str] = TagId(1) List.384;
-        ret List.383;
+procedure List.2 (List.94, List.95):
+    let List.415 : U64 = CallByName List.6 List.94;
+    let List.411 : Int1 = CallByName Num.22 List.95 List.415;
+    if List.411 then
+        let List.413 : Str = CallByName List.66 List.94 List.95;
+        let List.412 : [C {}, C Str] = TagId(1) List.413;
+        ret List.412;
     else
-        let List.381 : {} = Struct {};
-        let List.380 : [C {}, C Str] = TagId(0) List.381;
-        ret List.380;
+        let List.410 : {} = Struct {};
+        let List.409 : [C {}, C Str] = TagId(0) List.410;
+        ret List.409;
 
 procedure List.5 (#Attr.2, #Attr.3):
-    inc #Attr.2;
-    let List.388 : List Str = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.3 #Attr.3;
+    let List.417 : List Str = lowlevel ListMap { xs: `#Attr.#arg1` } #Attr.2 Test.3 #Attr.3;
     decref #Attr.2;
-    ret List.388;
+    ret List.417;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.385 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.385;
+    let List.414 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Str.3 (#Attr.2, #Attr.3):
-    let Str.252 : Str = lowlevel StrConcat #Attr.2 #Attr.3;
-    ret Str.252;
+    let Str.266 : Str = lowlevel StrConcat #Attr.2 #Attr.3;
+    ret Str.266;
 
 procedure Test.1 ():
     let Test.21 : Str = "lllllllllllllllllllllooooooooooong";
@@ -44,7 +43,6 @@ procedure Test.2 ():
     let Test.15 : List Str = CallByName Test.1;
     let Test.16 : {} = Struct {};
     let Test.14 : List Str = CallByName List.5 Test.15 Test.16;
-    dec Test.15;
     ret Test.14;
 
 procedure Test.3 (Test.4):
diff --git a/crates/compiler/test_mono/generated/list_pass_to_function.txt b/crates/compiler/test_mono/generated/list_pass_to_function.txt
index 97947c1243..4bdc8393cf 100644
--- a/crates/compiler/test_mono/generated/list_pass_to_function.txt
+++ b/crates/compiler/test_mono/generated/list_pass_to_function.txt
@@ -1,31 +1,31 @@
-procedure List.3 (List.98, List.99, List.100):
-    let List.381 : {List I64, I64} = CallByName List.64 List.98 List.99 List.100;
-    let List.380 : List I64 = StructAtIndex 0 List.381;
-    inc List.380;
-    dec List.381;
-    ret List.380;
+procedure List.3 (List.102, List.103, List.104):
+    let List.410 : {List I64, I64} = CallByName List.64 List.102 List.103 List.104;
+    let List.409 : List I64 = StructAtIndex 0 List.410;
+    inc List.409;
+    dec List.410;
+    ret List.409;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
-procedure List.64 (List.95, List.96, List.97):
-    let List.386 : U64 = CallByName List.6 List.95;
-    let List.383 : Int1 = CallByName Num.22 List.96 List.386;
-    if List.383 then
-        let List.384 : {List I64, I64} = CallByName List.67 List.95 List.96 List.97;
-        ret List.384;
+procedure List.64 (List.99, List.100, List.101):
+    let List.415 : U64 = CallByName List.6 List.99;
+    let List.412 : Int1 = CallByName Num.22 List.100 List.415;
+    if List.412 then
+        let List.413 : {List I64, I64} = CallByName List.67 List.99 List.100 List.101;
+        ret List.413;
     else
-        let List.382 : {List I64, I64} = Struct {List.95, List.97};
-        ret List.382;
+        let List.411 : {List I64, I64} = Struct {List.99, List.101};
+        ret List.411;
 
 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.385 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.385;
+    let List.414 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.257 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.2 (Test.3):
     let Test.6 : U64 = 0i64;
diff --git a/crates/compiler/test_mono/generated/list_sort_asc.txt b/crates/compiler/test_mono/generated/list_sort_asc.txt
index e3bee9c60c..a375c93ae5 100644
--- a/crates/compiler/test_mono/generated/list_sort_asc.txt
+++ b/crates/compiler/test_mono/generated/list_sort_asc.txt
@@ -1,20 +1,20 @@
 procedure List.28 (#Attr.2, #Attr.3):
-    let List.382 : List I64 = lowlevel ListSortWith { xs: `#Attr.#arg1` } #Attr.2 Num.46 #Attr.3;
+    let List.411 : List I64 = lowlevel ListSortWith { xs: `#Attr.#arg1` } #Attr.2 Num.46 #Attr.3;
     let #Derived_gen.0 : Int1 = lowlevel ListIsUnique #Attr.2;
     if #Derived_gen.0 then
-        ret List.382;
+        ret List.411;
     else
         decref #Attr.2;
-        ret List.382;
+        ret List.411;
 
-procedure List.59 (List.208):
-    let List.381 : {} = Struct {};
-    let List.380 : List I64 = CallByName List.28 List.208 List.381;
-    ret List.380;
+procedure List.59 (List.237):
+    let List.410 : {} = Struct {};
+    let List.409 : List I64 = CallByName List.28 List.237 List.410;
+    ret List.409;
 
 procedure Num.46 (#Attr.2, #Attr.3):
-    let Num.257 : U8 = lowlevel NumCompare #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : U8 = lowlevel NumCompare #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.2 : List I64 = Array [4i64, 3i64, 2i64, 1i64];
diff --git a/crates/compiler/test_mono/generated/monomorphized_tag_with_aliased_args.txt b/crates/compiler/test_mono/generated/monomorphized_tag_with_aliased_args.txt
index fe89b5144c..490a3c5643 100644
--- a/crates/compiler/test_mono/generated/monomorphized_tag_with_aliased_args.txt
+++ b/crates/compiler/test_mono/generated/monomorphized_tag_with_aliased_args.txt
@@ -1,6 +1,6 @@
 procedure Bool.1 ():
-    let Bool.12 : Int1 = false;
-    ret Bool.12;
+    let Bool.24 : Int1 = false;
+    ret Bool.24;
 
 procedure Test.4 (Test.6):
     let Test.8 : U64 = 1i64;
diff --git a/crates/compiler/test_mono/generated/nested_pattern_match.txt b/crates/compiler/test_mono/generated/nested_pattern_match.txt
index e8e714e59e..4b2af8c406 100644
--- a/crates/compiler/test_mono/generated/nested_pattern_match.txt
+++ b/crates/compiler/test_mono/generated/nested_pattern_match.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.19 : I64 = 41i64;
diff --git a/crates/compiler/test_mono/generated/num_width_gt_u8_layout_as_float.txt b/crates/compiler/test_mono/generated/num_width_gt_u8_layout_as_float.txt
index 1925eaca63..e5c7df8fe3 100644
--- a/crates/compiler/test_mono/generated/num_width_gt_u8_layout_as_float.txt
+++ b/crates/compiler/test_mono/generated/num_width_gt_u8_layout_as_float.txt
@@ -1,6 +1,6 @@
 procedure Num.37 (#Attr.2, #Attr.3):
-    let Num.257 : Float64 = lowlevel NumDivFrac #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : Float64 = lowlevel NumDivFrac #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.2 : Float64 = 1f64;
diff --git a/crates/compiler/test_mono/generated/optional_when.txt b/crates/compiler/test_mono/generated/optional_when.txt
index 1da4dd989c..28667ba1d6 100644
--- a/crates/compiler/test_mono/generated/optional_when.txt
+++ b/crates/compiler/test_mono/generated/optional_when.txt
@@ -1,6 +1,6 @@
 procedure Num.21 (#Attr.2, #Attr.3):
-    let Num.259 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
-    ret Num.259;
+    let Num.258 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
+    ret Num.258;
 
 procedure Test.1 (Test.6):
     let Test.21 : Int1 = false;
diff --git a/crates/compiler/test_mono/generated/quicksort_help.txt b/crates/compiler/test_mono/generated/quicksort_help.txt
index 884a9adbad..b8a6ea2e5d 100644
--- a/crates/compiler/test_mono/generated/quicksort_help.txt
+++ b/crates/compiler/test_mono/generated/quicksort_help.txt
@@ -1,14 +1,14 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.258 : I64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : I64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.259 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.259;
+    let Num.258 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.258;
 
 procedure Test.1 (Test.24, Test.25, Test.26):
     joinpoint Test.12 Test.2 Test.3 Test.4:
diff --git a/crates/compiler/test_mono/generated/quicksort_swap.txt b/crates/compiler/test_mono/generated/quicksort_swap.txt
index ee01276f67..7714860bc7 100644
--- a/crates/compiler/test_mono/generated/quicksort_swap.txt
+++ b/crates/compiler/test_mono/generated/quicksort_swap.txt
@@ -1,47 +1,47 @@
-procedure List.2 (List.90, List.91):
-    let List.402 : U64 = CallByName List.6 List.90;
-    let List.399 : Int1 = CallByName Num.22 List.91 List.402;
-    if List.399 then
-        let List.401 : I64 = CallByName List.66 List.90 List.91;
-        let List.400 : [C {}, C I64] = TagId(1) List.401;
-        ret List.400;
+procedure List.2 (List.94, List.95):
+    let List.431 : U64 = CallByName List.6 List.94;
+    let List.428 : Int1 = CallByName Num.22 List.95 List.431;
+    if List.428 then
+        let List.430 : I64 = CallByName List.66 List.94 List.95;
+        let List.429 : [C {}, C I64] = TagId(1) List.430;
+        ret List.429;
     else
-        let List.398 : {} = Struct {};
-        let List.397 : [C {}, C I64] = TagId(0) List.398;
-        ret List.397;
+        let List.427 : {} = Struct {};
+        let List.426 : [C {}, C I64] = TagId(0) List.427;
+        ret List.426;
 
-procedure List.3 (List.98, List.99, List.100):
-    let List.389 : {List I64, I64} = CallByName List.64 List.98 List.99 List.100;
-    let List.388 : List I64 = StructAtIndex 0 List.389;
-    inc List.388;
-    dec List.389;
-    ret List.388;
+procedure List.3 (List.102, List.103, List.104):
+    let List.418 : {List I64, I64} = CallByName List.64 List.102 List.103 List.104;
+    let List.417 : List I64 = StructAtIndex 0 List.418;
+    inc List.417;
+    dec List.418;
+    ret List.417;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
-procedure List.64 (List.95, List.96, List.97):
-    let List.386 : U64 = CallByName List.6 List.95;
-    let List.383 : Int1 = CallByName Num.22 List.96 List.386;
-    if List.383 then
-        let List.384 : {List I64, I64} = CallByName List.67 List.95 List.96 List.97;
-        ret List.384;
+procedure List.64 (List.99, List.100, List.101):
+    let List.415 : U64 = CallByName List.6 List.99;
+    let List.412 : Int1 = CallByName Num.22 List.100 List.415;
+    if List.412 then
+        let List.413 : {List I64, I64} = CallByName List.67 List.99 List.100 List.101;
+        ret List.413;
     else
-        let List.382 : {List I64, I64} = Struct {List.95, List.97};
-        ret List.382;
+        let List.411 : {List I64, I64} = Struct {List.99, List.101};
+        ret List.411;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.395 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.395;
+    let List.424 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.424;
 
 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.385 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.385;
+    let List.414 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.259 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.259;
+    let Num.258 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.258;
 
 procedure Test.1 (Test.2):
     let Test.28 : U64 = 0i64;
diff --git a/crates/compiler/test_mono/generated/record_optional_field_function_no_use_default.txt b/crates/compiler/test_mono/generated/record_optional_field_function_no_use_default.txt
index 988b0cf432..2f7c2c8b22 100644
--- a/crates/compiler/test_mono/generated/record_optional_field_function_no_use_default.txt
+++ b/crates/compiler/test_mono/generated/record_optional_field_function_no_use_default.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.4):
     let Test.2 : I64 = StructAtIndex 0 Test.4;
diff --git a/crates/compiler/test_mono/generated/record_optional_field_function_use_default.txt b/crates/compiler/test_mono/generated/record_optional_field_function_use_default.txt
index 356f58f136..49267ae4b1 100644
--- a/crates/compiler/test_mono/generated/record_optional_field_function_use_default.txt
+++ b/crates/compiler/test_mono/generated/record_optional_field_function_use_default.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.4):
     let Test.2 : I64 = 10i64;
diff --git a/crates/compiler/test_mono/generated/record_optional_field_let_no_use_default.txt b/crates/compiler/test_mono/generated/record_optional_field_let_no_use_default.txt
index 2abaf868ba..21ebd109c8 100644
--- a/crates/compiler/test_mono/generated/record_optional_field_let_no_use_default.txt
+++ b/crates/compiler/test_mono/generated/record_optional_field_let_no_use_default.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.2):
     let Test.3 : I64 = StructAtIndex 0 Test.2;
diff --git a/crates/compiler/test_mono/generated/record_optional_field_let_use_default.txt b/crates/compiler/test_mono/generated/record_optional_field_let_use_default.txt
index b70eba153b..c960fd1fb2 100644
--- a/crates/compiler/test_mono/generated/record_optional_field_let_use_default.txt
+++ b/crates/compiler/test_mono/generated/record_optional_field_let_use_default.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.2):
     let Test.3 : I64 = 10i64;
diff --git a/crates/compiler/test_mono/generated/recursive_call_capturing_function.txt b/crates/compiler/test_mono/generated/recursive_call_capturing_function.txt
index 1d0e02c71f..b969b12528 100644
--- a/crates/compiler/test_mono/generated/recursive_call_capturing_function.txt
+++ b/crates/compiler/test_mono/generated/recursive_call_capturing_function.txt
@@ -1,10 +1,10 @@
 procedure Bool.2 ():
-    let Bool.11 : Int1 = true;
-    ret Bool.11;
+    let Bool.23 : Int1 = true;
+    ret Bool.23;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : U32 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : U32 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.2):
     let Test.8 : U32 = 0i64;
diff --git a/crates/compiler/test_mono/generated/rigids.txt b/crates/compiler/test_mono/generated/rigids.txt
index 3026b305c0..71b3ba4340 100644
--- a/crates/compiler/test_mono/generated/rigids.txt
+++ b/crates/compiler/test_mono/generated/rigids.txt
@@ -1,47 +1,47 @@
-procedure List.2 (List.90, List.91):
-    let List.402 : U64 = CallByName List.6 List.90;
-    let List.399 : Int1 = CallByName Num.22 List.91 List.402;
-    if List.399 then
-        let List.401 : I64 = CallByName List.66 List.90 List.91;
-        let List.400 : [C {}, C I64] = TagId(1) List.401;
-        ret List.400;
+procedure List.2 (List.94, List.95):
+    let List.431 : U64 = CallByName List.6 List.94;
+    let List.428 : Int1 = CallByName Num.22 List.95 List.431;
+    if List.428 then
+        let List.430 : I64 = CallByName List.66 List.94 List.95;
+        let List.429 : [C {}, C I64] = TagId(1) List.430;
+        ret List.429;
     else
-        let List.398 : {} = Struct {};
-        let List.397 : [C {}, C I64] = TagId(0) List.398;
-        ret List.397;
+        let List.427 : {} = Struct {};
+        let List.426 : [C {}, C I64] = TagId(0) List.427;
+        ret List.426;
 
-procedure List.3 (List.98, List.99, List.100):
-    let List.389 : {List I64, I64} = CallByName List.64 List.98 List.99 List.100;
-    let List.388 : List I64 = StructAtIndex 0 List.389;
-    inc List.388;
-    dec List.389;
-    ret List.388;
+procedure List.3 (List.102, List.103, List.104):
+    let List.418 : {List I64, I64} = CallByName List.64 List.102 List.103 List.104;
+    let List.417 : List I64 = StructAtIndex 0 List.418;
+    inc List.417;
+    dec List.418;
+    ret List.417;
 
 procedure List.6 (#Attr.2):
-    let List.387 : U64 = lowlevel ListLen #Attr.2;
-    ret List.387;
+    let List.416 : U64 = lowlevel ListLen #Attr.2;
+    ret List.416;
 
-procedure List.64 (List.95, List.96, List.97):
-    let List.386 : U64 = CallByName List.6 List.95;
-    let List.383 : Int1 = CallByName Num.22 List.96 List.386;
-    if List.383 then
-        let List.384 : {List I64, I64} = CallByName List.67 List.95 List.96 List.97;
-        ret List.384;
+procedure List.64 (List.99, List.100, List.101):
+    let List.415 : U64 = CallByName List.6 List.99;
+    let List.412 : Int1 = CallByName Num.22 List.100 List.415;
+    if List.412 then
+        let List.413 : {List I64, I64} = CallByName List.67 List.99 List.100 List.101;
+        ret List.413;
     else
-        let List.382 : {List I64, I64} = Struct {List.95, List.97};
-        ret List.382;
+        let List.411 : {List I64, I64} = Struct {List.99, List.101};
+        ret List.411;
 
 procedure List.66 (#Attr.2, #Attr.3):
-    let List.395 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.395;
+    let List.424 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.424;
 
 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.385 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.385;
+    let List.414 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.414;
 
 procedure Num.22 (#Attr.2, #Attr.3):
-    let Num.259 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
-    ret Num.259;
+    let Num.258 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
+    ret Num.258;
 
 procedure Test.1 (Test.2, Test.3, Test.4):
     let Test.29 : [C {}, C I64] = CallByName List.2 Test.4 Test.3;
diff --git a/crates/compiler/test_mono/generated/simple_if.txt b/crates/compiler/test_mono/generated/simple_if.txt
index 0ffc888c09..42fbbf320f 100644
--- a/crates/compiler/test_mono/generated/simple_if.txt
+++ b/crates/compiler/test_mono/generated/simple_if.txt
@@ -1,6 +1,6 @@
 procedure Bool.2 ():
-    let Bool.11 : Int1 = true;
-    ret Bool.11;
+    let Bool.23 : Int1 = true;
+    ret Bool.23;
 
 procedure Test.0 ():
     let Test.2 : Int1 = CallByName Bool.2;
diff --git a/crates/compiler/test_mono/generated/specialize_closures.txt b/crates/compiler/test_mono/generated/specialize_closures.txt
index 4dacbd022f..844180ae10 100644
--- a/crates/compiler/test_mono/generated/specialize_closures.txt
+++ b/crates/compiler/test_mono/generated/specialize_closures.txt
@@ -1,14 +1,14 @@
 procedure Bool.2 ():
-    let Bool.12 : Int1 = true;
-    ret Bool.12;
+    let Bool.24 : Int1 = true;
+    ret Bool.24;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.258 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Num.21 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.1 (Test.2, Test.3):
     let Test.15 : U8 = GetTagId Test.2;
diff --git a/crates/compiler/test_mono/generated/specialize_lowlevel.txt b/crates/compiler/test_mono/generated/specialize_lowlevel.txt
index 017db92ce7..cb54585dd7 100644
--- a/crates/compiler/test_mono/generated/specialize_lowlevel.txt
+++ b/crates/compiler/test_mono/generated/specialize_lowlevel.txt
@@ -1,14 +1,14 @@
 procedure Bool.2 ():
-    let Bool.11 : Int1 = true;
-    ret Bool.11;
+    let Bool.23 : Int1 = true;
+    ret Bool.23;
 
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.258 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Num.21 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumMul #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.6 (Test.8, #Attr.12):
     let Test.4 : I64 = UnionAtIndex (Id 0) (Index 0) #Attr.12;
diff --git a/crates/compiler/test_mono/generated/tail_call_elimination.txt b/crates/compiler/test_mono/generated/tail_call_elimination.txt
index 996ca5866c..8d5dd76e08 100644
--- a/crates/compiler/test_mono/generated/tail_call_elimination.txt
+++ b/crates/compiler/test_mono/generated/tail_call_elimination.txt
@@ -1,10 +1,10 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Num.20 (#Attr.2, #Attr.3):
-    let Num.258 : I64 = lowlevel NumSub #Attr.2 #Attr.3;
-    ret Num.258;
+    let Num.257 : I64 = lowlevel NumSub #Attr.2 #Attr.3;
+    ret Num.257;
 
 procedure Test.1 (Test.15, Test.16):
     joinpoint Test.7 Test.2 Test.3:
diff --git a/crates/compiler/test_mono/generated/unreachable_void_constructor.txt b/crates/compiler/test_mono/generated/unreachable_void_constructor.txt
index 16b7d9807e..017064eed0 100644
--- a/crates/compiler/test_mono/generated/unreachable_void_constructor.txt
+++ b/crates/compiler/test_mono/generated/unreachable_void_constructor.txt
@@ -1,6 +1,6 @@
 procedure Bool.2 ():
-    let Bool.11 : Int1 = true;
-    ret Bool.11;
+    let Bool.23 : Int1 = true;
+    ret Bool.23;
 
 procedure Test.0 ():
     let Test.6 : Int1 = CallByName Bool.2;
diff --git a/crates/compiler/test_mono/generated/when_nested_maybe.txt b/crates/compiler/test_mono/generated/when_nested_maybe.txt
index e8e714e59e..4b2af8c406 100644
--- a/crates/compiler/test_mono/generated/when_nested_maybe.txt
+++ b/crates/compiler/test_mono/generated/when_nested_maybe.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.19 : I64 = 41i64;
diff --git a/crates/compiler/test_mono/generated/when_on_record.txt b/crates/compiler/test_mono/generated/when_on_record.txt
index 18381ca043..83aabd4e7f 100644
--- a/crates/compiler/test_mono/generated/when_on_record.txt
+++ b/crates/compiler/test_mono/generated/when_on_record.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.5 : I64 = 2i64;
diff --git a/crates/compiler/test_mono/generated/when_on_two_values.txt b/crates/compiler/test_mono/generated/when_on_two_values.txt
index 76a1f73339..14788ffbaf 100644
--- a/crates/compiler/test_mono/generated/when_on_two_values.txt
+++ b/crates/compiler/test_mono/generated/when_on_two_values.txt
@@ -1,6 +1,6 @@
 procedure Num.19 (#Attr.2, #Attr.3):
-    let Num.257 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
-    ret Num.257;
+    let Num.256 : I64 = lowlevel NumAdd #Attr.2 #Attr.3;
+    ret Num.256;
 
 procedure Test.0 ():
     let Test.15 : I64 = 3i64;
diff --git a/crates/compiler/test_mono/src/tests.rs b/crates/compiler/test_mono/src/tests.rs
index 4436c815f7..c66e9d5ca1 100644
--- a/crates/compiler/test_mono/src/tests.rs
+++ b/crates/compiler/test_mono/src/tests.rs
@@ -143,7 +143,6 @@ fn compiles_to_ir(test_name: &str, src: &str) {
     verify_procedures(test_name, layout_interner, procedures, main_fn_symbol);
 }
 
-#[cfg(debug_assertions)]
 fn verify_procedures<'a>(
     test_name: &str,
     interner: STLayoutInterner<'a>,
@@ -174,7 +173,7 @@ fn verify_procedures<'a>(
     use std::process::Command;
 
     let is_tracked = Command::new("git")
-        .args(&["ls-files", "--error-unmatch", &path])
+        .args(["ls-files", "--error-unmatch", &path])
         .output()
         .unwrap();
 
@@ -186,7 +185,7 @@ fn verify_procedures<'a>(
     }
 
     let has_changes = Command::new("git")
-        .args(&["diff", "--color=always", &path])
+        .args(["diff", "--color=always", &path])
         .output()
         .unwrap();
 
@@ -201,19 +200,6 @@ fn verify_procedures<'a>(
     }
 }
 
-// NOTE because the Show instance of module names is different in --release mode,
-// these tests would all fail. In the future, when we do interesting optimizations,
-// we'll likely want some tests for --release too.
-#[cfg(not(debug_assertions))]
-fn verify_procedures(
-    _expected: &str,
-    _interner: STLayoutInterner<'_>,
-    _procedures: MutMap<(Symbol, ProcLayout<'_>), Proc<'_>>,
-    _main_fn_symbol: Symbol,
-) {
-    // Do nothing
-}
-
 #[mono_test]
 fn ir_int_literal() {
     r#"
diff --git a/crates/compiler/types/src/pretty_print.rs b/crates/compiler/types/src/pretty_print.rs
index 67ff778cd6..bfe2126d98 100644
--- a/crates/compiler/types/src/pretty_print.rs
+++ b/crates/compiler/types/src/pretty_print.rs
@@ -30,7 +30,7 @@ static EMPTY_TAG_UNION: &str = "[]";
 /// List (List I64)
 ///
 /// Otherwise, parens are unnecessary.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Parens {
     InFn,
     InTypeParam,
diff --git a/crates/compiler/types/src/types.rs b/crates/compiler/types/src/types.rs
index 50fbfb6af1..943ca81a98 100644
--- a/crates/compiler/types/src/types.rs
+++ b/crates/compiler/types/src/types.rs
@@ -8,7 +8,7 @@ use roc_error_macros::internal_error;
 use roc_module::called_via::CalledVia;
 use roc_module::ident::{ForeignSymbol, Ident, Lowercase, TagName};
 use roc_module::low_level::LowLevel;
-use roc_module::symbol::{Interns, ModuleId, Symbol};
+use roc_module::symbol::{Interns, Symbol};
 use roc_region::all::{Loc, Region};
 use std::fmt;
 use std::fmt::Write;
@@ -2250,7 +2250,7 @@ pub enum Reason {
     },
 }
 
-#[derive(PartialEq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum Category {
     Lookup(Symbol),
     CallResult(Option<Symbol>, CalledVia),
@@ -2334,7 +2334,7 @@ impl AliasKind {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct AliasVar {
     pub name: Lowercase,
     pub var: Variable,
@@ -2518,15 +2518,14 @@ impl ErrorType {
     }
 }
 
-pub fn write_error_type(home: ModuleId, interns: &Interns, error_type: ErrorType) -> String {
+pub fn write_error_type(interns: &Interns, error_type: ErrorType) -> String {
     let mut buf = String::new();
-    write_error_type_help(home, interns, error_type, &mut buf, Parens::Unnecessary);
+    write_error_type_help(interns, error_type, &mut buf, Parens::Unnecessary);
 
     buf
 }
 
 fn write_error_type_help(
-    home: ModuleId,
     interns: &Interns,
     error_type: ErrorType,
     buf: &mut String,
@@ -2550,7 +2549,7 @@ fn write_error_type_help(
             for arg in arguments {
                 buf.push(' ');
 
-                write_error_type_help(home, interns, arg, buf, Parens::InTypeParam);
+                write_error_type_help(interns, arg, buf, Parens::InTypeParam);
             }
 
             if write_parens {
@@ -2576,7 +2575,7 @@ fn write_error_type_help(
                         buf.push('(');
                     }
                     buf.push_str("Num ");
-                    write_error_type_help(home, interns, other, buf, Parens::InTypeParam);
+                    write_error_type_help(interns, other, buf, Parens::InTypeParam);
 
                     if write_parens {
                         buf.push(')');
@@ -2594,7 +2593,7 @@ fn write_error_type_help(
             let mut it = arguments.into_iter().peekable();
 
             while let Some(arg) = it.next() {
-                write_error_type_help(home, interns, arg, buf, Parens::InFn);
+                write_error_type_help(interns, arg, buf, Parens::InFn);
                 if it.peek().is_some() {
                     buf.push_str(", ");
                 }
@@ -2602,7 +2601,7 @@ fn write_error_type_help(
 
             buf.push_str(" -> ");
 
-            write_error_type_help(home, interns, *result, buf, Parens::InFn);
+            write_error_type_help(interns, *result, buf, Parens::InFn);
 
             if write_parens {
                 buf.push(')');
@@ -2627,7 +2626,7 @@ fn write_error_type_help(
                     }
                 };
 
-                write_error_type_help(home, interns, content, buf, Parens::Unnecessary);
+                write_error_type_help(interns, content, buf, Parens::Unnecessary);
             }
 
             buf.push('}');
diff --git a/crates/editor/src/editor/main.rs b/crates/editor/src/editor/main.rs
index b345815db5..1095bcec47 100644
--- a/crates/editor/src/editor/main.rs
+++ b/crates/editor/src/editor/main.rs
@@ -507,7 +507,7 @@ fn read_main_roc_file(project_dir_path_opt: Option<&Path>) -> (PathBuf, String)
 
         if let Some(&roc_file_name) = roc_file_names.first() {
             let full_roc_file_path = project_dir_path.join(roc_file_name);
-            let file_as_str = std::fs::read_to_string(&Path::new(&full_roc_file_path))
+            let file_as_str = std::fs::read_to_string(Path::new(&full_roc_file_path))
                 .unwrap_or_else(|err| panic!("In the provided project {:?}, I found the roc file {:?}, but I failed to read it: {}", &project_dir_path, full_roc_file_path, err));
 
             (full_roc_file_path, file_as_str)
diff --git a/crates/editor/src/graphics/lowlevel/buffer.rs b/crates/editor/src/graphics/lowlevel/buffer.rs
index 76f26e0480..593309460e 100644
--- a/crates/editor/src/graphics/lowlevel/buffer.rs
+++ b/crates/editor/src/graphics/lowlevel/buffer.rs
@@ -42,7 +42,7 @@ impl QuadBufferBuilder {
         max_y: f32,
         color: [f32; 4],
     ) -> Self {
-        self.vertex_data.extend(&[
+        self.vertex_data.extend([
             Vertex {
                 position: (min_x, min_y).into(),
                 color,
@@ -60,7 +60,7 @@ impl QuadBufferBuilder {
                 color,
             },
         ]);
-        self.index_data.extend(&[
+        self.index_data.extend([
             self.current_quad * 4,
             self.current_quad * 4 + 1,
             self.current_quad * 4 + 2,
diff --git a/crates/highlight/src/highlight_parser.rs b/crates/highlight/src/highlight_parser.rs
index f096cf7cec..ff1efc1e79 100644
--- a/crates/highlight/src/highlight_parser.rs
+++ b/crates/highlight/src/highlight_parser.rs
@@ -233,7 +233,7 @@ pub mod highlight_tests {
         node_to_string_w_children(
             *highlight_defs("a = 0", &mut mark_node_pool)
                 .unwrap()
-                .get(0)
+                .first()
                 .unwrap(),
             &mut str_buffer,
             &mark_node_pool,
diff --git a/crates/linker/src/elf.rs b/crates/linker/src/elf.rs
index 29ac545944..3b59d08bd0 100644
--- a/crates/linker/src/elf.rs
+++ b/crates/linker/src/elf.rs
@@ -1597,7 +1597,7 @@ mod tests {
         // we need to compile the app first
         let output = std::process::Command::new(&zig)
             .current_dir(dir)
-            .args(&[
+            .args([
                 "build-obj",
                 "app.zig",
                 "-fPIC",
@@ -1637,7 +1637,7 @@ mod tests {
         // now we can compile the host (it uses libapp.so, hence the order here)
         let output = std::process::Command::new(&zig)
             .current_dir(dir)
-            .args(&[
+            .args([
                 "build-exe",
                 "libapp.so",
                 "host.zig",
@@ -1672,7 +1672,7 @@ mod tests {
         std::fs::copy(&dir.join("preprocessedhost"), &dir.join("final")).unwrap();
 
         surgery_elf(
-            &*roc_app,
+            &roc_app,
             &dir.join("metadata"),
             &dir.join("final"),
             false,
diff --git a/crates/linker/src/generate_dylib/macho.rs b/crates/linker/src/generate_dylib/macho.rs
index 4c80fb06eb..f1c6ba5342 100644
--- a/crates/linker/src/generate_dylib/macho.rs
+++ b/crates/linker/src/generate_dylib/macho.rs
@@ -47,7 +47,7 @@ pub fn create_dylib_macho(
     }
 
     std::fs::write(
-        &dummy_obj_file,
+        dummy_obj_file,
         out_object.write().expect("failed to build output object"),
     )
     .expect("failed to write object to file");
@@ -67,7 +67,7 @@ pub fn create_dylib_macho(
 
     let output = Command::new("ld")
         .args(ld_prefix_args)
-        .args(&[
+        .args([
             ld_flag_soname,
             dummy_lib_file.file_name().unwrap().to_str().unwrap(),
             dummy_obj_file.to_str().unwrap(),
diff --git a/crates/linker/src/lib.rs b/crates/linker/src/lib.rs
index b51b9703dd..841432f9ee 100644
--- a/crates/linker/src/lib.rs
+++ b/crates/linker/src/lib.rs
@@ -231,7 +231,7 @@ fn generate_import_library(stub_lib_path: &Path, custom_names: &[String]) {
     // > https://github.com/messense/implib-rs
     let output = std::process::Command::new(&zig)
         .current_dir(stub_lib_path.parent().unwrap())
-        .args(&[
+        .args([
             "dlltool",
             "-d",
             def_filename.to_str().unwrap(),
diff --git a/crates/linker/src/metadata.rs b/crates/linker/src/metadata.rs
index aa665988a0..9085ea15e1 100644
--- a/crates/linker/src/metadata.rs
+++ b/crates/linker/src/metadata.rs
@@ -8,13 +8,13 @@ use roc_collections::all::MutMap;
 use roc_error_macros::internal_error;
 use serde::{Deserialize, Serialize};
 
-#[derive(Serialize, Deserialize, PartialEq, Debug)]
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
 pub enum VirtualOffset {
     Absolute,
     Relative(u64),
 }
 
-#[derive(Serialize, Deserialize, PartialEq, Debug)]
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
 pub struct SurgeryEntry {
     pub file_offset: u64,
     pub virtual_offset: VirtualOffset,
@@ -25,7 +25,7 @@ pub struct SurgeryEntry {
 // I think a number of them can be combined to reduce string duplication.
 // Also I think a few of them aren't need.
 // For example, I think preprocessing can deal with all shifting and remove the need for added_byte_count.
-#[derive(Default, Serialize, Deserialize, PartialEq, Debug)]
+#[derive(Default, Serialize, Deserialize, PartialEq, Eq, Debug)]
 pub struct Metadata {
     pub app_functions: Vec<String>,
     // offset followed by address.
diff --git a/crates/linker/src/pe.rs b/crates/linker/src/pe.rs
index 211d249bcd..8a0846d8a2 100644
--- a/crates/linker/src/pe.rs
+++ b/crates/linker/src/pe.rs
@@ -1617,7 +1617,7 @@ mod test {
         // we need to compile the app first
         let output = std::process::Command::new(&zig)
             .current_dir(dir)
-            .args(&[
+            .args([
                 "build-obj",
                 "app.zig",
                 "-target",
@@ -1642,7 +1642,7 @@ mod test {
         let file = std::fs::File::open(dir.join("app.obj")).unwrap();
         let roc_app = unsafe { memmap2::Mmap::map(&file) }.unwrap();
 
-        let roc_app_sections = AppSections::from_data(&*roc_app);
+        let roc_app_sections = AppSections::from_data(&roc_app);
         let symbols = roc_app_sections.roc_symbols;
 
         // make the dummy dylib based on the app object
@@ -1653,7 +1653,7 @@ mod test {
         // now we can compile the host (it uses libapp.dll, hence the order here)
         let output = std::process::Command::new(&zig)
             .current_dir(dir)
-            .args(&[
+            .args([
                 "build-exe",
                 "libapp.dll",
                 "host.zig",
@@ -1689,7 +1689,7 @@ mod test {
 
         std::fs::copy(&dir.join("preprocessedhost"), &dir.join("app.exe")).unwrap();
 
-        surgery_pe(&dir.join("app.exe"), &dir.join("metadata"), &*roc_app);
+        surgery_pe(&dir.join("app.exe"), &dir.join("metadata"), &roc_app);
     }
 
     #[allow(dead_code)]
@@ -1731,7 +1731,7 @@ mod test {
 
         let output = std::process::Command::new("wine")
             .current_dir(dir)
-            .args(&["app.exe"])
+            .args(["app.exe"])
             .output()
             .unwrap();
 
@@ -1869,7 +1869,7 @@ mod test {
 
         let output = std::process::Command::new(&zig)
             .current_dir(dir)
-            .args(&[
+            .args([
                 "build-exe",
                 "host.zig",
                 "-lc",
diff --git a/crates/repl_eval/src/eval.rs b/crates/repl_eval/src/eval.rs
index dc76afcd91..38554598da 100644
--- a/crates/repl_eval/src/eval.rs
+++ b/crates/repl_eval/src/eval.rs
@@ -345,13 +345,8 @@ fn jit_to_ast_help<'a, A: ReplApp<'a>>(
     let result = match layout {
         Layout::Builtin(Builtin::Bool) => Ok(app.call_function(
             main_fn_name,
-            |mem: &A::Memory, num: bool| {
-                bool_to_ast(
-                    env,
-                    mem,
-                    num,
-                    env.subs.get_content_without_compacting(raw_var),
-                )
+            |_mem: &A::Memory, num: bool| {
+                bool_to_ast(env, num, env.subs.get_content_without_compacting(raw_var))
             },
         )),
         Layout::Builtin(Builtin::Int(int_width)) => {
@@ -362,13 +357,8 @@ fn jit_to_ast_help<'a, A: ReplApp<'a>>(
                 (Some(Alias(Symbol::NUM_UNSIGNED8, ..)), U8) => num_helper!(u8),
                 (_, U8) => {
                     // This is not a number, it's a tag union or something else
-                    app.call_function(main_fn_name, |mem: &A::Memory, num: u8| {
-                        byte_to_ast(
-                            env,
-                            mem,
-                            num,
-                            env.subs.get_content_without_compacting(raw_var),
-                        )
+                    app.call_function(main_fn_name, |_mem: &A::Memory, num: u8| {
+                        byte_to_ast(env, num, env.subs.get_content_without_compacting(raw_var))
                     })
                 }
                 // The rest are numbers... for now
@@ -582,7 +572,7 @@ fn addr_to_ast<'a, M: ReplAppMemory>(
             // num is always false at the moment.
             let num: bool = mem.deref_bool(addr);
 
-            bool_to_ast(env, mem, num, raw_content)
+            bool_to_ast(env, num, raw_content)
         }
         (_, Layout::Builtin(Builtin::Int(int_width))) => {
             use IntWidth::*;
@@ -1141,12 +1131,7 @@ fn unpack_two_element_tag_union(
     (tag_name1, payload_vars1, tag_name2, payload_vars2)
 }
 
-fn bool_to_ast<'a, M: ReplAppMemory>(
-    env: &Env<'a, '_>,
-    mem: &M,
-    value: bool,
-    content: &Content,
-) -> Expr<'a> {
+fn bool_to_ast<'a>(env: &Env<'a, '_>, value: bool, content: &Content) -> Expr<'a> {
     use Content::*;
 
     let arena = env.arena;
@@ -1176,7 +1161,7 @@ fn bool_to_ast<'a, M: ReplAppMemory>(
                         let content = env.subs.get_content_without_compacting(var);
 
                         let loc_payload = &*arena.alloc(Loc {
-                            value: bool_to_ast(env, mem, value, content),
+                            value: bool_to_ast(env, value, content),
                             region: Region::zero(),
                         });
 
@@ -1225,7 +1210,7 @@ fn bool_to_ast<'a, M: ReplAppMemory>(
         Alias(_, _, var, _) => {
             let content = env.subs.get_content_without_compacting(*var);
 
-            bool_to_ast(env, mem, value, content)
+            bool_to_ast(env, value, content)
         }
         other => {
             unreachable!("Unexpected FlatType {:?} in bool_to_ast", other);
@@ -1233,12 +1218,7 @@ fn bool_to_ast<'a, M: ReplAppMemory>(
     }
 }
 
-fn byte_to_ast<'a, M: ReplAppMemory>(
-    env: &mut Env<'a, '_>,
-    mem: &M,
-    value: u8,
-    content: &Content,
-) -> Expr<'a> {
+fn byte_to_ast<'a>(env: &mut Env<'a, '_>, value: u8, content: &Content) -> Expr<'a> {
     use Content::*;
 
     let arena = env.arena;
@@ -1268,7 +1248,7 @@ fn byte_to_ast<'a, M: ReplAppMemory>(
                         let content = env.subs.get_content_without_compacting(var);
 
                         let loc_payload = &*arena.alloc(Loc {
-                            value: byte_to_ast(env, mem, value, content),
+                            value: byte_to_ast(env, value, content),
                             region: Region::zero(),
                         });
 
@@ -1345,7 +1325,7 @@ fn byte_to_ast<'a, M: ReplAppMemory>(
         Alias(_, _, var, _) => {
             let content = env.subs.get_content_without_compacting(*var);
 
-            byte_to_ast(env, mem, value, content)
+            byte_to_ast(env, value, content)
         }
         other => {
             unreachable!("Unexpected FlatType {:?} in byte_to_ast", other);
diff --git a/crates/repl_expect/src/run.rs b/crates/repl_expect/src/run.rs
index 39044c45e6..af95645efb 100644
--- a/crates/repl_expect/src/run.rs
+++ b/crates/repl_expect/src/run.rs
@@ -239,7 +239,7 @@ fn run_expect_fx<'a, W: std::io::Write>(
 ) -> std::io::Result<bool> {
     use signal_hook::{consts::signal::SIGCHLD, consts::signal::SIGUSR1, iterator::Signals};
 
-    let mut signals = Signals::new(&[SIGCHLD, SIGUSR1]).unwrap();
+    let mut signals = Signals::new([SIGCHLD, SIGUSR1]).unwrap();
 
     match unsafe { libc::fork() } {
         0 => unsafe {
diff --git a/crates/repl_wasm/build.rs b/crates/repl_wasm/build.rs
index 93f869ef43..f7397754d7 100644
--- a/crates/repl_wasm/build.rs
+++ b/crates/repl_wasm/build.rs
@@ -20,7 +20,7 @@ fn main() {
     let platform_obj = build_wasm_platform(&out_dir, &source_path);
 
     let mut pre_linked_binary_path = PathBuf::from(std::env::var("OUT_DIR").unwrap());
-    pre_linked_binary_path.extend(&["pre_linked_binary"]);
+    pre_linked_binary_path.extend(["pre_linked_binary"]);
     pre_linked_binary_path.set_extension("o");
 
     let output = Command::new(&zig_executable())
diff --git a/crates/reporting/tests/test_reporting.rs b/crates/reporting/tests/test_reporting.rs
index 6f82759b09..997d714d84 100644
--- a/crates/reporting/tests/test_reporting.rs
+++ b/crates/reporting/tests/test_reporting.rs
@@ -4847,14 +4847,27 @@ mod test_reporting {
             "#
         ),
         @r###"
-    ── MISSING EXPRESSION ───────────────────── tmp/pattern_binds_keyword/Test.roc ─
+    ── MISSING ARROW ────────────────────────── tmp/pattern_binds_keyword/Test.roc ─
 
-    I am partway through parsing a `when` expression, but I got stuck here:
+    I am partway through parsing a `when` expression, but got stuck here:
 
     5│          Just when ->
-                           ^
+                     ^
 
-    I was expecting to see an expression like 42 or "hello".
+    I was expecting to see an arrow next.
+
+    Note: Sometimes I get confused by indentation, so try to make your `when`
+    look something like this:
+
+        when List.first plants is
+          Ok n ->
+            n
+
+          Err _ ->
+            200
+
+    Notice the indentation. All patterns are aligned, and each branch is
+    indented a bit more than the corresponding pattern. That is important!
     "###
     );
 
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index b433a05442..f0e99282c3 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -4,7 +4,7 @@ use std::path::PathBuf;
 #[doc(hidden)]
 pub use pretty_assertions::assert_eq as _pretty_assert_eq;
 
-#[derive(PartialEq)]
+#[derive(PartialEq, Eq)]
 pub struct DebugAsDisplay<T>(pub T);
 
 impl<T: std::fmt::Display> std::fmt::Debug for DebugAsDisplay<T> {
@@ -32,7 +32,7 @@ impl TmpDir {
         let path = std::path::Path::new(dir);
         // ensure_empty_dir will fail if the dir doesn't already exist
         std::fs::create_dir_all(path).unwrap();
-        remove_dir_all::ensure_empty_dir(&path).unwrap();
+        remove_dir_all::ensure_empty_dir(path).unwrap();
 
         let mut pathbuf = std::path::PathBuf::new();
         pathbuf.push(path);
diff --git a/crates/vendor/morphic_lib/src/analyze.rs b/crates/vendor/morphic_lib/src/analyze.rs
index 498a2c279b..44f58da4ad 100644
--- a/crates/vendor/morphic_lib/src/analyze.rs
+++ b/crates/vendor/morphic_lib/src/analyze.rs
@@ -1562,11 +1562,11 @@ impl Query {
         }
         hasher.update((self.arg_slots_touched.len() as u64).to_le_bytes());
         for &arg_touched in &self.arg_slots_touched {
-            hasher.update(&[arg_touched as u8]);
+            hasher.update([arg_touched as u8]);
         }
         hasher.update((self.ret_slots_touched.len() as u64).to_le_bytes());
         for &ret_touched in &self.ret_slots_touched {
-            hasher.update(&[ret_touched as u8]);
+            hasher.update([ret_touched as u8]);
         }
         api::FuncSpec(hasher.finalize().into())
     }
@@ -1775,7 +1775,7 @@ pub(crate) fn analyze(tc: TypeCache, program: &ir::Program) -> ProgramSolutions
 fn hash_func_id_trivial(func_id: FuncId) -> api::FuncSpec {
     use sha2::{Digest, Sha256};
     let mut hasher = Sha256::new();
-    hasher.update(&func_id.0.to_le_bytes());
+    hasher.update(func_id.0.to_le_bytes());
     api::FuncSpec(hasher.finalize().into())
 }
 
diff --git a/crates/vendor/morphic_lib/src/api.rs b/crates/vendor/morphic_lib/src/api.rs
index b93180764c..70ec8efa19 100644
--- a/crates/vendor/morphic_lib/src/api.rs
+++ b/crates/vendor/morphic_lib/src/api.rs
@@ -1654,7 +1654,7 @@ pub fn solve_trivial(api_program: Program) -> Result<Solutions> {
 // solutions
 fn hash_bstr(hasher: &mut Sha256, bstr: &[u8]) {
     let header = (bstr.len() as u64).to_le_bytes();
-    hasher.update(&header);
+    hasher.update(header);
     hasher.update(bstr);
 }
 
diff --git a/examples/ruby-interop/README.md b/examples/ruby-interop/README.md
index 6257894786..d95a2c9d0d 100644
--- a/examples/ruby-interop/README.md
+++ b/examples/ruby-interop/README.md
@@ -49,10 +49,9 @@ You can now try this out in Ruby's REPL (`irb`), like so:
 ```sh
 $ irb
 irb(main):001:0> require_relative 'demo'
-Ruby just required Roc. Let's get READY TO ROC.
 => true
-irb(main):002:0> RocStuff::hello 'Hello, World'
-=> "Hello, World, OH YEAH!!! 🤘🤘"
+irb(main):002:0> RocApp::call_roc 42
+=> "The number was 42, OH YEAH!!! 🤘🤘"
 ```
 
 ## Rebuilding after Changes
diff --git a/examples/ruby-interop/demo.c b/examples/ruby-interop/demo.c
index f0572368f0..b5afb29419 100644
--- a/examples/ruby-interop/demo.c
+++ b/examples/ruby-interop/demo.c
@@ -2,6 +2,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 #include <unistd.h>
 #include <ruby.h>
@@ -19,10 +20,7 @@ void roc_dealloc(void *ptr, unsigned int alignment) { free(ptr); }
 
 __attribute__((noreturn)) void roc_panic(void *ptr, unsigned int alignment)
 {
-    char *msg = (char *)ptr;
-    fprintf(stderr,
-            "Application crashed with message\n\n    %s\n\nShutting down\n", msg);
-    exit(0);
+    rb_raise(rb_eException, "%s", (char *)ptr);
 }
 
 void *roc_memcpy(void *dest, const void *src, size_t n)
@@ -32,42 +30,142 @@ void *roc_memcpy(void *dest, const void *src, size_t n)
 
 void *roc_memset(void *str, int c, size_t n) { return memset(str, c, n); }
 
-struct RocStr
+// Reference counting
+
+// If the refcount is set to this, that means the allocation is
+// stored in readonly memory in the binary, and we must not
+// attempt to increment or decrement it; if we do, we'll segfault!
+const ssize_t REFCOUNT_READONLY = 0;
+const ssize_t REFCOUNT_ONE = (ssize_t)PTRDIFF_MIN;
+const size_t MASK = (size_t)PTRDIFF_MIN;
+
+// Increment reference count, given a pointer to the first element in a collection.
+// We don't need to check for overflow because in order to overflow a usize worth of refcounts,
+// you'd need to somehow have more pointers in memory than the OS's virtual address space can hold.
+void incref(uint8_t* bytes, uint32_t alignment)
 {
-    char *bytes;
+    ssize_t *refcount_ptr = ((ssize_t *)bytes) - 1;
+    ssize_t refcount = *refcount_ptr;
+
+    if (refcount != REFCOUNT_READONLY) {
+        *refcount_ptr = refcount + 1;
+    }
+}
+
+// Decrement reference count, given a pointer to the first element in a collection.
+// Then call roc_dealloc if nothing is referencing this collection anymore.
+void decref(uint8_t* bytes, uint32_t alignment)
+{
+    if (bytes == NULL) {
+        return;
+    }
+
+    size_t extra_bytes = (sizeof(size_t) >= (size_t)alignment) ? sizeof(size_t) : (size_t)alignment;
+    ssize_t *refcount_ptr = ((ssize_t *)bytes) - 1;
+    ssize_t refcount = *refcount_ptr;
+
+    if (refcount != REFCOUNT_READONLY) {
+        *refcount_ptr = refcount - 1;
+
+        if (refcount == REFCOUNT_ONE) {
+            void *original_allocation = (void *)(refcount_ptr - (extra_bytes - sizeof(size_t)));
+
+            roc_dealloc(original_allocation, alignment);
+        }
+    }
+}
+
+// RocBytes (List U8)
+
+struct RocBytes
+{
+    uint8_t *bytes;
     size_t len;
     size_t capacity;
 };
 
-struct RocStr init_rocstr(char *bytes, size_t len)
+struct RocBytes init_rocbytes(uint8_t *bytes, size_t len)
 {
-    struct RocStr ret;
-
-    if (len < sizeof(struct RocStr))
+    if (len == 0)
     {
-        // This is a small string. TODO do small string things.
-        size_t refcount_size = sizeof(size_t);
-        char *new_content = (char *)roc_alloc(len + refcount_size, alignof(size_t)) - refcount_size;
+        struct RocBytes ret = {
+            .len = 0,
+            .bytes = NULL,
+            .capacity = MASK,
+        };
 
-        roc_memcpy(new_content, bytes, len);
-
-        ret.bytes = new_content;
-        ret.len = len;
-        ret.capacity = len;
+        return ret;
     }
     else
     {
+        struct RocBytes ret;
         size_t refcount_size = sizeof(size_t);
-        char *new_content = (char *)roc_alloc(len + refcount_size, alignof(size_t)) - refcount_size;
+        uint8_t *new_content = (uint8_t *)roc_alloc(len + refcount_size, alignof(size_t)) + refcount_size;
 
-        roc_memcpy(new_content, bytes, len);
+        memcpy(new_content, bytes, len);
 
         ret.bytes = new_content;
         ret.len = len;
         ret.capacity = len;
-    }
 
-    return ret;
+        return ret;
+    }
+}
+
+// RocStr
+
+struct RocStr
+{
+    uint8_t *bytes;
+    size_t len;
+    size_t capacity;
+};
+
+struct RocStr init_rocstr(uint8_t *bytes, size_t len)
+{
+    if (len == 0)
+    {
+        struct RocStr ret = {
+            .len = 0,
+            .bytes = NULL,
+            .capacity = MASK,
+        };
+
+        return ret;
+    }
+    else if (len < sizeof(struct RocStr))
+    {
+        // Start out with zeroed memory, so that
+        // if we end up comparing two small RocStr values
+        // for equality, we won't risk memory garbage resulting
+        // in two equal strings appearing unequal.
+        struct RocStr ret = {
+            .len = 0,
+            .bytes = NULL,
+            .capacity = MASK,
+        };
+
+        // Copy the bytes into the stack allocation
+        memcpy(&ret, bytes, len);
+
+        // Record the string's length in the last byte of the stack allocation
+        ((uint8_t *)&ret)[sizeof(struct RocStr) - 1] = (uint8_t)len | 0b10000000;
+
+        return ret;
+    }
+    else
+    {
+        // A large RocStr is the same as a List U8 (aka RocBytes) in memory.
+        struct RocBytes roc_bytes = init_rocbytes(bytes, len);
+
+        struct RocStr ret = {
+            .len = roc_bytes.len,
+            .bytes = roc_bytes.bytes,
+            .capacity = roc_bytes.capacity,
+        };
+
+        return ret;
+    }
 }
 
 bool is_small_str(struct RocStr str) { return ((ssize_t)str.capacity) < 0; }
@@ -76,9 +174,9 @@ bool is_small_str(struct RocStr str) { return ((ssize_t)str.capacity) < 0; }
 // account the small string optimization
 size_t roc_str_len(struct RocStr str)
 {
-    char *bytes = (char *)&str;
-    char last_byte = bytes[sizeof(str) - 1];
-    char last_byte_xored = last_byte ^ 0b10000000;
+    uint8_t *bytes = (uint8_t *)&str;
+    uint8_t last_byte = bytes[sizeof(str) - 1];
+    uint8_t last_byte_xored = last_byte ^ 0b10000000;
     size_t small_len = (size_t)(last_byte_xored);
     size_t big_len = str.len;
 
@@ -95,45 +193,38 @@ size_t roc_str_len(struct RocStr str)
     }
 }
 
-extern void roc__mainForHost_1_exposed_generic(struct RocStr *ret, struct RocStr *arg);
+extern void roc__mainForHost_1_exposed_generic(struct RocBytes *ret, struct RocBytes *arg);
 
-VALUE hello(VALUE self, VALUE rb_arg)
+// Receive a value from Ruby, JSON serialized it and pass it to Roc as a List U8
+// (at which point the Roc platform will decode it and crash if it's invalid,
+// which roc_panic will translate into a Ruby exception), then get some JSON back from Roc
+// - also as a List U8 - and have Ruby JSON.parse it into a plain Ruby value to return.
+VALUE call_roc(VALUE self, VALUE rb_arg)
 {
-    // Verify the argument is a Ruby string; raise a type error if not.
-    if (TYPE(rb_arg) != T_STRING)
-    {
-        rb_raise(rb_eTypeError, "`hello` only accepts strings.");
-    }
+    // This must be required before the to_json method will exist on String.
+    rb_require("json");
 
-    struct RocStr arg = init_rocstr(RSTRING_PTR(rb_arg), RSTRING_LEN(rb_arg));
-    struct RocStr ret;
+    // Turn the given Ruby value into a JSON string.
+    // TODO should we defensively encode it as UTF-8 first?
+    VALUE json_arg = rb_funcall(rb_arg, rb_intern("to_json"), 0);
 
+    struct RocBytes arg = init_rocbytes((uint8_t *)RSTRING_PTR(json_arg), RSTRING_LEN(json_arg));
+    struct RocBytes ret;
+
+    // Call the Roc function to populate `ret`'s bytes.
     roc__mainForHost_1_exposed_generic(&ret, &arg);
 
-    // Determine str_len and the str_bytes pointer,
-    // taking into account the small string optimization.
-    size_t str_len = roc_str_len(ret);
-    VALUE ruby_str;
+    // Create a rb_utf8_str from the heap-allocated JSON bytes the Roc function returned.
+    VALUE returned_json = rb_utf8_str_new((char *)ret.bytes, ret.len);
 
-    if (is_small_str(ret))
-    {
-        ruby_str = rb_utf8_str_new((char *)&ret, str_len);
-    }
-    else
-    {
-        ruby_str = rb_utf8_str_new(ret.bytes, str_len);
+    // Now that we've created our Ruby JSON string, we're no longer referencing the RocBytes.
+    decref((void *)&ret, alignof(uint8_t *));
 
-        // TODO decrement refcount and then only dealloc if that was the last reference
-        roc_dealloc(ret.bytes - sizeof(size_t), alignof(char *));
-    }
-
-    return ruby_str;
+    return rb_funcall(rb_define_module("JSON"), rb_intern("parse"), 1, returned_json);
 }
 
 void Init_demo()
 {
-    printf("Ruby just required Roc. Let's get READY TO ROC.\n");
-
-    VALUE roc_stuff = rb_define_module("RocStuff");
-    rb_define_module_function(roc_stuff, "hello", &hello, 1);
+    VALUE roc_app = rb_define_module("RocApp");
+    rb_define_module_function(roc_app, "call_roc", &call_roc, 1);
 }
diff --git a/examples/ruby-interop/main.roc b/examples/ruby-interop/main.roc
index f0ccd64238..9b9d316dca 100644
--- a/examples/ruby-interop/main.roc
+++ b/examples/ruby-interop/main.roc
@@ -1,11 +1,13 @@
 app "libhello"
     packages { pf: "platform/main.roc" }
     imports []
-    provides [makeItRoc] to pf
+    provides [main] to pf
 
-makeItRoc : Str -> Str
-makeItRoc = \str ->
-    if Str.isEmpty str then
-        "I need a string here!"
+main : U64 -> Str
+main = \num ->
+    if num == 0 then
+        "I need a positive number here!"
     else
-        "\(str), OH YEAH!!! 🤘🤘"
+        str = Num.toStr num
+
+        "The number was \(str), OH YEAH!!! 🤘🤘"
diff --git a/examples/ruby-interop/platform/main.roc b/examples/ruby-interop/platform/main.roc
index 339ef9eb61..c26447e0d3 100644
--- a/examples/ruby-interop/platform/main.roc
+++ b/examples/ruby-interop/platform/main.roc
@@ -1,9 +1,12 @@
-platform "hello-world"
-    requires {} { makeItRoc : Str -> Str }
+platform "ruby-interop"
+    requires {} { main : arg -> ret | arg has Decoding, ret has Encoding }
     exposes []
     packages {}
-    imports []
+    imports [Json]
     provides [mainForHost]
 
-mainForHost : Str -> Str
-mainForHost = \str -> makeItRoc str
+mainForHost : List U8 -> List U8
+mainForHost = \json ->
+    when Decode.fromBytes json Json.fromUtf8 is
+        Ok arg -> Encode.toBytes (main arg) Json.toUtf8
+        Err _ -> [] # TODO panic so that Ruby raises an exception