Merge branch 'main' into simplify-refcount

Signed-off-by: Brendan Hansknecht <Brendan.Hansknecht@gmail.com>
2025-08-03 19:58:18 +00:00 · 2025-01-10 20:34:52 -08:00 · 2025-01-10 20:34:52 -08:00 · 7643f89781
commit 7643f89781
parent d9d2ce83d6 1bb9f7f530
131 changed files with 2464 additions and 2148 deletions
--- a/.github/workflows/www.yml
+++ b/.github/workflows/www.yml
@ -1,21 +1,24 @@
 name: deploy www.roc-lang.org

-# Whenever a commit lands on `main`, deploy the site
 on:
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+  # Whenever a commit lands on `main`, deploy the site
  push:
    branches:
      - deploy-www

 jobs:
  deploy:
-    name: 'Deploy to Netlify'
+    name: "Deploy to Netlify"
    runs-on: [self-hosted, linux]
    steps:
      - uses: jsmrcaga/action-netlify-deploy@v1.6.0
        with:
-          install_command: 'pwd; cd ../../www'
-          build_command: 'bash build.sh'
-          build_directory: 'build'
+          install_command: "pwd; cd ../../www"
+          build_command: "bash build.sh"
+          build_directory: "build"
          NETLIFY_AUTH_TOKEN: ${{ secrets.NETLIFY_AUTH_TOKEN }}
          NETLIFY_SITE_ID: ${{ secrets.NETLIFY_SITE_ID }}
          NETLIFY_DEPLOY_MESSAGE: "Deploy git ref ${{ github.ref }}"
--- a/crates/cli/src/format.rs
+++ b/crates/cli/src/format.rs
@ -278,14 +278,14 @@ import pf.Stdin
 main =
    Stdout.line! "What's your name?"
    name = Stdin.line!
-    Stdout.line! "Hi $(name)!""#;
+    Stdout.line! "Hi ${name}!""#;

    const UNFORMATTED_ROC: &str = r#"app [main] { pf: platform "platform/main.roc" }

 main =
        Stdout.line! "What's your name?"
        name = Stdin.line!
-        Stdout.line! "Hi $(name)!"
+        Stdout.line! "Hi ${name}!"
 "#;

    fn setup_test_file(dir: &Path, file_name: &str, contents: &str) -> PathBuf {
--- a/crates/cli/tests/benchmarks/Quicksort.roc
+++ b/crates/cli/tests/benchmarks/Quicksort.roc
@ -10,7 +10,7 @@ show = \list ->
            |> List.map(Num.to_str)
            |> Str.join_with(", ")

-        "[$(content)]"
+        "[${content}]"

 sort_by : List a, (a -> Num *) -> List a
 sort_by = \list, to_comparable ->
--- a/crates/cli/tests/benchmarks/rBTreeInsert.roc
+++ b/crates/cli/tests/benchmarks/rBTreeInsert.roc
@ -25,7 +25,7 @@ show_rb_tree = \tree, show_key, show_value ->
            s_l = node_in_parens(left, show_key, show_value)
            s_r = node_in_parens(right, show_key, show_value)

-            "Node $(s_color) $(s_key) $(s_value) $(s_l) $(s_r)"
+            "Node ${s_color} ${s_key} ${s_value} ${s_l} ${s_r}"

 node_in_parens : RedBlackTree k v, (k -> Str), (v -> Str) -> Str
 node_in_parens = \tree, show_key, show_value ->
@ -36,7 +36,7 @@ node_in_parens = \tree, show_key, show_value ->
        Node(_, _, _, _, _) ->
            inner = show_rb_tree(tree, show_key, show_value)

-            "($(inner))"
+            "(${inner})"

 show_color : NodeColor -> Str
 show_color = \color ->
--- a/crates/cli/tests/snapshots/cli_tests__cli_tests__test_platform_simple_zig__module_params_arity_mismatch.snap
+++ b/crates/cli/tests/snapshots/cli_tests__cli_tests__test_platform_simple_zig__module_params_arity_mismatch.snap
@ -8,7 +8,7 @@ snapshot_kind: text

 The get_user function expects 1 argument, but it got 2 instead:

-12│      $(Api.get_user(1, 2))
+12│      ${Api.get_user(1, 2)}
           ^^^^^^^^^^^^

 Are there any missing commas? Or missing parentheses?
@ -18,7 +18,7 @@ Are there any missing commas? Or missing parentheses?

 This value is not a function, but it was given 1 argument:

-13│      $(Api.base_url(1))
+13│      ${Api.base_url(1)}
           ^^^^^^^^^^^^

 Are there any missing commas? Or missing parentheses?
@ -28,7 +28,7 @@ Are there any missing commas? Or missing parentheses?

 The get_post_comment function expects 2 arguments, but it got only 1:

-16│      $(Api.get_post_comment(1))
+16│      ${Api.get_post_comment(1)}
           ^^^^^^^^^^^^^^^^^^^^

 Roc does not allow functions to be partially applied. Use a closure to
--- a/crates/cli/tests/snapshots/cli_tests__cli_tests__test_platform_simple_zig__module_params_bad_ann.snap
+++ b/crates/cli/tests/snapshots/cli_tests__cli_tests__test_platform_simple_zig__module_params_bad_ann.snap
@ -11,7 +11,7 @@ fn_annotated_as_value definition:

 3│   fn_annotated_as_value : Str
 4│>  fn_annotated_as_value = \post_id, comment_id ->
-5│>      "/posts/$(post_id)/comments/$(Num.to_str(comment_id))"
+5│>      "/posts/${post_id}/comments/${Num.to_str(comment_id)}"

 The body is an anonymous function of type:

@ -28,7 +28,7 @@ Something is off with the body of the missing_arg definition:

 7│   missing_arg : Str -> Str
 8│>  missing_arg = \post_id, _ ->
-9│>      "/posts/$(post_id)/comments"
+9│>      "/posts/${post_id}/comments"

 The body is an anonymous function of type:

--- a/crates/cli/tests/snapshots/cli_tests__cli_tests__test_platform_simple_zig__module_params_unexpected_fn.snap
+++ b/crates/cli/tests/snapshots/cli_tests__cli_tests__test_platform_simple_zig__module_params_unexpected_fn.snap
@ -8,7 +8,7 @@ snapshot_kind: text

 This argument to this string interpolation has an unexpected type:

-10│      "$(Api.get_post)"
+10│      "${Api.get_post}"
            ^^^^^^^^^^^^

 The argument is an anonymous function of type:
--- a/crates/cli/tests/test-projects/effectful/combine-tasks.roc
+++ b/crates/cli/tests/test-projects/effectful/combine-tasks.roc
@ -12,7 +12,7 @@ main =
            _: Task.ok(Dict.single("a", "b")),
        }!

-    Stdout.line!("For multiple tasks: $(Inspect.to_str(multiple_in))")
+    Stdout.line!("For multiple tasks: ${Inspect.to_str(multiple_in)}")

 sequential : Task a err, Task b err, (a, b -> c) -> Task c err
 sequential = \first_task, second_task, mapper ->
--- a/crates/cli/tests/test-projects/effectful/for_each_try.roc
+++ b/crates/cli/tests/test-projects/effectful/for_each_try.roc
@ -15,8 +15,8 @@ main! = \{} ->
 validate! : U32 => Result {} U32
 validate! = \x ->
    if Num.is_even(x) then
-        Effect.put_line!("✅ $(Num.to_str(x))")
+        Effect.put_line!("✅ ${Num.to_str(x)}")
        Ok({})
    else
-        Effect.put_line!("$(Num.to_str(x)) is not even! ABORT!")
+        Effect.put_line!("${Num.to_str(x)} is not even! ABORT!")
        Err(x)
--- a/crates/cli/tests/test-projects/effectful/form.roc
+++ b/crates/cli/tests/test-projects/effectful/form.roc
@ -7,7 +7,7 @@ main! = \{} ->
    first = ask!("What's your first name?")
    last = ask!("What's your last name?")

-    Effect.put_line!("\nHi, $(first) $(last)!\n")
+    Effect.put_line!("\nHi, ${first} ${last}!\n")

    when Str.to_u8(ask!("How old are you?")) is
        Err(InvalidNumStr) ->
@ -17,7 +17,7 @@ main! = \{} ->
            Effect.put_line!("\nNice! You can vote!")

        Ok(age) ->
-            Effect.put_line!("\nYou'll be able to vote in $(Num.to_str((18 - age))) years")
+            Effect.put_line!("\nYou'll be able to vote in ${Num.to_str(18 - age)} years")

    Effect.put_line!("\nBye! 👋")

--- a/crates/cli/tests/test-projects/effectful/print-line.roc
+++ b/crates/cli/tests/test-projects/effectful/print-line.roc
@ -15,5 +15,5 @@ main! = \{} ->
    else
        {}

-    Effect.put_line!("You entered: $(line)")
+    Effect.put_line!("You entered: ${line}")
    Effect.put_line!("It is known")
--- a/crates/cli/tests/test-projects/effectful/suffixed_record_field.roc
+++ b/crates/cli/tests/test-projects/effectful/suffixed_record_field.roc
@ -18,5 +18,5 @@ main! = \{} ->
        get_line!: Effect.get_line!,
    }

-    Effect.put_line!("not_effectful: $(not_effectful.get_line!({}))")
-    Effect.put_line!("effectful: $(effectful.get_line!({}))")
+    Effect.put_line!("not_effectful: ${not_effectful.get_line!({})}")
+    Effect.put_line!("effectful: ${effectful.get_line!({})}")
--- a/crates/cli/tests/test-projects/effectful/untyped_passed_fx.roc
+++ b/crates/cli/tests/test-projects/effectful/untyped_passed_fx.roc
@ -7,6 +7,6 @@ main! = \{} ->
    logged!("hello", \{} -> Effect.put_line!("Hello, World!"))

 logged! = \name, fx! ->
-    Effect.put_line!("Before $(name)")
+    Effect.put_line!("Before ${name}")
    fx!({})
-    Effect.put_line!("After $(name)")
+    Effect.put_line!("After ${name}")
--- a/crates/cli/tests/test-projects/false-interpreter/Context.roc
+++ b/crates/cli/tests/test-projects/false-interpreter/Context.roc
@ -56,7 +56,7 @@ to_str = \{ scopes, stack, state, vars } ->
    stack_str = Str.join_with(List.map(stack, to_str_data), " ")
    vars_str = Str.join_with(List.map(vars, to_str_data), " ")

-    "\n============\nDepth: $(depth)\nState: $(state_str)\nStack: [$(stack_str)]\nVars: [$(vars_str)]\n============\n"
+    "\n============\nDepth: ${depth}\nState: ${state_str}\nStack: [${stack_str}]\nVars: [${vars_str}]\n============\n"

 with! : Str, (Context => a) => a
 with! = \path, callback! ->
--- a/crates/cli/tests/test-projects/false-interpreter/main.roc
+++ b/crates/cli/tests/test-projects/false-interpreter/main.roc
@ -21,7 +21,7 @@ main! = \filename ->
            {}

        Err(StringErr(e)) ->
-            Stdout.line!("Ran into problem:\n$(e)\n")
+            Stdout.line!("Ran into problem:\n${e}\n")

 interpret_file! : Str => Result {} [StringErr Str]
 interpret_file! = \filename ->
@ -44,7 +44,7 @@ interpret_file! = \filename ->
                Err(StringErr("Ran into an invalid boolean that was neither false (0) or true (-1)"))

            Err(InvalidChar(char)) ->
-                Err(StringErr("Ran into an invalid character with ascii code: $(char)"))
+                Err(StringErr("Ran into an invalid character with ascii code: ${char}"))

            Err(MaxInputNumber) ->
                Err(StringErr("Like the original false compiler, the max input number is 320,000"))
--- a/crates/cli/tests/test-projects/fixtures/packages/main.roc
+++ b/crates/cli/tests/test-projects/fixtures/packages/main.roc
@ -7,4 +7,4 @@ app [main] {
 import json.JsonParser
 import csv.Csv

-main = "Hello, World! $(JsonParser.example) $(Csv.example)"
+main = "Hello, World! ${JsonParser.example} ${Csv.example}"
--- a/crates/cli/tests/test-projects/fixtures/transitive-deps/direct-one-and-two.roc
+++ b/crates/cli/tests/test-projects/fixtures/transitive-deps/direct-one-and-two.roc
@ -7,4 +7,4 @@ app [main] {
 import one.One
 import two.Two

-main = "$(One.example) | $(Two.example)"
+main = "${One.example} | ${Two.example}"
--- a/crates/cli/tests/test-projects/fixtures/transitive-deps/one/One.roc
+++ b/crates/cli/tests/test-projects/fixtures/transitive-deps/one/One.roc
@ -2,4 +2,4 @@ module [example]

 import two.Two

-example = "[One imports Two: $(Two.example)]"
+example = "[One imports Two: ${Two.example}]"
--- a/crates/cli/tests/test-projects/fixtures/transitive-deps/zero/Zero.roc
+++ b/crates/cli/tests/test-projects/fixtures/transitive-deps/zero/Zero.roc
@ -2,4 +2,4 @@ module [example]

 import one.One

-example = "[Zero imports One: $(One.example)]"
+example = "[Zero imports One: ${One.example}]"
--- a/crates/cli/tests/test-projects/module_params/Api.roc
+++ b/crates/cli/tests/test-projects/module_params/Api.roc
@ -14,18 +14,18 @@ module { app_id, protocol } -> [
 ## value def referencing params
 base_url : Str
 base_url =
-    protocol("api.example.com/$(app_id)")
+    protocol("api.example.com/${app_id}")

 ## function def referencing params
 get_user : U32 -> Str
 get_user = \user_id ->
    # purposefully not using baseUrl to test top-level fn referencing param
-    protocol("api.example.com/$(app_id)/users/$(Num.to_str(user_id))")
+    protocol("api.example.com/${app_id}/users/${Num.to_str(user_id)}")

 ## function def referencing top-level value
 get_post : U32 -> Str
 get_post = \post_id ->
-    "$(base_url)/posts/$(Num.to_str(post_id))"
+    "${base_url}/posts/${Num.to_str(post_id)}"

 ## function def passing top-level function
 get_posts : List U32 -> List Str
@ -35,13 +35,13 @@ get_posts = \ids ->
 ## function def calling top-level function
 get_post_comments : U32 -> Str
 get_post_comments = \post_id ->
-    "$(get_post(post_id))/comments"
+    "${get_post(post_id)}/comments"

 ## function def passing nested function
 get_companies : List U32 -> List Str
 get_companies = \ids ->
    get_company = \id ->
-        protocol("api.example.com/$(app_id)/companies/$(Num.to_str(id))")
+        protocol("api.example.com/${app_id}/companies/${Num.to_str(id)}")

    List.map(ids, get_company)

@ -59,11 +59,11 @@ get_post_aliased =
 get_user_safe : U32 -> Str
 get_user_safe =
    if Str.starts_with(app_id, "prod_") then
-        \id -> "$(get_user(id))?safe=true"
+        \id -> "${get_user(id)}?safe=true"
    else
        get_user

 ## two-argument function
 get_post_comment : U32, U32 -> Str
 get_post_comment = \post_id, comment_id ->
-    "$(get_post(post_id))/comments/$(Num.to_str(comment_id))"
+    "${get_post(post_id)}/comments/${Num.to_str(comment_id)}"
--- a/crates/cli/tests/test-projects/module_params/BadAnn.roc
+++ b/crates/cli/tests/test-projects/module_params/BadAnn.roc
@ -2,8 +2,8 @@ module { app_id } -> [fn_annotated_as_value, missing_arg]

 fn_annotated_as_value : Str
 fn_annotated_as_value = \post_id, comment_id ->
-    "/posts/$(post_id)/comments/$(Num.to_str(comment_id))"
+    "/posts/${post_id}/comments/${Num.to_str(comment_id)}"

 missing_arg : Str -> Str
 missing_arg = \post_id, _ ->
-    "/posts/$(post_id)/comments"
+    "/posts/${post_id}/comments"
--- a/crates/cli/tests/test-projects/module_params/ImportInExpect.roc
+++ b/crates/cli/tests/test-projects/module_params/ImportInExpect.roc
@ -1,6 +1,6 @@
 module []

-https = \url -> "https://$(url)"
+https = \url -> "https://${url}"

 expect
    import Api { app_id: "one", protocol: https }
--- a/crates/cli/tests/test-projects/module_params/Menu.roc
+++ b/crates/cli/tests/test-projects/module_params/Menu.roc
@ -4,4 +4,4 @@ menu = \name ->
    indirect(name)

 indirect = \name ->
-    echo("Hi, $(name)!")
+    echo("Hi, ${name}!")
--- a/crates/cli/tests/test-projects/module_params/app.roc
+++ b/crates/cli/tests/test-projects/module_params/app.roc
@ -6,8 +6,8 @@ import Api { app_id: "one", protocol: https } as App1
 import Api { app_id: "two", protocol: http } as App2
 import Api { app_id: "prod_1", protocol: http } as Prod

-https = \url -> "https://$(url)"
-http = \url -> "http://$(url)"
+https = \url -> "https://${url}"
+http = \url -> "http://${url}"

 users_app1 =
    # pass top-level fn in a module with params
@ -27,33 +27,33 @@ main =
        List.map([1, 2, 3], App3.get_user)

    """
-    App1.baseUrl: $(App1.base_url)
-    App2.baseUrl: $(App2.base_url)
-    App3.baseUrl: $(App3.base_url)
-    App1.getUser 1: $(App1.get_user(1))
-    App2.getUser 2: $(App2.get_user(2))
-    App3.getUser 3: $(App3.get_user(3))
-    App1.getPost 1: $(App1.get_post(1))
-    App2.getPost 2: $(App2.get_post(2))
-    App3.getPost 3: $(App3.get_post(3))
-    App1.getPosts [1, 2]: $(Inspect.to_str(App1.get_posts([1, 2])))
-    App2.getPosts [3, 4]: $(Inspect.to_str(App2.get_posts([3, 4])))
-    App2.getPosts [5, 6]: $(Inspect.to_str(App2.get_posts([5, 6])))
-    App1.getPostComments 1: $(App1.get_post_comments(1))
-    App2.getPostComments 2: $(App2.get_post_comments(2))
-    App2.getPostComments 3: $(App2.get_post_comments(3))
-    App1.getCompanies [1, 2]: $(Inspect.to_str(App1.get_companies([1, 2])))
-    App2.getCompanies [3, 4]: $(Inspect.to_str(App2.get_companies([3, 4])))
-    App2.getCompanies [5, 6]: $(Inspect.to_str(App2.get_companies([5, 6])))
-    App1.getPostAliased 1: $(App1.get_post_aliased(1))
-    App2.getPostAliased 2: $(App2.get_post_aliased(2))
-    App3.getPostAliased 3: $(App3.get_post_aliased(3))
-    App1.baseUrlAliased: $(App1.base_url_aliased)
-    App2.baseUrlAliased: $(App2.base_url_aliased)
-    App3.baseUrlAliased: $(App3.base_url_aliased)
-    App1.getUserSafe 1: $(App1.get_user_safe(1))
-    Prod.getUserSafe 2: $(Prod.get_user_safe(2))
-    usersApp1: $(Inspect.to_str(users_app1))
-    getUserApp3Nested 3: $(get_user_app3_nested(3))
-    usersApp3Passed: $(Inspect.to_str(users_app3_passed))
+    App1.baseUrl: ${App1.base_url}
+    App2.baseUrl: ${App2.base_url}
+    App3.baseUrl: ${App3.base_url}
+    App1.getUser 1: ${App1.get_user(1)}
+    App2.getUser 2: ${App2.get_user(2)}
+    App3.getUser 3: ${App3.get_user(3)}
+    App1.getPost 1: ${App1.get_post(1)}
+    App2.getPost 2: ${App2.get_post(2)}
+    App3.getPost 3: ${App3.get_post(3)}
+    App1.getPosts [1, 2]: ${Inspect.to_str(App1.get_posts([1, 2]))}
+    App2.getPosts [3, 4]: ${Inspect.to_str(App2.get_posts([3, 4]))}
+    App2.getPosts [5, 6]: ${Inspect.to_str(App2.get_posts([5, 6]))}
+    App1.getPostComments 1: ${App1.get_post_comments(1)}
+    App2.getPostComments 2: ${App2.get_post_comments(2)}
+    App2.getPostComments 3: ${App2.get_post_comments(3)}
+    App1.getCompanies [1, 2]: ${Inspect.to_str(App1.get_companies([1, 2]))}
+    App2.getCompanies [3, 4]: ${Inspect.to_str(App2.get_companies([3, 4]))}
+    App2.getCompanies [5, 6]: ${Inspect.to_str(App2.get_companies([5, 6]))}
+    App1.getPostAliased 1: ${App1.get_post_aliased(1)}
+    App2.getPostAliased 2: ${App2.get_post_aliased(2)}
+    App3.getPostAliased 3: ${App3.get_post_aliased(3)}
+    App1.baseUrlAliased: ${App1.base_url_aliased}
+    App2.baseUrlAliased: ${App2.base_url_aliased}
+    App3.baseUrlAliased: ${App3.base_url_aliased}
+    App1.getUserSafe 1: ${App1.get_user_safe(1)}
+    Prod.getUserSafe 2: ${Prod.get_user_safe(2)}
+    usersApp1: ${Inspect.to_str(users_app1)}
+    getUserApp3Nested 3: ${get_user_app3_nested(3)}
+    usersApp3Passed: ${Inspect.to_str(users_app3_passed)}
    """
--- a/crates/cli/tests/test-projects/module_params/arity_mismatch.roc
+++ b/crates/cli/tests/test-projects/module_params/arity_mismatch.roc
@ -4,14 +4,14 @@ app [main] {

 import Api { app_id: "one", protocol: https }

-https = \url -> "https://$(url)"
+https = \url -> "https://${url}"

 main =
    """
    # too many args
-    $(Api.get_user(1, 2))
-    $(Api.base_url(1))
+    ${Api.get_user(1, 2)}
+    ${Api.base_url(1)}

    # too few args
-    $(Api.get_post_comment(1))
+    ${Api.get_post_comment(1)}
    """
--- a/crates/cli/tests/test-projects/module_params/effect_module.roc
+++ b/crates/cli/tests/test-projects/module_params/effect_module.roc
@ -1,3 +1,3 @@
 module { stdout! } -> [log!]

-log! = \msg, level -> stdout!("$(level):$(msg)")
+log! = \msg, level -> stdout!("${level}:${msg}")
--- a/crates/cli/tests/test-projects/module_params/unexpected_fn.roc
+++ b/crates/cli/tests/test-projects/module_params/unexpected_fn.roc
@ -4,7 +4,7 @@ app [main] {

 import Api { app_id: "one", protocol: https }

-https = \url -> "https://$(url)"
+https = \url -> "https://${url}"

 main =
-    "$(Api.get_post)"
+    "${Api.get_post}"
--- a/crates/cli/tests/test-projects/platform_requires_pkg/platform/main.roc
+++ b/crates/cli/tests/test-projects/platform_requires_pkg/platform/main.roc
@ -11,4 +11,4 @@ import foo.Foo

 main_for_host : Str
 main_for_host =
-    "$(main) $(Foo.foo)"
+    "${main} ${Foo.foo}"
--- a/crates/compiler/builtins/bitcode/src/utils.zig
+++ b/crates/compiler/builtins/bitcode/src/utils.zig
@ -381,6 +381,7 @@ inline fn decref_ptr_to_refcount(
        switch (RC_TYPE) {
            .normal => {
                if (DEBUG_INCDEC and builtin.target.cpu.arch != .wasm32) {
+
                    const old = @as(usize, @bitCast(refcount));
                    const new = @as(usize, @bitCast(refcount_ptr[0] -% 1));

--- a/crates/compiler/builtins/roc/Dict.roc
+++ b/crates/compiler/builtins/roc/Dict.roc
@ -887,7 +887,7 @@ increase_size = \@Dict({ data, max_bucket_capacity, max_load_factor, shifts }) -
            },
        )
    else
-        crash("Dict hit limit of $(Num.to_str(max_bucket_count)) elements. Unable to grow more.")
+        crash("Dict hit limit of ${Num.to_str(max_bucket_count)} elements. Unable to grow more.")

 alloc_buckets_from_shift : U8, F32 -> (List Bucket, U64)
 alloc_buckets_from_shift = \shifts, max_load_factor ->
--- a/crates/compiler/builtins/roc/List.roc
+++ b/crates/compiler/builtins/roc/List.roc
@ -75,6 +75,7 @@ module [
    for_each!,
    for_each_try!,
    walk!,
+    walk_try!,
 ]

 import Bool exposing [Bool, Eq]
@ -1484,7 +1485,7 @@ for_each! = \list, func! ->
 ## List.for_each_try!(files_to_delete, \path ->
 ##     File.delete!(path)?
 ##
-##     Stdout.line!("$(path) deleted")
+##     Stdout.line!("${path} deleted")
 ## )
 ## ```
 for_each_try! : List a, (a => Result {} err) => Result {} err
@ -1514,7 +1515,40 @@ for_each_try! = \list, func! ->
 walk! : List elem, state, (state, elem => state) => state
 walk! = \list, state, func! ->
    when list is
-        [] -> state
+        [] ->
+            state
+
        [elem, .. as rest] ->
            next_state = func!(state, elem)
            walk!(rest, next_state, func!)
+
+## Build a value from the contents of a list, using an effectful function that might fail.
+##
+## If the function returns `Err`, the iteration stops and the error is returned.
+##
+## ```
+## names =
+##     List.walk_try!(
+##         ["First", "Middle", "Last"],
+##         [],
+##         \accumulator, which ->
+##             Stdout.write!("${which} name: ")?
+##             name = Stdin.line!({})?
+##             Ok(List.append(accumulator, name)),
+##     )?
+## ```
+##
+## This is the same as [walk_try], except that the step function can have effects.
+walk_try! : List elem, state, (state, elem => Result state err) => Result state err
+walk_try! = \list, state, func! ->
+    when list is
+        [] ->
+            Ok(state)
+
+        [elem, .. as rest] ->
+            when func!(state, elem) is
+                Ok(next_state) ->
+                    walk_try!(rest, next_state, func!)
+
+                Err(err) ->
+                    Err(err)
--- a/crates/compiler/builtins/roc/Result.roc
+++ b/crates/compiler/builtins/roc/Result.roc
@ -124,11 +124,12 @@ on_err = \result, transform ->
 ## Like [on_err], but it allows the transformation function to produce effects.
 ##
 ## ```roc
-## Result.on_err(Err("missing user"), (\msg ->
-##     Stdout.line!("ERROR: $(msg)")?
-##
-##     Err(msg)
-## ))
+## Result.on_err(
+##     Err("missing user"),
+##     \msg ->
+##         Stdout.line!("ERROR: ${msg}")?
+##         Err(msg),
+## )
 ## ```
 on_err! : Result a err, (err => Result a other_err) => Result a other_err
 on_err! = \result, transform! ->
--- a/crates/compiler/builtins/roc/Str.roc
+++ b/crates/compiler/builtins/roc/Str.roc
@ -34,7 +34,7 @@
 ## ```
 ## name = "Sam"
 ##
-## "Hi, my name is $(name)!"
+## "Hi, my name is ${name}!"
 ## ```
 ##
 ## This will evaluate to the string `"Hi, my name is Sam!"`
@ -44,7 +44,7 @@
 ## ```
 ## colors = ["red", "green", "blue"]
 ##
-## "The colors are $(colors |> Str.join_with(", "))!"
+## "The colors are ${colors |> Str.join_with(", ")}!"
 ## ```
 ##
 ## Interpolation can be used in multiline strings, but the part inside the parentheses must still be on one line.
@ -800,7 +800,7 @@ replace_first : Str, Str, Str -> Str
 replace_first = \haystack, needle, flower ->
    when split_first(haystack, needle) is
        Ok({ before, after }) ->
-            "$(before)$(flower)$(after)"
+            "${before}${flower}${after}"

        Err(NotFound) -> haystack

@ -818,7 +818,7 @@ replace_last : Str, Str, Str -> Str
 replace_last = \haystack, needle, flower ->
    when split_last(haystack, needle) is
        Ok({ before, after }) ->
-            "$(before)$(flower)$(after)"
+            "${before}${flower}${after}"

        Err(NotFound) -> haystack

--- a/crates/compiler/can/tests/test_can.rs
+++ b/crates/compiler/can/tests/test_can.rs
@ -2157,10 +2157,10 @@ mod test_can {
    //         // This should NOT be string interpolation, because of the \\
    //         indoc!(
    //             r#"
-    //                      "abcd\$(efg)hij"
+    //                      "abcd\${efg}hij"
    //                      "#
    //         ),
-    //         Str(r"abcd$(efg)hij".into()),
+    //         Str(r"abcd${efg}hij".into()),
    //     );
    // }

--- a/crates/compiler/fmt/src/expr.rs
+++ b/crates/compiler/fmt/src/expr.rs
@ -91,14 +91,6 @@ fn format_expr_only(
            buf.indent(indent);
            buf.push_str("try");
        }
-        Expr::PncApply(
-            loc_expr @ Loc {
-                value: Expr::Dbg, ..
-            },
-            loc_args,
-        ) => {
-            fmt_apply(loc_expr, loc_args.items, indent, buf);
-        }
        Expr::PncApply(loc_expr, loc_args) => {
            fmt_pnc_apply(loc_expr, loc_args, indent, buf);
        }
@ -521,10 +513,7 @@ pub fn expr_is_multiline(me: &Expr<'_>, comments_only: bool) -> bool {
                    .any(|loc_arg| expr_is_multiline(&loc_arg.value, comments_only))
        }
        Expr::PncApply(loc_expr, args) => {
-            expr_is_multiline(&loc_expr.value, comments_only)
-                || args
-                    .iter()
-                    .any(|loc_arg| expr_is_multiline(&loc_arg.value, comments_only))
+            expr_is_multiline(&loc_expr.value, comments_only) || is_collection_multiline(args)
        }

        Expr::DbgStmt { .. } => true,
@ -922,8 +911,8 @@ fn format_str_segment(seg: &StrSegment, buf: &mut Buf) {
            buf.push(escaped.to_parsed_char());
        }
        Interpolated(loc_expr) => {
-            buf.push_str("$(");
-            // e.g. (name) in "Hi, $(name)!"
+            buf.push_str("${");
+            // e.g. {name} in "Hi, ${name}!"
            let min_indent = buf.cur_line_indent() + INDENT;
            loc_expr.value.format_with_options(
                buf,
@ -932,7 +921,7 @@ fn format_str_segment(seg: &StrSegment, buf: &mut Buf) {
                min_indent,
            );
            buf.indent(min_indent);
-            buf.push(')');
+            buf.push('}');
        }
    }
 }
@ -1343,9 +1332,16 @@ pub fn expr_lift_spaces<'a, 'b: 'a>(

            let right_lifted = expr_lift_spaces_after(Parens::InOperator, arena, &right.value);

+            let mut item =
+                Expr::BinOps(lefts, arena.alloc(Loc::at(right.region, right_lifted.item)));
+
+            if parens == Parens::InApply || parens == Parens::InApplyLastArg {
+                item = Expr::ParensAround(arena.alloc(item));
+            }
+
            Spaces {
                before,
-                item: Expr::BinOps(lefts, arena.alloc(Loc::at(right.region, right_lifted.item))),
+                item,
                after: right_lifted.after,
            }
        }
@ -1759,12 +1755,21 @@ fn fmt_dbg_stmt<'a>(
    args.push(condition);
    args.extend_from_slice(extra_args);

+    if args.is_empty() {
+        Expr::PncApply(&Loc::at_zero(Expr::Dbg), Collection::empty()).format_with_options(
+            buf,
+            parens,
+            Newlines::Yes,
+            indent,
+        );
+    } else {
        Expr::Apply(
            &Loc::at_zero(Expr::Dbg),
            args.into_bump_slice(),
            called_via::CalledVia::Space,
        )
        .format_with_options(buf, parens, Newlines::Yes, indent);
+    }

    let cont_lifted = expr_lift_spaces(Parens::NotNeeded, buf.text.bump(), &continuation.value);

--- a/crates/compiler/fmt/src/pattern.rs
+++ b/crates/compiler/fmt/src/pattern.rs
@ -722,7 +722,7 @@ pub fn pattern_lift_spaces<'a, 'b: 'a>(

            Spaces {
                before: func_lifted.before,
-                item: Pattern::PncApply(arena.alloc(func), *args),
+                item: Pattern::PncApply(arena.alloc(Loc::at_zero(func_lifted.item)), *args),
                after: &[],
            }
        }
--- a/crates/compiler/load/tests/test_reporting.rs
+++ b/crates/compiler/load/tests/test_reporting.rs
@ -5864,7 +5864,7 @@ mod test_reporting {
                r#"
            greeting = "Privet"

-            if Bool.true then 1 else "$(greeting), World!"
+            if Bool.true then 1 else "${greeting}, World!"
            "#,
            ),
            @r#"
@ -5872,7 +5872,7 @@ mod test_reporting {

    This `if` has an `else` branch with a different type from its `then` branch:

-    6│      if Bool.true then 1 else "$(greeting), World!"
+    6│      if Bool.true then 1 else "${greeting}, World!"
                                     ^^^^^^^^^^^^^^^^^^^^^

    The `else` branch is a string of type:
@ -15052,7 +15052,7 @@ All branches in an `if` must have the same type!
            u64_nums = parse_items_with Str.to_u64
            u8_nums = parse_items_with Str.to_u8

-            "$(Inspect.to_str u64_nums) $(Inspect.to_str u8_nums)"
+            "${Inspect.to_str(u64_nums)} ${Inspect.to_str(u8_nums)}"
            "#
        ),
        @"" // no errors
@ -15304,7 +15304,7 @@ All branches in an `if` must have the same type!
            get_cheer = \msg ->
                name = Effect.get_line! {}

-                "$(msg), $(name)!"
+                "${msg}, ${name}!"
            "#
        ),
        @r"
@ -15340,7 +15340,7 @@ All branches in an `if` must have the same type!

            trim : Str -> Str
            trim = \msg ->
-                Effect.put_line! "Trimming $(msg)"
+                Effect.put_line!("Trimming ${msg}")
                Str.trim msg
            "#
        ),
@ -15349,7 +15349,7 @@ All branches in an `if` must have the same type!

    This call to `Effect.put_line!` might produce an effect:

-    10│      Effect.put_line! "Trimming $(msg)"
+    10│      Effect.put_line!("Trimming ${msg}")
             ^^^^^^^^^^^^^^^^

    However, the type of the enclosing function requires that it's pure:
@ -15736,7 +15736,7 @@ All branches in an `if` must have the same type!
                (get, put) = (Effect.get_line!, Effect.put_line!)

                name = get {}
-                put "Hi, $(name)"
+                put "Hi, ${name}"
            "#
        ),
        @r###"
@ -15808,7 +15808,7 @@ All branches in an `if` must have the same type!
                Tag get put = Tag Effect.get_line! Effect.put_line!

                name = get {}
-                put "Hi, $(name)"
+                put "Hi, ${name}"
            "#
        ),
        @r###"
--- a/crates/compiler/load_internal/tests/test_load.rs
+++ b/crates/compiler/load_internal/tests/test_load.rs
@ -1574,7 +1574,7 @@ fn module_params_checks() {
                r#"
            module { key } -> [url]

-            url = "example.com/$(key)"
+            url = "example.com/${key}"
            "#
            ),
        ),
@ -1605,7 +1605,7 @@ fn module_params_optional() {
                r#"
            module { key, exp ? "default" } -> [url]

-            url = "example.com/$(key)?exp=$(exp)"
+            url = "example.com/${key}?exp=${exp}"
            "#
            ),
        ),
@ -1636,7 +1636,7 @@ fn module_params_typecheck_fail() {
                r#"
            module { key } -> [url]

-            url = "example.com/$(key)"
+            url = "example.com/${key}"
            "#
            ),
        ),
@ -1687,7 +1687,7 @@ fn module_params_missing_fields() {
                r#"
            module { key } -> [url]

-            url = "example.com/$(key)"
+            url = "example.com/${key}"
            "#
            ),
        ),
@ -1740,7 +1740,7 @@ fn module_params_extra_fields() {
                r#"
            module { key } -> [url]

-            url = "example.com/$(key)"
+            url = "example.com/${key}"
            "#
            ),
        ),
@ -1839,7 +1839,7 @@ fn module_params_missing() {
                r#"
            module { key, exp } -> [url]

-            url = "example.com/$(key)?exp=$(Num.to_str exp)"
+            url = "example.com/${key}?exp=${Num.to_str(exp)}"
            "#
            ),
        ),
@ -2169,7 +2169,7 @@ fn roc_package_depends_on_other_package() {
                r#"
            module [say]

-            say = \msg -> "$(msg), world!"
+            say = \msg -> "${msg}, world!"
            "#
            ),
        ),
--- a/crates/compiler/module/src/called_via.rs
+++ b/crates/compiler/module/src/called_via.rs
@ -75,7 +75,7 @@ pub enum CalledVia {
    UnaryOp(UnaryOp),

    /// This call is the result of desugaring string interpolation,
-    /// e.g. "$(first) $(last)" is transformed into Str.concat (Str.concat first " ") last.
+    /// e.g. "${first} ${last}" is transformed into `Str.concat(Str.concat(first, " "))` last.
    StringInterpolation,

    /// This call is the result of desugaring a map2-based Record Builder field. e.g.
--- a/crates/compiler/module/src/symbol.rs
+++ b/crates/compiler/module/src/symbol.rs
@ -1515,6 +1515,7 @@ define_builtins! {
        92 LIST_WALK_FX: "walk!"
        93 LIST_SPLIT_ON: "split_on"
        94 LIST_SPLIT_ON_LIST: "split_on_list"
+        95 LIST_WALK_TRY_FX: "walk_try!"
    }
    7 RESULT: "Result" => {
        0 RESULT_RESULT: "Result" exposed_type=true // the Result.Result type alias
--- a/crates/compiler/parse/src/expr.rs
+++ b/crates/compiler/parse/src/expr.rs
@ -242,15 +242,7 @@ fn loc_term<'a>() -> impl Parser<'a, Loc<Expr<'a>>, EExpr<'a>> {
            let mut e = expr;
            let orig_region = e.region;
            for (args_loc, maybe_suffixes) in arg_locs_with_suffixes_vec.iter() {
-                let value = if matches!(
-                    e,
-                    Loc {
-                        value: Expr::Dbg,
-                        ..
-                    }
-                ) {
-                    Expr::Apply(arena.alloc(e), args_loc.value.items, CalledVia::Space)
-                } else if let Some(suffixes) = maybe_suffixes {
+                let value = if let Some(suffixes) = maybe_suffixes {
                    apply_expr_access_chain(
                        arena,
                        Expr::PncApply(arena.alloc(e), args_loc.value),
@ -3150,11 +3142,11 @@ fn stmts_to_defs<'a>(
                        _,
                    ) = e
                    {
-                        let condition = &args[0];
+                        if let Some((first, extra_args)) = args.split_first() {
                            let rest = stmts_to_expr(&stmts[i + 1..], arena)?;
                            let e = Expr::DbgStmt {
-                            first: condition,
-                            extra_args: &args[1..],
+                                first,
+                                extra_args,
                                continuation: arena.alloc(rest),
                            };

@ -3168,6 +3160,14 @@ fn stmts_to_defs<'a>(

                            // don't re-process the rest of the statements; they got consumed by the dbg expr
                            break;
+                        } else {
+                            defs.push_value_def(
+                                ValueDef::Stmt(arena.alloc(Loc::at(sp_stmt.item.region, e))),
+                                sp_stmt.item.region,
+                                sp_stmt.before,
+                                &[],
+                            );
+                        }
                    } else if let Expr::PncApply(
                        Loc {
                            value: Expr::Dbg, ..
@ -3175,11 +3175,11 @@ fn stmts_to_defs<'a>(
                        args,
                    ) = e
                    {
-                        let condition = &args.items[0];
+                        if let Some((first, extra_args)) = args.items.split_first() {
                            let rest = stmts_to_expr(&stmts[i + 1..], arena)?;
                            let e = Expr::DbgStmt {
-                            first: condition,
-                            extra_args: &args.items[1..],
+                                first,
+                                extra_args,
                                continuation: arena.alloc(rest),
                            };

@ -3201,6 +3201,14 @@ fn stmts_to_defs<'a>(
                                &[],
                            );
                        }
+                    } else {
+                        defs.push_value_def(
+                            ValueDef::Stmt(arena.alloc(Loc::at(sp_stmt.item.region, e))),
+                            sp_stmt.item.region,
+                            sp_stmt.before,
+                            &[],
+                        );
+                    }
                } else {
                    let e = if sp_stmt.before.is_empty() {
                        e
--- a/crates/compiler/parse/src/normalize.rs
+++ b/crates/compiler/parse/src/normalize.rs
@ -822,10 +822,11 @@ fn fold_defs<'a>(
                            ),
                        ..
                    }) => {
+                        if let Some((first, extra_args)) = args.split_first() {
                            let rest = fold_defs(arena, defs, final_expr);
                            let new_final = Expr::DbgStmt {
-                            first: args[0],
-                            extra_args: &args[1..],
+                                first,
+                                extra_args,
                                continuation: arena.alloc(Loc::at_zero(rest)),
                            };
                            if new_defs.is_empty() {
@ -835,6 +836,9 @@ fn fold_defs<'a>(
                                arena.alloc(new_defs),
                                arena.alloc(Loc::at_zero(new_final)),
                            );
+                        } else {
+                            new_defs.push_value_def(vd, Region::zero(), &[], &[]);
+                        }
                    }
                    ValueDef::Stmt(&Loc {
                        value:
@ -846,10 +850,11 @@ fn fold_defs<'a>(
                            ),
                        ..
                    }) => {
+                        if let Some((first, extra_args)) = args.items.split_first() {
                            let rest = fold_defs(arena, defs, final_expr);
                            let new_final = Expr::DbgStmt {
-                            first: args.items[0],
-                            extra_args: &args.items[1..],
+                                first,
+                                extra_args,
                                continuation: arena.alloc(Loc::at_zero(rest)),
                            };
                            if new_defs.is_empty() {
@ -859,6 +864,9 @@ fn fold_defs<'a>(
                                arena.alloc(new_defs),
                                arena.alloc(Loc::at_zero(new_final)),
                            );
+                        } else {
+                            new_defs.push_value_def(vd, Region::zero(), &[], &[]);
+                        }
                    }
                    _ => {
                        new_defs.push_value_def(vd, Region::zero(), &[], &[]);
--- a/crates/compiler/parse/src/string_literal.rs
+++ b/crates/compiler/parse/src/string_literal.rs
@ -425,16 +425,18 @@ pub fn parse_str_like_literal<'a>() -> impl Parser<'a, StrLikeLiteral<'a>, EStri
                        }
                    }
                }
-                b'(' if preceded_by_dollar && !is_single_quote => {
+                b'(' | b'{' if preceded_by_dollar && !is_single_quote => {
+                    let old_style_interpolation_block = one_byte == b'(';
+
                    // We're about to begin string interpolation!
                    //
                    // End the previous segment so we can begin a new one.
                    // Retroactively end it right before the `$` char we parsed.
                    // (We can't use end_segment! here because it ends it right after
-                    // the just-parsed character, which here would be '(' rather than '$')
+                    // the just-parsed character, which here would be '{' rather than '$')
                    // Don't push anything if the string would be empty.
                    if segment_parsed_bytes > 2 {
-                        // exclude the 2 chars we just parsed, namely '$' and '('
+                        // exclude the 2 chars we just parsed, namely '$' and '{'
                        let string_bytes = &state.bytes()[0..(segment_parsed_bytes - 2)];

                        match std::str::from_utf8(string_bytes) {
@ -452,19 +454,27 @@ pub fn parse_str_like_literal<'a>() -> impl Parser<'a, StrLikeLiteral<'a>, EStri
                        }
                    }

-                    // Advance past the `$(`
+                    // Advance past the `${`
                    state.advance_mut(2);

                    let original_byte_count = state.bytes().len();

-                    // Parse an arbitrary expression, followed by ')'
+                    // Parse an arbitrary expression, followed by '}' or ')'
+                    let terminating_char = if old_style_interpolation_block {
+                        b')'
+                    } else {
+                        b'}'
+                    };
                    let (_progress, (mut loc_expr, sp), new_state) = and(
                        specialize_err_ref(
                            EString::Format,
                            loc(allocated(reset_min_indent(expr::expr_help())))
                                .trace("str_interpolation"),
                        ),
-                        skip_second(space0_e(EString::FormatEnd), byte(b')', EString::FormatEnd)),
+                        skip_second(
+                            space0_e(EString::FormatEnd),
+                            byte(terminating_char, EString::FormatEnd),
+                        ),
                    )
                    .parse(arena, state, min_indent)?;

@ -488,8 +498,8 @@ pub fn parse_str_like_literal<'a>() -> impl Parser<'a, StrLikeLiteral<'a>, EStri
                }
            }

-            // iff the '$' is followed by '(', this is string interpolation.
-            // We'll check for the '(' on the next iteration of the loop.
+            // iff the '$' is followed by '{', this is string interpolation.
+            // We'll check for the '{' on the next iteration of the loop.
            preceded_by_dollar = one_byte == b'$';
        }

--- a/crates/compiler/parse/tests/test_parse.rs
+++ b/crates/compiler/parse/tests/test_parse.rs
@ -160,17 +160,17 @@ mod test_parse {

    #[test]
    fn escaped_interpolation() {
-        assert_segments(r#""Hi, \$(name)!""#, |arena| {
+        assert_segments(r#""Hi, \${name}!""#, |arena| {
            bumpalo::vec![in arena;
                 Plaintext("Hi, "),
                 EscapedChar(EscapedChar::Dollar),
-                 Plaintext("(name)!"),
+                 Plaintext("{name}!"),
            ]
        });
    }

    #[test]
-    fn string_with_interpolation_in_middle() {
+    fn string_with_old_interpolation_still_works_for_now() {
        assert_segments(r#""Hi, $(name)!""#, |arena| {
            let expr = arena.alloc(Var {
                module_name: "",
@ -185,9 +185,31 @@ mod test_parse {
        });
    }

+    #[test]
+    fn string_with_mixed_new_and_old_interpolation_braces_fails() {
+        assert_parsing_fails(r#""${foo)""#, SyntaxError::Unexpected(Region::zero()));
+        assert_parsing_fails(r#""$(foo}""#, SyntaxError::Unexpected(Region::zero()));
+    }
+
+    #[test]
+    fn string_with_interpolation_in_middle() {
+        assert_segments(r#""Hi, ${name}!""#, |arena| {
+            let expr = arena.alloc(Var {
+                module_name: "",
+                ident: "name",
+            });
+
+            bumpalo::vec![in arena;
+                 Plaintext("Hi, "),
+                 Interpolated(Loc::new(7, 11, expr)),
+                 Plaintext("!")
+            ]
+        });
+    }
+
    #[test]
    fn string_with_interpolation_in_front() {
-        assert_segments(r#""$(name), hi!""#, |arena| {
+        assert_segments(r#""${name}, hi!""#, |arena| {
            let expr = arena.alloc(Var {
                module_name: "",
                ident: "name",
@ -232,7 +254,7 @@ mod test_parse {

    #[test]
    fn string_with_interpolation_in_back() {
-        assert_segments(r#""Hello $(name)""#, |arena| {
+        assert_segments(r#""Hello ${name}""#, |arena| {
            let expr = arena.alloc(Var {
                module_name: "",
                ident: "name",
@ -247,7 +269,7 @@ mod test_parse {

    #[test]
    fn string_with_multiple_interpolations() {
-        assert_segments(r#""Hi, $(name)! How is $(project) going?""#, |arena| {
+        assert_segments(r#""Hi, ${name}! How is ${project} going?""#, |arena| {
            let expr1 = arena.alloc(Var {
                module_name: "",
                ident: "name",
@ -271,7 +293,7 @@ mod test_parse {
    #[test]
    fn string_with_non_interpolation_dollar_signs() {
        assert_segments(
-            r#""$a Hi, $(name)! $b How is $(project) going? $c""#,
+            r#""$a Hi, ${name}! $b How is ${project} going? $c""#,
            |arena| {
                let expr1 = arena.alloc(Var {
                    module_name: "",
--- a/crates/compiler/solve/tests/solve_expr.rs
+++ b/crates/compiler/solve/tests/solve_expr.rs
@ -324,7 +324,7 @@ mod solve_expr {
                r#"
                what_it_is = "great"

-                "type inference is $(what_it_is)!"
+                "type inference is ${what_it_is}!"
            "#
            ),
            "Str",
@ -338,7 +338,7 @@ mod solve_expr {
                r#"
                what_it_is = "great"

-                str = "type inference is $(what_it_is)!"
+                str = "type inference is ${what_it_is}!"

                what_it_is
            "#
@ -354,7 +354,7 @@ mod solve_expr {
                r#"
                rec = { what_it_is: "great" }

-                str = "type inference is $(rec.what_it_is)!"
+                str = "type inference is ${rec.what_it_is}!"

                rec
            "#
@ -4751,7 +4751,7 @@ mod solve_expr {
                r#"
                set_roc_email : _ -> { name: Str, email: Str }_
                set_roc_email = \person ->
-                    { person & email: "$(person.name)@roclang.com" }
+                    { person & email: "${person.name}@roclang.com" }
                set_roc_email
                "#
            ),
--- a/crates/compiler/test_gen/src/gen_list.rs
+++ b/crates/compiler/test_gen/src/gen_list.rs
@ -330,7 +330,7 @@ fn list_map_try_ok() {
            List.map_try [1, 2, 3] \num ->
                str = Num.to_str (num * 2)

-                Ok "$(str)!"
+                Ok "${str}!"
        "#,
        // Result Str [] is unwrapped to just Str
        RocList::<RocStr>::from_slice(&[
@ -3870,10 +3870,10 @@ fn issue_3571_lowlevel_call_function_with_bool_lambda_set() {
                    List.concat state mapped_vals

            add2 : Str -> Str
-            add2 = \x -> "added $(x)"
+            add2 = \x -> "added ${x}"

            mul2 : Str -> Str
-            mul2 = \x -> "multiplied $(x)"
+            mul2 = \x -> "multiplied ${x}"

            foo = [add2, mul2]
            bar = ["1", "2", "3", "4"]
--- a/crates/compiler/test_gen/src/gen_primitives.rs
+++ b/crates/compiler/test_gen/src/gen_primitives.rs
@ -3120,7 +3120,7 @@ fn recursively_build_effect() {
                hi = "Hello"
                name = "World"

-                "$(hi), $(name)!"
+                "${hi}, ${name}!"

            main =
                when nest_help 4 is
@ -3876,8 +3876,8 @@ fn compose_recursive_lambda_set_productive_toplevel() {
            compose = \f, g -> \x -> g (f x)

            identity = \x -> x
-            exclaim = \s -> "$(s)!"
-            whisper = \s -> "($(s))"
+            exclaim = \s -> "${s}!"
+            whisper = \s -> "(${s})"

            main =
                res: Str -> Str
@ -3899,8 +3899,8 @@ fn compose_recursive_lambda_set_productive_nested() {
            compose = \f, g -> \x -> g (f x)

            identity = \x -> x
-            exclaim = \s -> "$(s)!"
-            whisper = \s -> "($(s))"
+            exclaim = \s -> "${s}!"
+            whisper = \s -> "(${s})"

            res: Str -> Str
            res = List.walk [ exclaim, whisper ] identity compose
@ -3921,8 +3921,8 @@ fn compose_recursive_lambda_set_productive_inferred() {
            compose = \f, g -> \x -> g (f x)

            identity = \x -> x
-            exclaim = \s -> "$(s)!"
-            whisper = \s -> "($(s))"
+            exclaim = \s -> "${s}!"
+            whisper = \s -> "(${s})"

            res = List.walk [ exclaim, whisper ] identity compose
            res "hello"
@ -3947,8 +3947,8 @@ fn compose_recursive_lambda_set_productive_nullable_wrapped() {
                else \x -> f (g x)

             identity = \x -> x
-             exclame = \s -> "$(s)!"
-             whisper = \s -> "($(s))"
+             exclame = \s -> "${s}!"
+             whisper = \s -> "(${s})"

             main =
                 res: Str -> Str
@ -4475,7 +4475,7 @@ fn reset_recursive_type_wraps_in_named_type() {
                Cons x xs ->
                  str_x = f x
                  str_xs = print_linked_list xs f
-                  "Cons $(str_x) ($(str_xs))"
+                  "Cons ${str_x} (${str_xs})"
            "#
        ),
        RocStr::from("Cons 2 (Cons 3 (Cons 4 (Nil)))"),
--- a/crates/compiler/test_gen/src/gen_return.rs
+++ b/crates/compiler/test_gen/src/gen_return.rs
@ -37,7 +37,7 @@ fn early_return_nested_ifs() {
                        else
                            third

-                "$(first), $(second)"
+                "${first}, ${second}"

            main : List Str
            main = List.map [1, 2, 3] display_n
@ -76,7 +76,7 @@ fn early_return_nested_whens() {
                                _ ->
                                    third

-                "$(first), $(second)"
+                "${first}, ${second}"

            main : List Str
            main = List.map [1, 2, 3] display_n
--- a/crates/compiler/test_mono/generated/anonymous_closure_in_polymorphic_expression_issue_4717.txt
+++ b/crates/compiler/test_mono/generated/anonymous_closure_in_polymorphic_expression_issue_4717.txt
@ -2,81 +2,81 @@ procedure Bool.11 (#Attr.2, #Attr.3):
    let Bool.23 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
    ret Bool.23;

-procedure List.115 (List.562, List.563, List.564):
-    let List.683 : U64 = 0i64;
-    let List.684 : U64 = CallByName List.6 List.562;
-    let List.682 : [C U64, C U64] = CallByName List.80 List.562 List.563 List.564 List.683 List.684;
-    ret List.682;
+procedure List.116 (List.563, List.564, List.565):
+    let List.693 : U64 = 0i64;
+    let List.694 : U64 = CallByName List.6 List.563;
+    let List.692 : [C U64, C U64] = CallByName List.80 List.563 List.564 List.565 List.693 List.694;
+    ret List.692;

-procedure List.26 (List.212, List.213, List.214):
-    let List.676 : [C U64, C U64] = CallByName List.115 List.212 List.213 List.214;
-    let List.679 : U8 = 1i64;
-    let List.680 : U8 = GetTagId List.676;
-    let List.681 : Int1 = lowlevel Eq List.679 List.680;
-    if List.681 then
-        let List.215 : U64 = UnionAtIndex (Id 1) (Index 0) List.676;
-        ret List.215;
-    else
-        let List.216 : U64 = UnionAtIndex (Id 0) (Index 0) List.676;
+procedure List.26 (List.213, List.214, List.215):
+    let List.686 : [C U64, C U64] = CallByName List.116 List.213 List.214 List.215;
+    let List.689 : U8 = 1i64;
+    let List.690 : U8 = GetTagId List.686;
+    let List.691 : Int1 = lowlevel Eq List.689 List.690;
+    if List.691 then
+        let List.216 : U64 = UnionAtIndex (Id 1) (Index 0) List.686;
        ret List.216;
+    else
+        let List.217 : U64 = UnionAtIndex (Id 0) (Index 0) List.686;
+        ret List.217;

-procedure List.38 (List.400, List.401):
-    let List.675 : U64 = CallByName List.6 List.400;
-    let List.402 : U64 = CallByName Num.77 List.675 List.401;
-    let List.665 : List U8 = CallByName List.43 List.400 List.402;
-    ret List.665;
+procedure List.38 (List.401, List.402):
+    let List.685 : U64 = CallByName List.6 List.401;
+    let List.403 : U64 = CallByName Num.77 List.685 List.402;
+    let List.675 : List U8 = CallByName List.43 List.401 List.403;
+    ret List.675;

-procedure List.43 (List.398, List.399):
-    let List.673 : U64 = CallByName List.6 List.398;
-    let List.672 : U64 = CallByName Num.77 List.673 List.399;
-    let List.667 : {U64, U64} = Struct {List.399, List.672};
-    let List.666 : List U8 = CallByName List.49 List.398 List.667;
-    ret List.666;
+procedure List.43 (List.399, List.400):
+    let List.683 : U64 = CallByName List.6 List.399;
+    let List.682 : U64 = CallByName Num.77 List.683 List.400;
+    let List.677 : {U64, U64} = Struct {List.400, List.682};
+    let List.676 : List U8 = CallByName List.49 List.399 List.677;
+    ret List.676;

-procedure List.49 (List.476, List.477):
-    let List.669 : U64 = StructAtIndex 1 List.477;
-    let List.670 : U64 = StructAtIndex 0 List.477;
-    let List.668 : List U8 = CallByName List.72 List.476 List.669 List.670;
-    ret List.668;
+procedure List.49 (List.477, List.478):
+    let List.679 : U64 = StructAtIndex 1 List.478;
+    let List.680 : U64 = StructAtIndex 0 List.478;
+    let List.678 : List U8 = CallByName List.72 List.477 List.679 List.680;
+    ret List.678;

 procedure List.6 (#Attr.2):
-    let List.674 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.674;
+    let List.684 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.684;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.697 : U8 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.697;
+    let List.707 : U8 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.707;

 procedure List.72 (#Attr.2, #Attr.3, #Attr.4):
-    let List.671 : List U8 = lowlevel ListSublist #Attr.2 #Attr.3 #Attr.4;
-    ret List.671;
+    let List.681 : List U8 = lowlevel ListSublist #Attr.2 #Attr.3 #Attr.4;
+    ret List.681;

 procedure List.80 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.685 List.565 List.566 List.567 List.568 List.569:
-        let List.687 : Int1 = CallByName Num.22 List.568 List.569;
-        if List.687 then
-            let List.696 : U8 = CallByName List.66 List.565 List.568;
-            let List.688 : [C U64, C U64] = CallByName Test.4 List.566 List.696;
-            let List.693 : U8 = 1i64;
-            let List.694 : U8 = GetTagId List.688;
-            let List.695 : Int1 = lowlevel Eq List.693 List.694;
-            if List.695 then
-                let List.570 : U64 = UnionAtIndex (Id 1) (Index 0) List.688;
-                let List.691 : U64 = 1i64;
-                let List.690 : U64 = CallByName Num.51 List.568 List.691;
-                jump List.685 List.565 List.570 List.567 List.690 List.569;
+    joinpoint List.695 List.566 List.567 List.568 List.569 List.570:
+        let List.697 : Int1 = CallByName Num.22 List.569 List.570;
+        if List.697 then
+            let List.706 : U8 = CallByName List.66 List.566 List.569;
+            let List.698 : [C U64, C U64] = CallByName Test.4 List.567 List.706;
+            let List.703 : U8 = 1i64;
+            let List.704 : U8 = GetTagId List.698;
+            let List.705 : Int1 = lowlevel Eq List.703 List.704;
+            if List.705 then
+                let List.571 : U64 = UnionAtIndex (Id 1) (Index 0) List.698;
+                let List.701 : U64 = 1i64;
+                let List.700 : U64 = CallByName Num.51 List.569 List.701;
+                jump List.695 List.566 List.571 List.568 List.700 List.570;
            else
-                dec List.565;
-                let List.571 : U64 = UnionAtIndex (Id 0) (Index 0) List.688;
-                let List.692 : [C U64, C U64] = TagId(0) List.571;
-                ret List.692;
+                dec List.566;
+                let List.572 : U64 = UnionAtIndex (Id 0) (Index 0) List.698;
+                let List.702 : [C U64, C U64] = TagId(0) List.572;
+                ret List.702;
        else
-            dec List.565;
-            let List.686 : [C U64, C U64] = TagId(1) List.566;
-            ret List.686;
+            dec List.566;
+            let List.696 : [C U64, C U64] = TagId(1) List.567;
+            ret List.696;
    in
    inc #Derived_gen.0;
-    jump List.685 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    jump List.695 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.286 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/call_function_in_empty_list.txt
+++ b/crates/compiler/test_mono/generated/call_function_in_empty_list.txt
@ -1,51 +1,51 @@
-procedure List.100 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.671 List.174 List.175 List.176 List.177 List.178:
-        let List.673 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.673 then
-            let List.677 : [] = CallByName List.66 List.174 List.177;
-            let List.179 : List {} = CallByName List.283 List.175 List.677 List.176;
-            let List.676 : U64 = 1i64;
-            let List.675 : U64 = CallByName Num.51 List.177 List.676;
-            jump List.671 List.174 List.179 List.176 List.675 List.178;
+procedure List.101 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
+    joinpoint List.681 List.175 List.176 List.177 List.178 List.179:
+        let List.683 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.683 then
+            let List.687 : [] = CallByName List.66 List.175 List.178;
+            let List.180 : List {} = CallByName List.284 List.176 List.687 List.177;
+            let List.686 : U64 = 1i64;
+            let List.685 : U64 = CallByName Num.51 List.178 List.686;
+            jump List.681 List.175 List.180 List.177 List.685 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.0;
-    jump List.671 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    jump List.681 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

-procedure List.18 (List.171, List.172, List.173):
-    let List.669 : U64 = 0i64;
-    let List.670 : U64 = CallByName List.6 List.171;
-    let List.668 : List {} = CallByName List.100 List.171 List.172 List.173 List.669 List.670;
-    ret List.668;
-
-procedure List.283 (List.284, List.285, List.281):
-    let List.682 : {} = CallByName Test.2 List.285;
-    let List.681 : List {} = CallByName List.71 List.284 List.682;
-    ret List.681;
-
-procedure List.5 (List.280, List.281):
-    let List.282 : U64 = CallByName List.6 List.280;
-    let List.666 : List {} = CallByName List.68 List.282;
-    let List.665 : List {} = CallByName List.18 List.280 List.666 List.281;
-    ret List.665;
-
-procedure List.6 (#Attr.2):
-    let List.679 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.679;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.678 : [] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.679 : U64 = 0i64;
+    let List.680 : U64 = CallByName List.6 List.172;
+    let List.678 : List {} = CallByName List.101 List.172 List.173 List.174 List.679 List.680;
    ret List.678;

+procedure List.284 (List.285, List.286, List.282):
+    let List.692 : {} = CallByName Test.2 List.286;
+    let List.691 : List {} = CallByName List.71 List.285 List.692;
+    ret List.691;
+
+procedure List.5 (List.281, List.282):
+    let List.283 : U64 = CallByName List.6 List.281;
+    let List.676 : List {} = CallByName List.68 List.283;
+    let List.675 : List {} = CallByName List.18 List.281 List.676 List.282;
+    ret List.675;
+
+procedure List.6 (#Attr.2):
+    let List.689 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.689;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.688 : [] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.688;
+
 procedure List.68 (#Attr.2):
-    let List.684 : List {} = lowlevel ListWithCapacity #Attr.2;
-    ret List.684;
+    let List.694 : List {} = lowlevel ListWithCapacity #Attr.2;
+    ret List.694;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.683 : List {} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.683;
+    let List.693 : List {} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.693;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- 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
@ -1,51 +1,51 @@
-procedure List.100 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.671 List.174 List.175 List.176 List.177 List.178:
-        let List.673 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.673 then
-            let List.677 : [] = CallByName List.66 List.174 List.177;
-            let List.179 : List [] = CallByName List.283 List.175 List.677 List.176;
-            let List.676 : U64 = 1i64;
-            let List.675 : U64 = CallByName Num.51 List.177 List.676;
-            jump List.671 List.174 List.179 List.176 List.675 List.178;
+procedure List.101 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
+    joinpoint List.681 List.175 List.176 List.177 List.178 List.179:
+        let List.683 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.683 then
+            let List.687 : [] = CallByName List.66 List.175 List.178;
+            let List.180 : List [] = CallByName List.284 List.176 List.687 List.177;
+            let List.686 : U64 = 1i64;
+            let List.685 : U64 = CallByName Num.51 List.178 List.686;
+            jump List.681 List.175 List.180 List.177 List.685 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.0;
-    jump List.671 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    jump List.681 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

-procedure List.18 (List.171, List.172, List.173):
-    let List.669 : U64 = 0i64;
-    let List.670 : U64 = CallByName List.6 List.171;
-    let List.668 : List [] = CallByName List.100 List.171 List.172 List.173 List.669 List.670;
-    ret List.668;
-
-procedure List.283 (List.284, List.285, List.281):
-    let List.682 : [] = CallByName Test.2 List.285;
-    let List.681 : List [] = CallByName List.71 List.284 List.682;
-    ret List.681;
-
-procedure List.5 (List.280, List.281):
-    let List.282 : U64 = CallByName List.6 List.280;
-    let List.666 : List [] = CallByName List.68 List.282;
-    let List.665 : List [] = CallByName List.18 List.280 List.666 List.281;
-    ret List.665;
-
-procedure List.6 (#Attr.2):
-    let List.679 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.679;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.678 : [] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.679 : U64 = 0i64;
+    let List.680 : U64 = CallByName List.6 List.172;
+    let List.678 : List [] = CallByName List.101 List.172 List.173 List.174 List.679 List.680;
    ret List.678;

+procedure List.284 (List.285, List.286, List.282):
+    let List.692 : [] = CallByName Test.2 List.286;
+    let List.691 : List [] = CallByName List.71 List.285 List.692;
+    ret List.691;
+
+procedure List.5 (List.281, List.282):
+    let List.283 : U64 = CallByName List.6 List.281;
+    let List.676 : List [] = CallByName List.68 List.283;
+    let List.675 : List [] = CallByName List.18 List.281 List.676 List.282;
+    ret List.675;
+
+procedure List.6 (#Attr.2):
+    let List.689 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.689;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.688 : [] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.688;
+
 procedure List.68 (#Attr.2):
-    let List.684 : List [] = lowlevel ListWithCapacity #Attr.2;
-    ret List.684;
+    let List.694 : List [] = lowlevel ListWithCapacity #Attr.2;
+    ret List.694;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.683 : List [] = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.683;
+    let List.693 : List [] = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.693;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/capture_void_layout_task.txt
+++ b/crates/compiler/test_mono/generated/capture_void_layout_task.txt
@ -1,32 +1,32 @@
-procedure List.100 (#Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14, #Derived_gen.15):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : [] = CallByName List.66 List.174 List.177;
-            let List.179 : [<r>C {}, C *self {{}, []}] = CallByName Test.29 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.8, #Derived_gen.9, #Derived_gen.10, #Derived_gen.11, #Derived_gen.12):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : [] = CallByName List.66 List.175 List.178;
+            let List.180 : [<r>C {}, C *self {{}, []}] = CallByName Test.29 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.11;
-    jump List.668 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14 #Derived_gen.15;
+    inc #Derived_gen.8;
+    jump List.678 #Derived_gen.8 #Derived_gen.9 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : [<r>C {}, C *self {{}, []}] = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : [<r>C {}, C *self {{}, []}] = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : [] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : [] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- 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.665 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.665;
+    let List.675 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.675;

 procedure Test.1 (Test.5):
    let Test.2 : I64 = 41i64;
--- a/crates/compiler/test_mono/generated/compose_recursive_lambda_set_productive_nullable_wrapped.txt
+++ b/crates/compiler/test_mono/generated/compose_recursive_lambda_set_productive_nullable_wrapped.txt
@ -2,35 +2,35 @@ procedure Bool.2 ():
    let Bool.23 : Int1 = true;
    ret Bool.23;

-procedure List.100 (#Derived_gen.3, #Derived_gen.4, #Derived_gen.5, #Derived_gen.6, #Derived_gen.7):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : Int1 = CallByName List.66 List.174 List.177;
-            let List.179 : [<rnw><null>, C *self Int1, C *self Int1] = CallByName Test.6 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.5, #Derived_gen.6, #Derived_gen.7, #Derived_gen.8, #Derived_gen.9):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : Int1 = CallByName List.66 List.175 List.178;
+            let List.180 : [<rnw><null>, C *self Int1, C *self Int1] = CallByName Test.6 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.3;
-    jump List.668 #Derived_gen.3 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7;
+    inc #Derived_gen.5;
+    jump List.678 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7 #Derived_gen.8 #Derived_gen.9;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : [<rnw><null>, C *self Int1, C *self Int1] = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : [<rnw><null>, C *self Int1, C *self Int1] = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : Int1 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : Int1 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/dict.txt
+++ b/crates/compiler/test_mono/generated/dict.txt
@ -26,8 +26,8 @@ procedure Dict.52 ():
    ret Dict.744;

 procedure List.6 (#Attr.2):
-    let List.665 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.665;
+    let List.675 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.675;

 procedure Num.75 (#Attr.2, #Attr.3):
    let Num.283 : U8 = lowlevel NumSubWrap #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/empty_list_of_function_type.txt
+++ b/crates/compiler/test_mono/generated/empty_list_of_function_type.txt
@ -2,25 +2,25 @@ procedure Bool.1 ():
    let Bool.23 : Int1 = false;
    ret Bool.23;

-procedure List.2 (List.119, List.120):
-    let List.671 : U64 = CallByName List.6 List.119;
-    let List.667 : Int1 = CallByName Num.22 List.120 List.671;
-    if List.667 then
-        let List.669 : {} = CallByName List.66 List.119 List.120;
-        let List.668 : [C {}, C {}] = TagId(1) List.669;
-        ret List.668;
+procedure List.2 (List.120, List.121):
+    let List.681 : U64 = CallByName List.6 List.120;
+    let List.677 : Int1 = CallByName Num.22 List.121 List.681;
+    if List.677 then
+        let List.679 : {} = CallByName List.66 List.120 List.121;
+        let List.678 : [C {}, C {}] = TagId(1) List.679;
+        ret List.678;
    else
-        let List.666 : {} = Struct {};
-        let List.665 : [C {}, C {}] = TagId(0) List.666;
-        ret List.665;
+        let List.676 : {} = Struct {};
+        let List.675 : [C {}, C {}] = TagId(0) List.676;
+        ret List.675;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.670 : {} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.670;
+    let List.680 : {} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.680;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.283 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/encode.txt
+++ b/crates/compiler/test_mono/generated/encode.txt
@ -1,16 +1,16 @@
-procedure List.4 (List.135, List.136):
-    let List.668 : U64 = 1i64;
-    let List.666 : List U8 = CallByName List.70 List.135 List.668;
-    let List.665 : List U8 = CallByName List.71 List.666 List.136;
-    ret List.665;
+procedure List.4 (List.136, List.137):
+    let List.678 : U64 = 1i64;
+    let List.676 : List U8 = CallByName List.70 List.136 List.678;
+    let List.675 : List U8 = CallByName List.71 List.676 List.137;
+    ret List.675;

 procedure List.70 (#Attr.2, #Attr.3):
-    let List.669 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.669;
+    let List.679 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.679;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.667 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.667;
+    let List.677 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.677;

 procedure Test.23 (Test.24, Test.35, Test.22):
    let Test.37 : List U8 = CallByName List.4 Test.24 Test.22;
--- a/crates/compiler/test_mono/generated/encode_derived_nested_record_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_nested_record_string.txt
@ -67,85 +67,85 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.26, #Derived_gen.27, #Derived_gen.28, #Derived_gen.29, #Derived_gen.30):
-    joinpoint List.694 List.174 List.175 List.176 List.177 List.178:
-        let List.696 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.696 then
-            let List.700 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.700;
-            let List.179 : List U8 = CallByName Test.71 List.175 List.700;
-            let List.699 : U64 = 1i64;
-            let List.698 : U64 = CallByName Num.51 List.177 List.699;
-            jump List.694 List.174 List.179 List.176 List.698 List.178;
+procedure List.101 (#Derived_gen.26, #Derived_gen.27, #Derived_gen.28, #Derived_gen.29, #Derived_gen.30):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.71 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.26;
-    jump List.694 #Derived_gen.26 #Derived_gen.27 #Derived_gen.28 #Derived_gen.29 #Derived_gen.30;
+    jump List.678 #Derived_gen.26 #Derived_gen.27 #Derived_gen.28 #Derived_gen.29 #Derived_gen.30;

-procedure List.100 (#Derived_gen.34, #Derived_gen.35, #Derived_gen.36, #Derived_gen.37, #Derived_gen.38):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.71 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.31, #Derived_gen.32, #Derived_gen.33, #Derived_gen.34, #Derived_gen.35):
+    joinpoint List.704 List.175 List.176 List.177 List.178 List.179:
+        let List.706 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.706 then
+            let List.710 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.710;
+            let List.180 : List U8 = CallByName Test.71 List.176 List.710;
+            let List.709 : U64 = 1i64;
+            let List.708 : U64 = CallByName Num.51 List.178 List.709;
+            jump List.704 List.175 List.180 List.177 List.708 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.34;
-    jump List.668 #Derived_gen.34 #Derived_gen.35 #Derived_gen.36 #Derived_gen.37 #Derived_gen.38;
+    inc #Derived_gen.31;
+    jump List.704 #Derived_gen.31 #Derived_gen.32 #Derived_gen.33 #Derived_gen.34 #Derived_gen.35;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.18 (List.171, List.172, List.173):
-    let List.692 : U64 = 0i64;
-    let List.693 : U64 = CallByName List.6 List.171;
-    let List.691 : List U8 = CallByName List.100 List.171 List.172 List.173 List.692 List.693;
-    ret List.691;
-
-procedure List.4 (List.135, List.136):
-    let List.713 : U64 = 1i64;
-    let List.712 : List U8 = CallByName List.70 List.135 List.713;
-    let List.711 : List U8 = CallByName List.71 List.712 List.136;
-    ret List.711;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.6 (#Attr.2):
-    let List.716 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.716;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

-procedure List.66 (#Attr.2, #Attr.3):
-    let List.701 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.702 : U64 = 0i64;
+    let List.703 : U64 = CallByName List.6 List.172;
+    let List.701 : List U8 = CallByName List.101 List.172 List.173 List.174 List.702 List.703;
    ret List.701;

+procedure List.4 (List.136, List.137):
+    let List.723 : U64 = 1i64;
+    let List.722 : List U8 = CallByName List.70 List.136 List.723;
+    let List.721 : List U8 = CallByName List.71 List.722 List.137;
+    ret List.721;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.6 (#Attr.2):
+    let List.726 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.726;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.711 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.711;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.707 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.707;
+    let List.717 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.717;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.705 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.705;
+    let List.715 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.715;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.715 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.715;
+    let List.725 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.725;

 procedure Num.127 (#Attr.2):
    let Num.288 : U8 = lowlevel NumIntCast #Attr.2;
--- 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
@ -39,54 +39,54 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.16, #Derived_gen.17, #Derived_gen.18, #Derived_gen.19, #Derived_gen.20):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.71 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.16, #Derived_gen.17, #Derived_gen.18, #Derived_gen.19, #Derived_gen.20):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.71 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.16;
-    jump List.668 #Derived_gen.16 #Derived_gen.17 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20;
+    jump List.678 #Derived_gen.16 #Derived_gen.17 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.4 (List.135, List.136):
-    let List.687 : U64 = 1i64;
-    let List.686 : List U8 = CallByName List.70 List.135 List.687;
-    let List.685 : List U8 = CallByName List.71 List.686 List.136;
-    ret List.685;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

+procedure List.4 (List.136, List.137):
+    let List.697 : U64 = 1i64;
+    let List.696 : List U8 = CallByName List.70 List.136 List.697;
+    let List.695 : List U8 = CallByName List.71 List.696 List.137;
+    ret List.695;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.681 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.681;
+    let List.691 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.691;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.679 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.679;
+    let List.689 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.689;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.689 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.127 (#Attr.2):
    let Num.284 : U8 = lowlevel NumIntCast #Attr.2;
--- 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
@ -46,54 +46,54 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.71 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.71 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.20;
-    jump List.668 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;
+    jump List.678 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.4 (List.135, List.136):
-    let List.687 : U64 = 1i64;
-    let List.686 : List U8 = CallByName List.70 List.135 List.687;
-    let List.685 : List U8 = CallByName List.71 List.686 List.136;
-    ret List.685;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

+procedure List.4 (List.136, List.137):
+    let List.697 : U64 = 1i64;
+    let List.696 : List U8 = CallByName List.70 List.136 List.697;
+    let List.695 : List U8 = CallByName List.71 List.696 List.137;
+    ret List.695;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.681 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.681;
+    let List.691 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.691;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.679 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.679;
+    let List.689 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.689;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.689 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.127 (#Attr.2):
    let Num.284 : U8 = lowlevel NumIntCast #Attr.2;
--- a/crates/compiler/test_mono/generated/encode_derived_string.txt
+++ b/crates/compiler/test_mono/generated/encode_derived_string.txt
@ -11,23 +11,23 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.4 (List.135, List.136):
-    let List.675 : U64 = 1i64;
-    let List.674 : List U8 = CallByName List.70 List.135 List.675;
-    let List.673 : List U8 = CallByName List.71 List.674 List.136;
-    ret List.673;
+procedure List.4 (List.136, List.137):
+    let List.685 : U64 = 1i64;
+    let List.684 : List U8 = CallByName List.70 List.136 List.685;
+    let List.683 : List U8 = CallByName List.71 List.684 List.137;
+    ret List.683;

 procedure List.70 (#Attr.2, #Attr.3):
-    let List.669 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.669;
+    let List.679 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.679;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.667 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.667;
+    let List.677 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.677;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.677 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.677;
+    let List.687 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.687;

 procedure Num.127 (#Attr.2):
    let Num.284 : U8 = lowlevel NumIntCast #Attr.2;
--- 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
@ -40,58 +40,58 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.10, #Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : Str = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.64 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.10, #Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : Str = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.64 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.10;
-    jump List.668 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14;
+    jump List.678 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14;

 procedure List.13 (#Attr.2, #Attr.3):
-    let List.691 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
-    ret List.691;
+    let List.701 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
+    ret List.701;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.4 (List.135, List.136):
-    let List.687 : U64 = 1i64;
-    let List.686 : List U8 = CallByName List.70 List.135 List.687;
-    let List.685 : List U8 = CallByName List.71 List.686 List.136;
-    ret List.685;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

+procedure List.4 (List.136, List.137):
+    let List.697 : U64 = 1i64;
+    let List.696 : List U8 = CallByName List.70 List.136 List.697;
+    let List.695 : List U8 = CallByName List.71 List.696 List.137;
+    ret List.695;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.681 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.681;
+    let List.691 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.691;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.679 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.679;
+    let List.689 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.689;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.689 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.127 (#Attr.2):
    let Num.284 : U8 = lowlevel NumIntCast #Attr.2;
--- 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
@ -43,58 +43,58 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : Str = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.64 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : Str = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.64 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.20;
-    jump List.668 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;
+    jump List.678 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;

 procedure List.13 (#Attr.2, #Attr.3):
-    let List.691 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
-    ret List.691;
+    let List.701 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
+    ret List.701;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.4 (List.135, List.136):
-    let List.687 : U64 = 1i64;
-    let List.686 : List U8 = CallByName List.70 List.135 List.687;
-    let List.685 : List U8 = CallByName List.71 List.686 List.136;
-    ret List.685;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

+procedure List.4 (List.136, List.137):
+    let List.697 : U64 = 1i64;
+    let List.696 : List U8 = CallByName List.70 List.136 List.697;
+    let List.695 : List U8 = CallByName List.71 List.696 List.137;
+    ret List.695;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.681 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.681;
+    let List.691 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.691;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.679 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.679;
+    let List.689 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.689;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.689 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.127 (#Attr.2):
    let Num.284 : U8 = lowlevel NumIntCast #Attr.2;
--- a/crates/compiler/test_mono/generated/inspect_derived_dict.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_dict.txt
@ -312,7 +312,7 @@ procedure Dict.72 (Dict.413, Dict.414, Dict.415):
    let Dict.855 : {U64, U32} = CallByName Dict.73 Dict.413 Dict.418 Dict.417;
    ret Dict.855;

-procedure Dict.73 (#Derived_gen.10, #Derived_gen.11, #Derived_gen.12):
+procedure Dict.73 (#Derived_gen.15, #Derived_gen.16, #Derived_gen.17):
    joinpoint Dict.856 Dict.419 Dict.420 Dict.421:
        let Dict.422 : {U32, U32} = CallByName Dict.22 Dict.419 Dict.420;
        let Dict.863 : U32 = StructAtIndex 1 Dict.422;
@ -327,8 +327,8 @@ procedure Dict.73 (#Derived_gen.10, #Derived_gen.11, #Derived_gen.12):
            let Dict.857 : {U64, U32} = Struct {Dict.420, Dict.421};
            ret Dict.857;
    in
-    inc #Derived_gen.10;
-    jump Dict.856 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12;
+    inc #Derived_gen.15;
+    jump Dict.856 #Derived_gen.15 #Derived_gen.16 #Derived_gen.17;

 procedure Dict.74 (#Derived_gen.48, #Derived_gen.49, #Derived_gen.50):
    joinpoint Dict.762 Dict.423 Dict.424 Dict.425:
@ -902,171 +902,171 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.100 (#Derived_gen.34, #Derived_gen.35, #Derived_gen.36, #Derived_gen.37, #Derived_gen.38):
-    joinpoint List.732 List.174 List.175 List.176 List.177 List.178:
-        let List.734 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.734 then
-            let List.738 : {Str, I64} = CallByName List.66 List.174 List.177;
-            inc List.738;
-            let List.179 : {Str, Int1} = CallByName Dict.188 List.175 List.738 List.176;
-            let List.737 : U64 = 1i64;
-            let List.736 : U64 = CallByName Num.51 List.177 List.737;
-            jump List.732 List.174 List.179 List.176 List.736 List.178;
+procedure List.101 (#Derived_gen.10, #Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, I64} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : {List {U32, U32}, List {Str, I64}, U64, Float32, U8} = CallByName Dict.159 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.34;
-    jump List.732 #Derived_gen.34 #Derived_gen.35 #Derived_gen.36 #Derived_gen.37 #Derived_gen.38;
+    inc #Derived_gen.10;
+    jump List.678 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14;

-procedure List.100 (#Derived_gen.60, #Derived_gen.61, #Derived_gen.62, #Derived_gen.63, #Derived_gen.64):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, I64} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : {List {U32, U32}, List {Str, I64}, U64, Float32, U8} = CallByName Dict.159 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.51, #Derived_gen.52, #Derived_gen.53, #Derived_gen.54, #Derived_gen.55):
+    joinpoint List.742 List.175 List.176 List.177 List.178 List.179:
+        let List.744 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.744 then
+            let List.748 : {Str, I64} = CallByName List.66 List.175 List.178;
+            inc List.748;
+            let List.180 : {Str, Int1} = CallByName Dict.188 List.176 List.748 List.177;
+            let List.747 : U64 = 1i64;
+            let List.746 : U64 = CallByName Num.51 List.178 List.747;
+            jump List.742 List.175 List.180 List.177 List.746 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.60;
-    jump List.668 #Derived_gen.60 #Derived_gen.61 #Derived_gen.62 #Derived_gen.63 #Derived_gen.64;
+    inc #Derived_gen.51;
+    jump List.742 #Derived_gen.51 #Derived_gen.52 #Derived_gen.53 #Derived_gen.54 #Derived_gen.55;

-procedure List.101 (#Derived_gen.15, #Derived_gen.16, #Derived_gen.17, #Derived_gen.18, #Derived_gen.19):
-    joinpoint List.707 List.183 List.184 List.185 List.186 List.187:
-        let List.709 : Int1 = CallByName Num.22 List.186 List.187;
-        if List.709 then
-            let List.713 : {Str, I64} = CallByName List.66 List.183 List.186;
-            inc List.713;
-            let List.188 : List {U32, U32} = CallByName Dict.407 List.184 List.713 List.186 List.185;
-            let List.712 : U64 = 1i64;
-            let List.711 : U64 = CallByName Num.51 List.186 List.712;
-            jump List.707 List.183 List.188 List.185 List.711 List.187;
+procedure List.102 (#Derived_gen.23, #Derived_gen.24, #Derived_gen.25, #Derived_gen.26, #Derived_gen.27):
+    joinpoint List.717 List.184 List.185 List.186 List.187 List.188:
+        let List.719 : Int1 = CallByName Num.22 List.187 List.188;
+        if List.719 then
+            let List.723 : {Str, I64} = CallByName List.66 List.184 List.187;
+            inc List.723;
+            let List.189 : List {U32, U32} = CallByName Dict.407 List.185 List.723 List.187 List.186;
+            let List.722 : U64 = 1i64;
+            let List.721 : U64 = CallByName Num.51 List.187 List.722;
+            jump List.717 List.184 List.189 List.186 List.721 List.188;
        else
-            dec List.183;
-            ret List.184;
+            dec List.184;
+            ret List.185;
    in
-    inc #Derived_gen.15;
-    jump List.707 #Derived_gen.15 #Derived_gen.16 #Derived_gen.17 #Derived_gen.18 #Derived_gen.19;
+    inc #Derived_gen.23;
+    jump List.717 #Derived_gen.23 #Derived_gen.24 #Derived_gen.25 #Derived_gen.26 #Derived_gen.27;

-procedure List.11 (List.149, List.150):
-    let List.727 : List {U32, U32} = CallByName List.68 List.150;
-    let List.726 : List {U32, U32} = CallByName List.98 List.149 List.150 List.727;
-    ret List.726;
+procedure List.11 (List.150, List.151):
+    let List.737 : List {U32, U32} = CallByName List.68 List.151;
+    let List.736 : List {U32, U32} = CallByName List.99 List.150 List.151 List.737;
+    ret List.736;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : {List {U32, U32}, List {Str, I64}, U64, Float32, U8} = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : {List {U32, U32}, List {Str, I64}, U64, Float32, U8} = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

-procedure List.18 (List.171, List.172, List.173):
-    let List.730 : U64 = 0i64;
-    let List.731 : U64 = CallByName List.6 List.171;
-    let List.729 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.730 List.731;
-    ret List.729;
-
-procedure List.3 (List.127, List.128, List.129):
-    let List.691 : {List {U32, U32}, {U32, U32}} = CallByName List.64 List.127 List.128 List.129;
-    let List.690 : List {U32, U32} = StructAtIndex 0 List.691;
-    ret List.690;
-
-procedure List.3 (List.127, List.128, List.129):
-    let List.693 : {List {Str, I64}, {Str, I64}} = CallByName List.64 List.127 List.128 List.129;
-    let List.692 : List {Str, I64} = StructAtIndex 0 List.693;
-    let #Derived_gen.74 : {Str, I64} = StructAtIndex 1 List.693;
-    dec #Derived_gen.74;
-    ret List.692;
-
-procedure List.4 (List.135, List.136):
-    let List.702 : U64 = 1i64;
-    let List.700 : List {Str, I64} = CallByName List.70 List.135 List.702;
-    let List.699 : List {Str, I64} = CallByName List.71 List.700 List.136;
-    ret List.699;
-
-procedure List.6 (#Attr.2):
-    let List.681 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.681;
-
-procedure List.6 (#Attr.2):
-    let List.728 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.728;
-
-procedure List.6 (#Attr.2):
-    let List.740 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.740;
-
-procedure List.64 (List.124, List.125, List.126):
-    let List.689 : U64 = CallByName List.6 List.124;
-    let List.686 : Int1 = CallByName Num.22 List.125 List.689;
-    if List.686 then
-        let List.687 : {List {U32, U32}, {U32, U32}} = CallByName List.67 List.124 List.125 List.126;
-        ret List.687;
-    else
-        let List.685 : {List {U32, U32}, {U32, U32}} = Struct {List.124, List.126};
-        ret List.685;
-
-procedure List.64 (List.124, List.125, List.126):
-    let List.698 : U64 = CallByName List.6 List.124;
-    let List.695 : Int1 = CallByName Num.22 List.125 List.698;
-    if List.695 then
-        let List.696 : {List {Str, I64}, {Str, I64}} = CallByName List.67 List.124 List.125 List.126;
-        ret List.696;
-    else
-        let List.694 : {List {Str, I64}, {Str, I64}} = Struct {List.124, List.126};
-        ret List.694;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.739 : {Str, I64} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.740 : U64 = 0i64;
+    let List.741 : U64 = CallByName List.6 List.172;
+    let List.739 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.740 List.741;
    ret List.739;

-procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.688 : {List {U32, U32}, {U32, U32}} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.688;
+procedure List.3 (List.128, List.129, List.130):
+    let List.701 : {List {U32, U32}, {U32, U32}} = CallByName List.64 List.128 List.129 List.130;
+    let List.700 : List {U32, U32} = StructAtIndex 0 List.701;
+    ret List.700;

-procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.697 : {List {Str, I64}, {Str, I64}} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+procedure List.3 (List.128, List.129, List.130):
+    let List.703 : {List {Str, I64}, {Str, I64}} = CallByName List.64 List.128 List.129 List.130;
+    let List.702 : List {Str, I64} = StructAtIndex 0 List.703;
+    let #Derived_gen.74 : {Str, I64} = StructAtIndex 1 List.703;
+    dec #Derived_gen.74;
+    ret List.702;
+
+procedure List.4 (List.136, List.137):
+    let List.712 : U64 = 1i64;
+    let List.710 : List {Str, I64} = CallByName List.70 List.136 List.712;
+    let List.709 : List {Str, I64} = CallByName List.71 List.710 List.137;
+    ret List.709;
+
+procedure List.6 (#Attr.2):
+    let List.691 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.691;
+
+procedure List.6 (#Attr.2):
+    let List.738 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.738;
+
+procedure List.6 (#Attr.2):
+    let List.750 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.750;
+
+procedure List.64 (List.125, List.126, List.127):
+    let List.699 : U64 = CallByName List.6 List.125;
+    let List.696 : Int1 = CallByName Num.22 List.126 List.699;
+    if List.696 then
+        let List.697 : {List {U32, U32}, {U32, U32}} = CallByName List.67 List.125 List.126 List.127;
        ret List.697;
+    else
+        let List.695 : {List {U32, U32}, {U32, U32}} = Struct {List.125, List.127};
+        ret List.695;

-procedure List.68 (#Attr.2):
-    let List.725 : List {U32, U32} = lowlevel ListWithCapacity #Attr.2;
-    ret List.725;
-
-procedure List.70 (#Attr.2, #Attr.3):
-    let List.703 : List {Str, I64} = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.703;
-
-procedure List.71 (#Attr.2, #Attr.3):
-    let List.701 : List {Str, I64} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.701;
-
-procedure List.71 (#Attr.2, #Attr.3):
-    let List.722 : List {U32, U32} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.722;
-
-procedure List.83 (List.180, List.181, List.182):
-    let List.705 : U64 = 0i64;
-    let List.706 : U64 = CallByName List.6 List.180;
-    let List.704 : List {U32, U32} = CallByName List.101 List.180 List.181 List.182 List.705 List.706;
+procedure List.64 (List.125, List.126, List.127):
+    let List.708 : U64 = CallByName List.6 List.125;
+    let List.705 : Int1 = CallByName Num.22 List.126 List.708;
+    if List.705 then
+        let List.706 : {List {Str, I64}, {Str, I64}} = CallByName List.67 List.125 List.126 List.127;
+        ret List.706;
+    else
+        let List.704 : {List {Str, I64}, {Str, I64}} = Struct {List.125, List.127};
        ret List.704;

-procedure List.98 (#Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
-    joinpoint List.716 List.151 List.152 List.153:
-        let List.724 : U64 = 0i64;
-        let List.718 : Int1 = CallByName Num.24 List.152 List.724;
-        if List.718 then
-            let List.723 : U64 = 1i64;
-            let List.720 : U64 = CallByName Num.75 List.152 List.723;
-            let List.721 : List {U32, U32} = CallByName List.71 List.153 List.151;
-            jump List.716 List.151 List.720 List.721;
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.749 : {Str, I64} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.749;
+
+procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
+    let List.698 : {List {U32, U32}, {U32, U32}} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.698;
+
+procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
+    let List.707 : {List {Str, I64}, {Str, I64}} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.707;
+
+procedure List.68 (#Attr.2):
+    let List.735 : List {U32, U32} = lowlevel ListWithCapacity #Attr.2;
+    ret List.735;
+
+procedure List.70 (#Attr.2, #Attr.3):
+    let List.713 : List {Str, I64} = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.713;
+
+procedure List.71 (#Attr.2, #Attr.3):
+    let List.711 : List {Str, I64} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.711;
+
+procedure List.71 (#Attr.2, #Attr.3):
+    let List.732 : List {U32, U32} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.732;
+
+procedure List.83 (List.181, List.182, List.183):
+    let List.715 : U64 = 0i64;
+    let List.716 : U64 = CallByName List.6 List.181;
+    let List.714 : List {U32, U32} = CallByName List.102 List.181 List.182 List.183 List.715 List.716;
+    ret List.714;
+
+procedure List.99 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22):
+    joinpoint List.726 List.152 List.153 List.154:
+        let List.734 : U64 = 0i64;
+        let List.728 : Int1 = CallByName Num.24 List.153 List.734;
+        if List.728 then
+            let List.733 : U64 = 1i64;
+            let List.730 : U64 = CallByName Num.75 List.153 List.733;
+            let List.731 : List {U32, U32} = CallByName List.71 List.154 List.152;
+            jump List.726 List.152 List.730 List.731;
        else
-            ret List.153;
+            ret List.154;
    in
-    jump List.716 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;
+    jump List.726 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22;

 procedure Num.131 (#Attr.2):
    let Num.291 : U32 = lowlevel NumIntCast #Attr.2;
@ -1279,7 +1279,7 @@ procedure Str.45 (Str.91, Str.92, Str.93):
        dec Str.344;
        ret Str.91;

-procedure Str.56 (#Derived_gen.51, #Derived_gen.52, #Derived_gen.53, #Derived_gen.54):
+procedure Str.56 (#Derived_gen.56, #Derived_gen.57, #Derived_gen.58, #Derived_gen.59):
    joinpoint Str.253 Str.96 Str.97 Str.98 Str.99:
        inc Str.97;
        let Str.254 : [C {}, C {Str, Str}] = CallByName Str.38 Str.97 Str.98;
@ -1303,9 +1303,9 @@ procedure Str.56 (#Derived_gen.51, #Derived_gen.52, #Derived_gen.53, #Derived_ge
            dec Str.97;
            ret Str.258;
    in
-    inc #Derived_gen.54;
-    inc #Derived_gen.53;
-    jump Str.253 #Derived_gen.51 #Derived_gen.52 #Derived_gen.53 #Derived_gen.54;
+    inc #Derived_gen.58;
+    inc #Derived_gen.59;
+    jump Str.253 #Derived_gen.56 #Derived_gen.57 #Derived_gen.58 #Derived_gen.59;

 procedure Str.57 (Str.121, Str.122):
    let Str.123 : U64 = CallByName Str.36 Str.121;
@ -1315,7 +1315,7 @@ procedure Str.57 (Str.121, Str.122):
    let Str.279 : [C , C U64] = CallByName Str.58 Str.121 Str.122 Str.280 Str.125;
    ret Str.279;

-procedure Str.58 (#Derived_gen.28, #Derived_gen.29, #Derived_gen.30, #Derived_gen.31):
+procedure Str.58 (#Derived_gen.33, #Derived_gen.34, #Derived_gen.35, #Derived_gen.36):
    joinpoint Str.281 Str.126 Str.127 Str.128 Str.129:
        let Str.283 : Int1 = CallByName Num.23 Str.128 Str.129;
        if Str.283 then
@ -1335,9 +1335,9 @@ procedure Str.58 (#Derived_gen.28, #Derived_gen.29, #Derived_gen.30, #Derived_ge
            let Str.282 : [C , C U64] = TagId(0) ;
            ret Str.282;
    in
-    inc #Derived_gen.29;
-    inc #Derived_gen.28;
-    jump Str.281 #Derived_gen.28 #Derived_gen.29 #Derived_gen.30 #Derived_gen.31;
+    inc #Derived_gen.34;
+    inc #Derived_gen.33;
+    jump Str.281 #Derived_gen.33 #Derived_gen.34 #Derived_gen.35 #Derived_gen.36;

 procedure Str.61 (Str.152, Str.153):
    let Str.311 : Int1 = CallByName Num.22 Str.152 Str.153;
--- a/crates/compiler/test_mono/generated/inspect_derived_list.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_list.txt
@ -120,35 +120,35 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.100 (#Derived_gen.8, #Derived_gen.9, #Derived_gen.10, #Derived_gen.11, #Derived_gen.12):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : I64 = CallByName List.66 List.174 List.177;
-            let List.179 : {Str, Int1} = CallByName Inspect.160 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14, #Derived_gen.15):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : I64 = CallByName List.66 List.175 List.178;
+            let List.180 : {Str, Int1} = CallByName Inspect.160 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.8;
-    jump List.668 #Derived_gen.8 #Derived_gen.9 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12;
+    inc #Derived_gen.11;
+    jump List.678 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14 #Derived_gen.15;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.285 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/inspect_derived_nested_record_string.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_nested_record_string.txt
@ -235,68 +235,68 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.100 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : {Str, Int1} = CallByName Inspect.229 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23, #Derived_gen.24):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : {Str, Int1} = CallByName Inspect.229 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.20;
-    jump List.668 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;
+    jump List.678 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23 #Derived_gen.24;

-procedure List.100 (#Derived_gen.42, #Derived_gen.43, #Derived_gen.44, #Derived_gen.45, #Derived_gen.46):
-    joinpoint List.680 List.174 List.175 List.176 List.177 List.178:
-        let List.682 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.682 then
-            let List.686 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.686;
-            let List.179 : {Str, Int1} = CallByName Inspect.229 List.175 List.686;
-            let List.685 : U64 = 1i64;
-            let List.684 : U64 = CallByName Num.51 List.177 List.685;
-            jump List.680 List.174 List.179 List.176 List.684 List.178;
+procedure List.101 (#Derived_gen.39, #Derived_gen.40, #Derived_gen.41, #Derived_gen.42, #Derived_gen.43):
+    joinpoint List.690 List.175 List.176 List.177 List.178 List.179:
+        let List.692 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.692 then
+            let List.696 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.696;
+            let List.180 : {Str, Int1} = CallByName Inspect.229 List.176 List.696;
+            let List.695 : U64 = 1i64;
+            let List.694 : U64 = CallByName Num.51 List.178 List.695;
+            jump List.690 List.175 List.180 List.177 List.694 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.42;
-    jump List.680 #Derived_gen.42 #Derived_gen.43 #Derived_gen.44 #Derived_gen.45 #Derived_gen.46;
+    inc #Derived_gen.39;
+    jump List.690 #Derived_gen.39 #Derived_gen.40 #Derived_gen.41 #Derived_gen.42 #Derived_gen.43;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.18 (List.171, List.172, List.173):
-    let List.678 : U64 = 0i64;
-    let List.679 : U64 = CallByName List.6 List.171;
-    let List.677 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.678 List.679;
-    ret List.677;
-
-procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
-
-procedure List.6 (#Attr.2):
-    let List.688 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.688;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

-procedure List.66 (#Attr.2, #Attr.3):
-    let List.687 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.688 : U64 = 0i64;
+    let List.689 : U64 = CallByName List.6 List.172;
+    let List.687 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.688 List.689;
    ret List.687;

+procedure List.6 (#Attr.2):
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;
+
+procedure List.6 (#Attr.2):
+    let List.698 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.698;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.697 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.697;
+
 procedure Num.20 (#Attr.2, #Attr.3):
    let Num.290 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
    ret Num.290;
--- a/crates/compiler/test_mono/generated/inspect_derived_record.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_record.txt
@ -150,36 +150,36 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.100 (#Derived_gen.16, #Derived_gen.17, #Derived_gen.18, #Derived_gen.19, #Derived_gen.20):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {[C I64, C Decimal], Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : {Str, Int1} = CallByName Inspect.229 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.18, #Derived_gen.19, #Derived_gen.20, #Derived_gen.21, #Derived_gen.22):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {[C I64, C Decimal], Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : {Str, Int1} = CallByName Inspect.229 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.16;
-    jump List.668 #Derived_gen.16 #Derived_gen.17 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20;
+    inc #Derived_gen.18;
+    jump List.678 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {[C I64, C Decimal], Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : {[C I64, C Decimal], Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.286 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/inspect_derived_record_one_field_string.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_record_one_field_string.txt
@ -160,36 +160,36 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.100 (#Derived_gen.12, #Derived_gen.13, #Derived_gen.14, #Derived_gen.15, #Derived_gen.16):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : {Str, Int1} = CallByName Inspect.229 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.10, #Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : {Str, Int1} = CallByName Inspect.229 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.12;
-    jump List.668 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14 #Derived_gen.15 #Derived_gen.16;
+    inc #Derived_gen.10;
+    jump List.678 #Derived_gen.10 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.20 (#Attr.2, #Attr.3):
    let Num.288 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/inspect_derived_record_two_field_strings.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_record_two_field_strings.txt
@ -167,36 +167,36 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.100 (#Derived_gen.16, #Derived_gen.17, #Derived_gen.18, #Derived_gen.19, #Derived_gen.20):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : {Str, Str} = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : {Str, Int1} = CallByName Inspect.229 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.14, #Derived_gen.15, #Derived_gen.16, #Derived_gen.17, #Derived_gen.18):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : {Str, Str} = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : {Str, Int1} = CallByName Inspect.229 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.16;
-    jump List.668 #Derived_gen.16 #Derived_gen.17 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20;
+    inc #Derived_gen.14;
+    jump List.678 #Derived_gen.14 #Derived_gen.15 #Derived_gen.16 #Derived_gen.17 #Derived_gen.18;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : {Str, Int1} = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : {Str, Int1} = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : {Str, Str} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.20 (#Attr.2, #Attr.3):
    let Num.288 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/inspect_derived_tag_one_field_string.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_tag_one_field_string.txt
@ -156,43 +156,43 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.1 (List.118):
-    let List.678 : U64 = CallByName List.6 List.118;
-    let List.679 : U64 = 0i64;
-    let List.677 : Int1 = CallByName Bool.11 List.678 List.679;
-    ret List.677;
+procedure List.1 (List.119):
+    let List.688 : U64 = CallByName List.6 List.119;
+    let List.689 : U64 = 0i64;
+    let List.687 : Int1 = CallByName Bool.11 List.688 List.689;
+    ret List.687;

-procedure List.100 (#Derived_gen.23, #Derived_gen.24, #Derived_gen.25, #Derived_gen.26, #Derived_gen.27):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : Str = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : Str = CallByName Inspect.207 List.175 List.674;
-            dec List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.11, #Derived_gen.12, #Derived_gen.13, #Derived_gen.14, #Derived_gen.15):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : Str = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : Str = CallByName Inspect.207 List.176 List.684;
+            dec List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.23;
-    jump List.668 #Derived_gen.23 #Derived_gen.24 #Derived_gen.25 #Derived_gen.26 #Derived_gen.27;
+    inc #Derived_gen.11;
+    jump List.678 #Derived_gen.11 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14 #Derived_gen.15;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : Str = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : Str = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.20 (#Attr.2, #Attr.3):
    let Num.288 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
@ -290,7 +290,7 @@ procedure Str.45 (Str.91, Str.92, Str.93):
        dec Str.341;
        ret Str.91;

-procedure Str.56 (#Derived_gen.19, #Derived_gen.20, #Derived_gen.21, #Derived_gen.22):
+procedure Str.56 (#Derived_gen.24, #Derived_gen.25, #Derived_gen.26, #Derived_gen.27):
    joinpoint Str.250 Str.96 Str.97 Str.98 Str.99:
        inc Str.97;
        let Str.251 : [C {}, C {Str, Str}] = CallByName Str.38 Str.97 Str.98;
@ -314,9 +314,9 @@ procedure Str.56 (#Derived_gen.19, #Derived_gen.20, #Derived_gen.21, #Derived_ge
            dec Str.97;
            ret Str.255;
    in
-    inc #Derived_gen.21;
-    inc #Derived_gen.22;
-    jump Str.250 #Derived_gen.19 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22;
+    inc #Derived_gen.27;
+    inc #Derived_gen.26;
+    jump Str.250 #Derived_gen.24 #Derived_gen.25 #Derived_gen.26 #Derived_gen.27;

 procedure Str.57 (Str.121, Str.122):
    let Str.123 : U64 = CallByName Str.36 Str.121;
@ -326,7 +326,7 @@ procedure Str.57 (Str.121, Str.122):
    let Str.276 : [C , C U64] = CallByName Str.58 Str.121 Str.122 Str.277 Str.125;
    ret Str.276;

-procedure Str.58 (#Derived_gen.13, #Derived_gen.14, #Derived_gen.15, #Derived_gen.16):
+procedure Str.58 (#Derived_gen.18, #Derived_gen.19, #Derived_gen.20, #Derived_gen.21):
    joinpoint Str.278 Str.126 Str.127 Str.128 Str.129:
        let Str.280 : Int1 = CallByName Num.23 Str.128 Str.129;
        if Str.280 then
@ -346,9 +346,9 @@ procedure Str.58 (#Derived_gen.13, #Derived_gen.14, #Derived_gen.15, #Derived_ge
            let Str.279 : [C , C U64] = TagId(0) ;
            ret Str.279;
    in
-    inc #Derived_gen.14;
-    inc #Derived_gen.13;
-    jump Str.278 #Derived_gen.13 #Derived_gen.14 #Derived_gen.15 #Derived_gen.16;
+    inc #Derived_gen.18;
+    inc #Derived_gen.19;
+    jump Str.278 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20 #Derived_gen.21;

 procedure Str.61 (Str.152, Str.153):
    let Str.308 : Int1 = CallByName Num.22 Str.152 Str.153;
--- a/crates/compiler/test_mono/generated/inspect_derived_tag_two_payloads_string.txt
+++ b/crates/compiler/test_mono/generated/inspect_derived_tag_two_payloads_string.txt
@ -159,43 +159,43 @@ procedure Inspect.63 (Inspect.295, Inspect.291):
 procedure Inspect.64 (Inspect.297):
    ret Inspect.297;

-procedure List.1 (List.118):
-    let List.678 : U64 = CallByName List.6 List.118;
-    let List.679 : U64 = 0i64;
-    let List.677 : Int1 = CallByName Bool.11 List.678 List.679;
-    ret List.677;
+procedure List.1 (List.119):
+    let List.688 : U64 = CallByName List.6 List.119;
+    let List.689 : U64 = 0i64;
+    let List.687 : Int1 = CallByName Bool.11 List.688 List.689;
+    ret List.687;

-procedure List.100 (#Derived_gen.18, #Derived_gen.19, #Derived_gen.20, #Derived_gen.21, #Derived_gen.22):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : Str = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : Str = CallByName Inspect.207 List.175 List.674;
-            dec List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.26, #Derived_gen.27, #Derived_gen.28, #Derived_gen.29, #Derived_gen.30):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : Str = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : Str = CallByName Inspect.207 List.176 List.684;
+            dec List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.18;
-    jump List.668 #Derived_gen.18 #Derived_gen.19 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22;
+    inc #Derived_gen.26;
+    jump List.678 #Derived_gen.26 #Derived_gen.27 #Derived_gen.28 #Derived_gen.29 #Derived_gen.30;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : Str = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : Str = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.20 (#Attr.2, #Attr.3):
    let Num.288 : U64 = lowlevel NumSub #Attr.2 #Attr.3;
@ -293,7 +293,7 @@ procedure Str.45 (Str.91, Str.92, Str.93):
        dec Str.385;
        ret Str.91;

-procedure Str.56 (#Derived_gen.25, #Derived_gen.26, #Derived_gen.27, #Derived_gen.28):
+procedure Str.56 (#Derived_gen.20, #Derived_gen.21, #Derived_gen.22, #Derived_gen.23):
    joinpoint Str.250 Str.96 Str.97 Str.98 Str.99:
        inc Str.97;
        let Str.251 : [C {}, C {Str, Str}] = CallByName Str.38 Str.97 Str.98;
@ -317,9 +317,9 @@ procedure Str.56 (#Derived_gen.25, #Derived_gen.26, #Derived_gen.27, #Derived_ge
            dec Str.97;
            ret Str.255;
    in
-    inc #Derived_gen.28;
-    inc #Derived_gen.27;
-    jump Str.250 #Derived_gen.25 #Derived_gen.26 #Derived_gen.27 #Derived_gen.28;
+    inc #Derived_gen.23;
+    inc #Derived_gen.22;
+    jump Str.250 #Derived_gen.20 #Derived_gen.21 #Derived_gen.22 #Derived_gen.23;

 procedure Str.57 (Str.121, Str.122):
    let Str.123 : U64 = CallByName Str.36 Str.121;
--- a/crates/compiler/test_mono/generated/ir_int_add.txt
+++ b/crates/compiler/test_mono/generated/ir_int_add.txt
@ -1,6 +1,6 @@
 procedure List.6 (#Attr.2):
-    let List.665 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.665;
+    let List.675 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.675;

 procedure Num.19 (#Attr.2, #Attr.3):
    let Num.285 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
--- 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
@ -6,40 +6,40 @@ procedure Bool.2 ():
    let Bool.23 : Int1 = true;
    ret Bool.23;

-procedure List.2 (List.119, List.120):
-    let List.679 : U64 = CallByName List.6 List.119;
-    let List.675 : Int1 = CallByName Num.22 List.120 List.679;
-    if List.675 then
-        let List.677 : I64 = CallByName List.66 List.119 List.120;
-        let List.676 : [C {}, C I64] = TagId(1) List.677;
-        ret List.676;
+procedure List.2 (List.120, List.121):
+    let List.689 : U64 = CallByName List.6 List.120;
+    let List.685 : Int1 = CallByName Num.22 List.121 List.689;
+    if List.685 then
+        let List.687 : I64 = CallByName List.66 List.120 List.121;
+        let List.686 : [C {}, C I64] = TagId(1) List.687;
+        ret List.686;
    else
-        let List.674 : {} = Struct {};
-        let List.673 : [C {}, C I64] = TagId(0) List.674;
-        ret List.673;
+        let List.684 : {} = Struct {};
+        let List.683 : [C {}, C I64] = TagId(0) List.684;
+        ret List.683;

 procedure List.6 (#Attr.2):
-    let List.680 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.680;
+    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.690;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.678 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.678;
+    let List.688 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.688;

-procedure List.9 (List.391):
-    let List.672 : U64 = 0i64;
-    let List.665 : [C {}, C I64] = CallByName List.2 List.391 List.672;
-    let List.669 : U8 = 1i64;
-    let List.670 : U8 = GetTagId List.665;
-    let List.671 : Int1 = lowlevel Eq List.669 List.670;
-    if List.671 then
-        let List.392 : I64 = UnionAtIndex (Id 1) (Index 0) List.665;
-        let List.666 : [C Int1, C I64] = TagId(1) List.392;
-        ret List.666;
+procedure List.9 (List.392):
+    let List.682 : U64 = 0i64;
+    let List.675 : [C {}, C I64] = CallByName List.2 List.392 List.682;
+    let List.679 : U8 = 1i64;
+    let List.680 : U8 = GetTagId List.675;
+    let List.681 : Int1 = lowlevel Eq List.679 List.680;
+    if List.681 then
+        let List.393 : I64 = UnionAtIndex (Id 1) (Index 0) List.675;
+        let List.676 : [C Int1, C I64] = TagId(1) List.393;
+        ret List.676;
    else
-        let List.668 : Int1 = true;
-        let List.667 : [C Int1, C I64] = TagId(0) List.668;
-        ret List.667;
+        let List.678 : Int1 = true;
+        let List.677 : [C Int1, C I64] = TagId(0) List.678;
+        ret List.677;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.283 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/issue_4770.txt
+++ b/crates/compiler/test_mono/generated/issue_4770.txt
@ -6,118 +6,118 @@ procedure Bool.2 ():
    let Bool.24 : Int1 = true;
    ret Bool.24;

-procedure List.105 (#Derived_gen.6, #Derived_gen.7, #Derived_gen.8, #Derived_gen.9, #Derived_gen.10, #Derived_gen.11):
-    joinpoint List.703 List.290 List.291 List.292 List.293 List.294 List.295:
-        let List.705 : Int1 = CallByName Num.22 List.294 List.295;
-        if List.705 then
-            let List.711 : [<r>C I64, C List *self] = CallByName List.66 List.290 List.294;
-            inc List.711;
-            let List.712 : [<r>C I64, C List *self] = CallByName List.66 List.291 List.294;
-            inc List.712;
-            let List.296 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName Test.15 List.711 List.712;
-            let List.707 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.71 List.292 List.296;
-            let List.709 : U64 = 1i64;
-            let List.708 : U64 = CallByName Num.51 List.294 List.709;
-            jump List.703 List.290 List.291 List.707 List.293 List.708 List.295;
+procedure List.106 (#Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4, #Derived_gen.5, #Derived_gen.6):
+    joinpoint List.713 List.291 List.292 List.293 List.294 List.295 List.296:
+        let List.715 : Int1 = CallByName Num.22 List.295 List.296;
+        if List.715 then
+            let List.721 : [<r>C I64, C List *self] = CallByName List.66 List.291 List.295;
+            inc List.721;
+            let List.722 : [<r>C I64, C List *self] = CallByName List.66 List.292 List.295;
+            inc List.722;
+            let List.297 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName Test.15 List.721 List.722;
+            let List.717 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.71 List.293 List.297;
+            let List.719 : U64 = 1i64;
+            let List.718 : U64 = CallByName Num.51 List.295 List.719;
+            jump List.713 List.291 List.292 List.717 List.294 List.718 List.296;
        else
            dec List.291;
-            dec List.290;
-            ret List.292;
+            dec List.292;
+            ret List.293;
    in
-    inc #Derived_gen.6;
-    inc #Derived_gen.7;
-    jump List.703 #Derived_gen.6 #Derived_gen.7 #Derived_gen.8 #Derived_gen.9 #Derived_gen.10 #Derived_gen.11;
+    inc #Derived_gen.1;
+    inc #Derived_gen.2;
+    jump List.713 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6;

-procedure List.115 (List.562, List.563, List.564):
-    let List.679 : U64 = 0i64;
-    let List.680 : U64 = CallByName List.6 List.562;
-    let List.678 : [C {}, C {}] = CallByName List.80 List.562 List.563 List.564 List.679 List.680;
-    ret List.678;
+procedure List.116 (List.563, List.564, List.565):
+    let List.689 : U64 = 0i64;
+    let List.690 : U64 = CallByName List.6 List.563;
+    let List.688 : [C {}, C {}] = CallByName List.80 List.563 List.564 List.565 List.689 List.690;
+    ret List.688;

-procedure List.23 (List.286, List.287, List.288):
-    let List.715 : U64 = CallByName List.6 List.286;
-    let List.716 : U64 = CallByName List.6 List.287;
-    let List.289 : U64 = CallByName Num.148 List.715 List.716;
-    let List.701 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.68 List.289;
-    let List.702 : U64 = 0i64;
-    let List.700 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.105 List.286 List.287 List.701 List.288 List.702 List.289;
-    ret List.700;
-
-procedure List.247 (List.667, List.248, List.246):
-    let List.697 : Int1 = CallByName Test.1 List.248;
-    if List.697 then
-        let List.699 : {} = Struct {};
-        let List.698 : [C {}, C {}] = TagId(1) List.699;
-        ret List.698;
-    else
-        let List.696 : {} = Struct {};
-        let List.695 : [C {}, C {}] = TagId(0) List.696;
-        ret List.695;
-
-procedure List.56 (List.245, List.246):
-    let List.676 : {} = Struct {};
-    let List.668 : [C {}, C {}] = CallByName List.115 List.245 List.676 List.246;
-    let List.673 : U8 = 1i64;
-    let List.674 : U8 = GetTagId List.668;
-    let List.675 : Int1 = lowlevel Eq List.673 List.674;
-    if List.675 then
-        let List.669 : Int1 = CallByName Bool.2;
-        ret List.669;
-    else
-        let List.670 : Int1 = CallByName Bool.1;
-        ret List.670;
-
-procedure List.6 (#Attr.2):
-    let List.666 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.666;
-
-procedure List.6 (#Attr.2):
-    let List.694 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.694;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.693 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.693;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.713 : [<r>C I64, C List *self] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.713;
-
-procedure List.68 (#Attr.2):
-    let List.714 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = lowlevel ListWithCapacity #Attr.2;
-    ret List.714;
-
-procedure List.71 (#Attr.2, #Attr.3):
-    let List.710 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+procedure List.23 (List.287, List.288, List.289):
+    let List.725 : U64 = CallByName List.6 List.287;
+    let List.726 : U64 = CallByName List.6 List.288;
+    let List.290 : U64 = CallByName Num.148 List.725 List.726;
+    let List.711 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.68 List.290;
+    let List.712 : U64 = 0i64;
+    let List.710 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.106 List.287 List.288 List.711 List.289 List.712 List.290;
    ret List.710;

-procedure List.80 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.681 List.565 List.566 List.567 List.568 List.569:
-        let List.683 : Int1 = CallByName Num.22 List.568 List.569;
-        if List.683 then
-            let List.692 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.66 List.565 List.568;
-            inc List.692;
-            let List.684 : [C {}, C {}] = CallByName List.247 List.566 List.692 List.567;
-            let List.689 : U8 = 1i64;
-            let List.690 : U8 = GetTagId List.684;
-            let List.691 : Int1 = lowlevel Eq List.689 List.690;
-            if List.691 then
-                let List.570 : {} = UnionAtIndex (Id 1) (Index 0) List.684;
-                let List.687 : U64 = 1i64;
-                let List.686 : U64 = CallByName Num.51 List.568 List.687;
-                jump List.681 List.565 List.570 List.567 List.686 List.569;
+procedure List.248 (List.677, List.249, List.247):
+    let List.707 : Int1 = CallByName Test.1 List.249;
+    if List.707 then
+        let List.709 : {} = Struct {};
+        let List.708 : [C {}, C {}] = TagId(1) List.709;
+        ret List.708;
    else
-                dec List.565;
-                let List.571 : {} = UnionAtIndex (Id 0) (Index 0) List.684;
-                let List.688 : [C {}, C {}] = TagId(0) List.571;
-                ret List.688;
+        let List.706 : {} = Struct {};
+        let List.705 : [C {}, C {}] = TagId(0) List.706;
+        ret List.705;
+
+procedure List.56 (List.246, List.247):
+    let List.686 : {} = Struct {};
+    let List.678 : [C {}, C {}] = CallByName List.116 List.246 List.686 List.247;
+    let List.683 : U8 = 1i64;
+    let List.684 : U8 = GetTagId List.678;
+    let List.685 : Int1 = lowlevel Eq List.683 List.684;
+    if List.685 then
+        let List.679 : Int1 = CallByName Bool.2;
+        ret List.679;
    else
-            dec List.565;
-            let List.682 : [C {}, C {}] = TagId(1) List.566;
-            ret List.682;
+        let List.680 : Int1 = CallByName Bool.1;
+        ret List.680;
+
+procedure List.6 (#Attr.2):
+    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.676;
+
+procedure List.6 (#Attr.2):
+    let List.704 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.704;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.703 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.703;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.723 : [<r>C I64, C List *self] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.723;
+
+procedure List.68 (#Attr.2):
+    let List.724 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = lowlevel ListWithCapacity #Attr.2;
+    ret List.724;
+
+procedure List.71 (#Attr.2, #Attr.3):
+    let List.720 : List {[<r>C I64, C List *self], [<r>C I64, C List *self]} = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.720;
+
+procedure List.80 (#Derived_gen.7, #Derived_gen.8, #Derived_gen.9, #Derived_gen.10, #Derived_gen.11):
+    joinpoint List.691 List.566 List.567 List.568 List.569 List.570:
+        let List.693 : Int1 = CallByName Num.22 List.569 List.570;
+        if List.693 then
+            let List.702 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = CallByName List.66 List.566 List.569;
+            inc List.702;
+            let List.694 : [C {}, C {}] = CallByName List.248 List.567 List.702 List.568;
+            let List.699 : U8 = 1i64;
+            let List.700 : U8 = GetTagId List.694;
+            let List.701 : Int1 = lowlevel Eq List.699 List.700;
+            if List.701 then
+                let List.571 : {} = UnionAtIndex (Id 1) (Index 0) List.694;
+                let List.697 : U64 = 1i64;
+                let List.696 : U64 = CallByName Num.51 List.569 List.697;
+                jump List.691 List.566 List.571 List.568 List.696 List.570;
+            else
+                dec List.566;
+                let List.572 : {} = UnionAtIndex (Id 0) (Index 0) List.694;
+                let List.698 : [C {}, C {}] = TagId(0) List.572;
+                ret List.698;
+        else
+            dec List.566;
+            let List.692 : [C {}, C {}] = TagId(1) List.567;
+            ret List.692;
    in
-    inc #Derived_gen.0;
-    jump List.681 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    inc #Derived_gen.7;
+    jump List.691 #Derived_gen.7 #Derived_gen.8 #Derived_gen.9 #Derived_gen.10 #Derived_gen.11;

 procedure Num.148 (Num.226, Num.227):
    let Num.290 : Int1 = CallByName Num.22 Num.226 Num.227;
@ -138,7 +138,7 @@ procedure Num.51 (#Attr.2, #Attr.3):
    let Num.286 : U64 = lowlevel NumAddWrap #Attr.2 #Attr.3;
    ret Num.286;

-procedure Test.1 (#Derived_gen.5):
+procedure Test.1 (#Derived_gen.0):
    joinpoint Test.26 Test.6:
        let Test.65 : [<r>C I64, C List *self] = StructAtIndex 1 Test.6;
        let Test.66 : U8 = 0i64;
@ -220,7 +220,7 @@ procedure Test.1 (#Derived_gen.5):
                let Test.44 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = Struct {Test.45, Test.46};
                jump Test.26 Test.44;
    in
-    jump Test.26 #Derived_gen.5;
+    jump Test.26 #Derived_gen.0;

 procedure Test.15 (Test.16, Test.17):
    let Test.36 : {[<r>C I64, C List *self], [<r>C I64, C List *self]} = Struct {Test.16, Test.17};
--- a/crates/compiler/test_mono/generated/layout_cache_structure_with_multiple_recursive_structures.txt
+++ b/crates/compiler/test_mono/generated/layout_cache_structure_with_multiple_recursive_structures.txt
@ -1,33 +1,33 @@
-procedure List.100 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : [<rnu>C *self, <null>] = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : [<rnu><null>, C {[<rnu>C *self, <null>], *self}] = CallByName Test.7 List.175 List.674;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : [<rnu>C *self, <null>] = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : [<rnu><null>, C {[<rnu>C *self, <null>], *self}] = CallByName Test.7 List.176 List.684;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.0;
-    jump List.668 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    jump List.678 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : [<rnu><null>, C {[<rnu>C *self, <null>], *self}] = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : [<rnu><null>, C {[<rnu>C *self, <null>], *self}] = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.676;
+    let List.686 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.686;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : [<rnu>C *self, <null>] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.675;
+    let List.685 : [<rnu>C *self, <null>] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- 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.135, List.136):
-    let List.668 : U64 = 1i64;
-    let List.666 : List I64 = CallByName List.70 List.135 List.668;
-    let List.665 : List I64 = CallByName List.71 List.666 List.136;
-    ret List.665;
+procedure List.4 (List.136, List.137):
+    let List.678 : U64 = 1i64;
+    let List.676 : List I64 = CallByName List.70 List.136 List.678;
+    let List.675 : List I64 = CallByName List.71 List.676 List.137;
+    ret List.675;

 procedure List.70 (#Attr.2, #Attr.3):
-    let List.669 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.669;
+    let List.679 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.679;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.667 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.667;
+    let List.677 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.677;

 procedure Test.0 ():
    let Test.2 : List I64 = Array [1i64];
--- 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.135, List.136):
-    let List.668 : U64 = 1i64;
-    let List.666 : List I64 = CallByName List.70 List.135 List.668;
-    let List.665 : List I64 = CallByName List.71 List.666 List.136;
-    ret List.665;
+procedure List.4 (List.136, List.137):
+    let List.678 : U64 = 1i64;
+    let List.676 : List I64 = CallByName List.70 List.136 List.678;
+    let List.675 : List I64 = CallByName List.71 List.676 List.137;
+    ret List.675;

 procedure List.70 (#Attr.2, #Attr.3):
-    let List.669 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.669;
+    let List.679 : List I64 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.679;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.667 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.667;
+    let List.677 : List I64 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.677;

 procedure Test.1 (Test.2):
    let Test.6 : I64 = 42i64;
--- a/crates/compiler/test_mono/generated/list_cannot_update_inplace.txt
+++ b/crates/compiler/test_mono/generated/list_cannot_update_inplace.txt
@ -1,25 +1,25 @@
-procedure List.3 (List.127, List.128, List.129):
-    let List.668 : {List I64, I64} = CallByName List.64 List.127 List.128 List.129;
-    let List.667 : List I64 = StructAtIndex 0 List.668;
-    ret List.667;
+procedure List.3 (List.128, List.129, List.130):
+    let List.678 : {List I64, I64} = CallByName List.64 List.128 List.129 List.130;
+    let List.677 : List I64 = StructAtIndex 0 List.678;
+    ret List.677;

 procedure List.6 (#Attr.2):
-    let List.666 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.666;
+    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.676;

-procedure List.64 (List.124, List.125, List.126):
-    let List.673 : U64 = CallByName List.6 List.124;
-    let List.670 : Int1 = CallByName Num.22 List.125 List.673;
-    if List.670 then
-        let List.671 : {List I64, I64} = CallByName List.67 List.124 List.125 List.126;
-        ret List.671;
+procedure List.64 (List.125, List.126, List.127):
+    let List.683 : U64 = CallByName List.6 List.125;
+    let List.680 : Int1 = CallByName Num.22 List.126 List.683;
+    if List.680 then
+        let List.681 : {List I64, I64} = CallByName List.67 List.125 List.126 List.127;
+        ret List.681;
    else
-        let List.669 : {List I64, I64} = Struct {List.124, List.126};
-        ret List.669;
+        let List.679 : {List I64, I64} = Struct {List.125, List.127};
+        ret List.679;

 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.672 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.672;
+    let List.682 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.682;

 procedure Num.19 (#Attr.2, #Attr.3):
    let Num.283 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_get.txt
+++ b/crates/compiler/test_mono/generated/list_get.txt
@ -1,22 +1,22 @@
-procedure List.2 (List.119, List.120):
-    let List.671 : U64 = CallByName List.6 List.119;
-    let List.667 : Int1 = CallByName Num.22 List.120 List.671;
-    if List.667 then
-        let List.669 : I64 = CallByName List.66 List.119 List.120;
-        let List.668 : [C {}, C I64] = TagId(1) List.669;
-        ret List.668;
+procedure List.2 (List.120, List.121):
+    let List.681 : U64 = CallByName List.6 List.120;
+    let List.677 : Int1 = CallByName Num.22 List.121 List.681;
+    if List.677 then
+        let List.679 : I64 = CallByName List.66 List.120 List.121;
+        let List.678 : [C {}, C I64] = TagId(1) List.679;
+        ret List.678;
    else
-        let List.666 : {} = Struct {};
-        let List.665 : [C {}, C I64] = TagId(0) List.666;
-        ret List.665;
+        let List.676 : {} = Struct {};
+        let List.675 : [C {}, C I64] = TagId(0) List.676;
+        ret List.675;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.670 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.670;
+    let List.680 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.680;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.283 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_len.txt
+++ b/crates/compiler/test_mono/generated/list_len.txt
@ -1,10 +1,10 @@
 procedure List.6 (#Attr.2):
-    let List.665 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.665;
+    let List.675 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.666 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.666;
+    let List.676 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.676;

 procedure Num.19 (#Attr.2, #Attr.3):
    let Num.283 : U64 = lowlevel NumAdd #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_map_closure_borrows.txt
+++ b/crates/compiler/test_mono/generated/list_map_closure_borrows.txt
@ -1,66 +1,66 @@
-procedure List.100 (#Derived_gen.3, #Derived_gen.4, #Derived_gen.5, #Derived_gen.6, #Derived_gen.7):
-    joinpoint List.679 List.174 List.175 List.176 List.177 List.178:
-        let List.681 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.681 then
-            let List.685 : Str = CallByName List.66 List.174 List.177;
-            inc List.685;
-            let List.179 : List Str = CallByName List.283 List.175 List.685 List.176;
-            dec List.685;
-            let List.684 : U64 = 1i64;
-            let List.683 : U64 = CallByName Num.51 List.177 List.684;
-            jump List.679 List.174 List.179 List.176 List.683 List.178;
+procedure List.101 (#Derived_gen.3, #Derived_gen.4, #Derived_gen.5, #Derived_gen.6, #Derived_gen.7):
+    joinpoint List.689 List.175 List.176 List.177 List.178 List.179:
+        let List.691 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.691 then
+            let List.695 : Str = CallByName List.66 List.175 List.178;
+            inc List.695;
+            let List.180 : List Str = CallByName List.284 List.176 List.695 List.177;
+            dec List.695;
+            let List.694 : U64 = 1i64;
+            let List.693 : U64 = CallByName Num.51 List.178 List.694;
+            jump List.689 List.175 List.180 List.177 List.693 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.3;
-    jump List.679 #Derived_gen.3 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7;
+    jump List.689 #Derived_gen.3 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7;

-procedure List.18 (List.171, List.172, List.173):
-    let List.677 : U64 = 0i64;
-    let List.678 : U64 = CallByName List.6 List.171;
-    let List.676 : List Str = CallByName List.100 List.171 List.172 List.173 List.677 List.678;
-    ret List.676;
+procedure List.18 (List.172, List.173, List.174):
+    let List.687 : U64 = 0i64;
+    let List.688 : U64 = CallByName List.6 List.172;
+    let List.686 : List Str = CallByName List.101 List.172 List.173 List.174 List.687 List.688;
+    ret List.686;

-procedure List.2 (List.119, List.120):
-    let List.671 : U64 = CallByName List.6 List.119;
-    let List.667 : Int1 = CallByName Num.22 List.120 List.671;
-    if List.667 then
-        let List.669 : Str = CallByName List.66 List.119 List.120;
-        inc List.669;
-        let List.668 : [C {}, C Str] = TagId(1) List.669;
-        ret List.668;
+procedure List.2 (List.120, List.121):
+    let List.681 : U64 = CallByName List.6 List.120;
+    let List.677 : Int1 = CallByName Num.22 List.121 List.681;
+    if List.677 then
+        let List.679 : Str = CallByName List.66 List.120 List.121;
+        inc List.679;
+        let List.678 : [C {}, C Str] = TagId(1) List.679;
+        ret List.678;
    else
-        let List.666 : {} = Struct {};
-        let List.665 : [C {}, C Str] = TagId(0) List.666;
-        ret List.665;
+        let List.676 : {} = Struct {};
+        let List.675 : [C {}, C Str] = TagId(0) List.676;
+        ret List.675;

-procedure List.283 (List.284, List.285, List.281):
-    let List.688 : Str = CallByName Test.3 List.285;
-    let List.687 : List Str = CallByName List.71 List.284 List.688;
-    ret List.687;
+procedure List.284 (List.285, List.286, List.282):
+    let List.698 : Str = CallByName Test.3 List.286;
+    let List.697 : List Str = CallByName List.71 List.285 List.698;
+    ret List.697;

-procedure List.5 (List.280, List.281):
-    let List.282 : U64 = CallByName List.6 List.280;
-    let List.674 : List Str = CallByName List.68 List.282;
-    let List.673 : List Str = CallByName List.18 List.280 List.674 List.281;
-    ret List.673;
+procedure List.5 (List.281, List.282):
+    let List.283 : U64 = CallByName List.6 List.281;
+    let List.684 : List Str = CallByName List.68 List.283;
+    let List.683 : List Str = CallByName List.18 List.281 List.684 List.282;
+    ret List.683;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.670 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.670;
+    let List.680 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.680;

 procedure List.68 (#Attr.2):
-    let List.690 : List Str = lowlevel ListWithCapacity #Attr.2;
-    ret List.690;
+    let List.700 : List Str = lowlevel ListWithCapacity #Attr.2;
+    ret List.700;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.689 : List Str = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List Str = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_map_closure_owns.txt
+++ b/crates/compiler/test_mono/generated/list_map_closure_owns.txt
@ -1,65 +1,65 @@
-procedure List.100 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.679 List.174 List.175 List.176 List.177 List.178:
-        let List.681 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.681 then
-            let List.685 : Str = CallByName List.66 List.174 List.177;
-            inc List.685;
-            let List.179 : List Str = CallByName List.283 List.175 List.685 List.176;
-            let List.684 : U64 = 1i64;
-            let List.683 : U64 = CallByName Num.51 List.177 List.684;
-            jump List.679 List.174 List.179 List.176 List.683 List.178;
+procedure List.101 (#Derived_gen.3, #Derived_gen.4, #Derived_gen.5, #Derived_gen.6, #Derived_gen.7):
+    joinpoint List.689 List.175 List.176 List.177 List.178 List.179:
+        let List.691 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.691 then
+            let List.695 : Str = CallByName List.66 List.175 List.178;
+            inc List.695;
+            let List.180 : List Str = CallByName List.284 List.176 List.695 List.177;
+            let List.694 : U64 = 1i64;
+            let List.693 : U64 = CallByName Num.51 List.178 List.694;
+            jump List.689 List.175 List.180 List.177 List.693 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.0;
-    jump List.679 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    inc #Derived_gen.3;
+    jump List.689 #Derived_gen.3 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7;

-procedure List.18 (List.171, List.172, List.173):
-    let List.677 : U64 = 0i64;
-    let List.678 : U64 = CallByName List.6 List.171;
-    let List.676 : List Str = CallByName List.100 List.171 List.172 List.173 List.677 List.678;
-    ret List.676;
+procedure List.18 (List.172, List.173, List.174):
+    let List.687 : U64 = 0i64;
+    let List.688 : U64 = CallByName List.6 List.172;
+    let List.686 : List Str = CallByName List.101 List.172 List.173 List.174 List.687 List.688;
+    ret List.686;

-procedure List.2 (List.119, List.120):
-    let List.671 : U64 = CallByName List.6 List.119;
-    let List.667 : Int1 = CallByName Num.22 List.120 List.671;
-    if List.667 then
-        let List.669 : Str = CallByName List.66 List.119 List.120;
-        inc List.669;
-        let List.668 : [C {}, C Str] = TagId(1) List.669;
-        ret List.668;
+procedure List.2 (List.120, List.121):
+    let List.681 : U64 = CallByName List.6 List.120;
+    let List.677 : Int1 = CallByName Num.22 List.121 List.681;
+    if List.677 then
+        let List.679 : Str = CallByName List.66 List.120 List.121;
+        inc List.679;
+        let List.678 : [C {}, C Str] = TagId(1) List.679;
+        ret List.678;
    else
-        let List.666 : {} = Struct {};
-        let List.665 : [C {}, C Str] = TagId(0) List.666;
-        ret List.665;
+        let List.676 : {} = Struct {};
+        let List.675 : [C {}, C Str] = TagId(0) List.676;
+        ret List.675;

-procedure List.283 (List.284, List.285, List.281):
-    let List.688 : Str = CallByName Test.3 List.285;
-    let List.687 : List Str = CallByName List.71 List.284 List.688;
-    ret List.687;
+procedure List.284 (List.285, List.286, List.282):
+    let List.698 : Str = CallByName Test.3 List.286;
+    let List.697 : List Str = CallByName List.71 List.285 List.698;
+    ret List.697;

-procedure List.5 (List.280, List.281):
-    let List.282 : U64 = CallByName List.6 List.280;
-    let List.674 : List Str = CallByName List.68 List.282;
-    let List.673 : List Str = CallByName List.18 List.280 List.674 List.281;
-    ret List.673;
+procedure List.5 (List.281, List.282):
+    let List.283 : U64 = CallByName List.6 List.281;
+    let List.684 : List Str = CallByName List.68 List.283;
+    let List.683 : List Str = CallByName List.18 List.281 List.684 List.282;
+    ret List.683;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.670 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.670;
+    let List.680 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.680;

 procedure List.68 (#Attr.2):
-    let List.690 : List Str = lowlevel ListWithCapacity #Attr.2;
-    ret List.690;
+    let List.700 : List Str = lowlevel ListWithCapacity #Attr.2;
+    ret List.700;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.689 : List Str = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List Str = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_map_take_capturing_or_noncapturing.txt
+++ b/crates/compiler/test_mono/generated/list_map_take_capturing_or_noncapturing.txt
@ -1,66 +1,66 @@
-procedure List.100 (#Derived_gen.3, #Derived_gen.4, #Derived_gen.5, #Derived_gen.6, #Derived_gen.7):
-    joinpoint List.671 List.174 List.175 List.176 List.177 List.178:
-        let List.673 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.673 then
-            let List.677 : U8 = CallByName List.66 List.174 List.177;
-            let List.179 : List U8 = CallByName List.283 List.175 List.677 List.176;
-            let List.676 : U64 = 1i64;
-            let List.675 : U64 = CallByName Num.51 List.177 List.676;
-            jump List.671 List.174 List.179 List.176 List.675 List.178;
+procedure List.101 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
+    joinpoint List.681 List.175 List.176 List.177 List.178 List.179:
+        let List.683 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.683 then
+            let List.687 : U8 = CallByName List.66 List.175 List.178;
+            let List.180 : List U8 = CallByName List.284 List.176 List.687 List.177;
+            let List.686 : U64 = 1i64;
+            let List.685 : U64 = CallByName Num.51 List.178 List.686;
+            jump List.681 List.175 List.180 List.177 List.685 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.3;
-    jump List.671 #Derived_gen.3 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7;
+    inc #Derived_gen.0;
+    jump List.681 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

-procedure List.18 (List.171, List.172, List.173):
-    let List.669 : U64 = 0i64;
-    let List.670 : U64 = CallByName List.6 List.171;
-    let List.668 : List U8 = CallByName List.100 List.171 List.172 List.173 List.669 List.670;
-    ret List.668;
-
-procedure List.283 (List.284, List.285, List.281):
-    let List.684 : U8 = GetTagId List.281;
-    joinpoint List.685 List.682:
-        let List.681 : List U8 = CallByName List.71 List.284 List.682;
-        ret List.681;
-    in
-    switch List.684:
-        case 0:
-            let List.686 : U8 = CallByName Test.4 List.285 List.281;
-            jump List.685 List.686;
-    
-        case 1:
-            let List.686 : U8 = CallByName Test.6 List.285 List.281;
-            jump List.685 List.686;
-    
-        default:
-            let List.686 : U8 = CallByName Test.8 List.285;
-            jump List.685 List.686;
-    
-
-procedure List.5 (List.280, List.281):
-    let List.282 : U64 = CallByName List.6 List.280;
-    let List.666 : List U8 = CallByName List.68 List.282;
-    let List.665 : List U8 = CallByName List.18 List.280 List.666 List.281;
-    ret List.665;
-
-procedure List.6 (#Attr.2):
-    let List.679 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.679;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.678 : U8 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.679 : U64 = 0i64;
+    let List.680 : U64 = CallByName List.6 List.172;
+    let List.678 : List U8 = CallByName List.101 List.172 List.173 List.174 List.679 List.680;
    ret List.678;

+procedure List.284 (List.285, List.286, List.282):
+    let List.694 : U8 = GetTagId List.282;
+    joinpoint List.695 List.692:
+        let List.691 : List U8 = CallByName List.71 List.285 List.692;
+        ret List.691;
+    in
+    switch List.694:
+        case 0:
+            let List.696 : U8 = CallByName Test.4 List.286 List.282;
+            jump List.695 List.696;
+    
+        case 1:
+            let List.696 : U8 = CallByName Test.6 List.286 List.282;
+            jump List.695 List.696;
+    
+        default:
+            let List.696 : U8 = CallByName Test.8 List.286;
+            jump List.695 List.696;
+    
+
+procedure List.5 (List.281, List.282):
+    let List.283 : U64 = CallByName List.6 List.281;
+    let List.676 : List U8 = CallByName List.68 List.283;
+    let List.675 : List U8 = CallByName List.18 List.281 List.676 List.282;
+    ret List.675;
+
+procedure List.6 (#Attr.2):
+    let List.689 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.689;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.688 : U8 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.688;
+
 procedure List.68 (#Attr.2):
-    let List.687 : List U8 = lowlevel ListWithCapacity #Attr.2;
-    ret List.687;
+    let List.697 : List U8 = lowlevel ListWithCapacity #Attr.2;
+    ret List.697;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.683 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.683;
+    let List.693 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.693;

 procedure Num.19 (#Attr.2, #Attr.3):
    let Num.285 : U8 = lowlevel NumAdd #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_pass_to_function.txt
+++ b/crates/compiler/test_mono/generated/list_pass_to_function.txt
@ -1,25 +1,25 @@
-procedure List.3 (List.127, List.128, List.129):
-    let List.666 : {List I64, I64} = CallByName List.64 List.127 List.128 List.129;
-    let List.665 : List I64 = StructAtIndex 0 List.666;
-    ret List.665;
+procedure List.3 (List.128, List.129, List.130):
+    let List.676 : {List I64, I64} = CallByName List.64 List.128 List.129 List.130;
+    let List.675 : List I64 = StructAtIndex 0 List.676;
+    ret List.675;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

-procedure List.64 (List.124, List.125, List.126):
-    let List.671 : U64 = CallByName List.6 List.124;
-    let List.668 : Int1 = CallByName Num.22 List.125 List.671;
-    if List.668 then
-        let List.669 : {List I64, I64} = CallByName List.67 List.124 List.125 List.126;
-        ret List.669;
+procedure List.64 (List.125, List.126, List.127):
+    let List.681 : U64 = CallByName List.6 List.125;
+    let List.678 : Int1 = CallByName Num.22 List.126 List.681;
+    if List.678 then
+        let List.679 : {List I64, I64} = CallByName List.67 List.125 List.126 List.127;
+        ret List.679;
    else
-        let List.667 : {List I64, I64} = Struct {List.124, List.126};
-        ret List.667;
+        let List.677 : {List I64, I64} = Struct {List.125, List.127};
+        ret List.677;

 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.670 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.670;
+    let List.680 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.680;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.283 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/list_sort_asc.txt
+++ b/crates/compiler/test_mono/generated/list_sort_asc.txt
@ -1,11 +1,11 @@
 procedure List.28 (#Attr.2, #Attr.3):
-    let List.667 : List I64 = lowlevel ListSortWith { xs: `#Attr.#arg1` } #Attr.2 Num.46 #Attr.3;
-    ret List.667;
+    let List.677 : List I64 = lowlevel ListSortWith { xs: `#Attr.#arg1` } #Attr.2 Num.46 #Attr.3;
+    ret List.677;

-procedure List.59 (List.386):
-    let List.666 : {} = Struct {};
-    let List.665 : List I64 = CallByName List.28 List.386 List.666;
-    ret List.665;
+procedure List.59 (List.387):
+    let List.676 : {} = Struct {};
+    let List.675 : List I64 = CallByName List.28 List.387 List.676;
+    ret List.675;

 procedure Num.46 (#Attr.2, #Attr.3):
    let Num.283 : U8 = lowlevel NumCompare #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/quicksort_swap.txt
+++ b/crates/compiler/test_mono/generated/quicksort_swap.txt
@ -1,41 +1,41 @@
-procedure List.2 (List.119, List.120):
-    let List.687 : U64 = CallByName List.6 List.119;
-    let List.684 : Int1 = CallByName Num.22 List.120 List.687;
-    if List.684 then
-        let List.686 : I64 = CallByName List.66 List.119 List.120;
-        let List.685 : [C {}, C I64] = TagId(1) List.686;
-        ret List.685;
+procedure List.2 (List.120, List.121):
+    let List.697 : U64 = CallByName List.6 List.120;
+    let List.694 : Int1 = CallByName Num.22 List.121 List.697;
+    if List.694 then
+        let List.696 : I64 = CallByName List.66 List.120 List.121;
+        let List.695 : [C {}, C I64] = TagId(1) List.696;
+        ret List.695;
    else
-        let List.683 : {} = Struct {};
-        let List.682 : [C {}, C I64] = TagId(0) List.683;
-        ret List.682;
+        let List.693 : {} = Struct {};
+        let List.692 : [C {}, C I64] = TagId(0) List.693;
+        ret List.692;

-procedure List.3 (List.127, List.128, List.129):
-    let List.674 : {List I64, I64} = CallByName List.64 List.127 List.128 List.129;
-    let List.673 : List I64 = StructAtIndex 0 List.674;
-    ret List.673;
+procedure List.3 (List.128, List.129, List.130):
+    let List.684 : {List I64, I64} = CallByName List.64 List.128 List.129 List.130;
+    let List.683 : List I64 = StructAtIndex 0 List.684;
+    ret List.683;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

-procedure List.64 (List.124, List.125, List.126):
-    let List.671 : U64 = CallByName List.6 List.124;
-    let List.668 : Int1 = CallByName Num.22 List.125 List.671;
-    if List.668 then
-        let List.669 : {List I64, I64} = CallByName List.67 List.124 List.125 List.126;
-        ret List.669;
+procedure List.64 (List.125, List.126, List.127):
+    let List.681 : U64 = CallByName List.6 List.125;
+    let List.678 : Int1 = CallByName Num.22 List.126 List.681;
+    if List.678 then
+        let List.679 : {List I64, I64} = CallByName List.67 List.125 List.126 List.127;
+        ret List.679;
    else
-        let List.667 : {List I64, I64} = Struct {List.124, List.126};
-        ret List.667;
+        let List.677 : {List I64, I64} = Struct {List.125, List.127};
+        ret List.677;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.680 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.680;
+    let List.690 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.690;

 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.670 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.670;
+    let List.680 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.680;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.285 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/record_update.txt
+++ b/crates/compiler/test_mono/generated/record_update.txt
@ -1,25 +1,25 @@
-procedure List.3 (List.127, List.128, List.129):
-    let List.674 : {List U64, U64} = CallByName List.64 List.127 List.128 List.129;
-    let List.673 : List U64 = StructAtIndex 0 List.674;
-    ret List.673;
+procedure List.3 (List.128, List.129, List.130):
+    let List.684 : {List U64, U64} = CallByName List.64 List.128 List.129 List.130;
+    let List.683 : List U64 = StructAtIndex 0 List.684;
+    ret List.683;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

-procedure List.64 (List.124, List.125, List.126):
-    let List.671 : U64 = CallByName List.6 List.124;
-    let List.668 : Int1 = CallByName Num.22 List.125 List.671;
-    if List.668 then
-        let List.669 : {List U64, U64} = CallByName List.67 List.124 List.125 List.126;
-        ret List.669;
+procedure List.64 (List.125, List.126, List.127):
+    let List.681 : U64 = CallByName List.6 List.125;
+    let List.678 : Int1 = CallByName Num.22 List.126 List.681;
+    if List.678 then
+        let List.679 : {List U64, U64} = CallByName List.67 List.125 List.126 List.127;
+        ret List.679;
    else
-        let List.667 : {List U64, U64} = Struct {List.124, List.126};
-        ret List.667;
+        let List.677 : {List U64, U64} = Struct {List.125, List.127};
+        ret List.677;

 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.670 : {List U64, U64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.670;
+    let List.680 : {List U64, U64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.680;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.283 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/recursive_function_and_union_with_inference_hole.txt
+++ b/crates/compiler/test_mono/generated/recursive_function_and_union_with_inference_hole.txt
@ -1,52 +1,52 @@
-procedure List.100 (#Derived_gen.4, #Derived_gen.5, #Derived_gen.6, #Derived_gen.7, #Derived_gen.8):
-    joinpoint List.671 List.174 List.175 List.176 List.177 List.178:
-        let List.673 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.673 then
-            let List.677 : [<rnnu>C List *self] = CallByName List.66 List.174 List.177;
-            inc List.677;
-            let List.179 : List [<rnnu>C List *self] = CallByName List.283 List.175 List.677 List.176;
-            let List.676 : U64 = 1i64;
-            let List.675 : U64 = CallByName Num.51 List.177 List.676;
-            jump List.671 List.174 List.179 List.176 List.675 List.178;
+procedure List.101 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
+    joinpoint List.681 List.175 List.176 List.177 List.178 List.179:
+        let List.683 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.683 then
+            let List.687 : [<rnnu>C List *self] = CallByName List.66 List.175 List.178;
+            inc List.687;
+            let List.180 : List [<rnnu>C List *self] = CallByName List.284 List.176 List.687 List.177;
+            let List.686 : U64 = 1i64;
+            let List.685 : U64 = CallByName Num.51 List.178 List.686;
+            jump List.681 List.175 List.180 List.177 List.685 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.4;
-    jump List.671 #Derived_gen.4 #Derived_gen.5 #Derived_gen.6 #Derived_gen.7 #Derived_gen.8;
+    inc #Derived_gen.0;
+    jump List.681 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

-procedure List.18 (List.171, List.172, List.173):
-    let List.669 : U64 = 0i64;
-    let List.670 : U64 = CallByName List.6 List.171;
-    let List.668 : List [<rnnu>C List *self] = CallByName List.100 List.171 List.172 List.173 List.669 List.670;
-    ret List.668;
-
-procedure List.283 (List.284, List.285, List.281):
-    let List.682 : [<rnnu>C List *self] = CallByName Test.2 List.285;
-    let List.681 : List [<rnnu>C List *self] = CallByName List.71 List.284 List.682;
-    ret List.681;
-
-procedure List.5 (List.280, List.281):
-    let List.282 : U64 = CallByName List.6 List.280;
-    let List.666 : List [<rnnu>C List *self] = CallByName List.68 List.282;
-    let List.665 : List [<rnnu>C List *self] = CallByName List.18 List.280 List.666 List.281;
-    ret List.665;
-
-procedure List.6 (#Attr.2):
-    let List.679 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.679;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.678 : [<rnnu>C List *self] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.679 : U64 = 0i64;
+    let List.680 : U64 = CallByName List.6 List.172;
+    let List.678 : List [<rnnu>C List *self] = CallByName List.101 List.172 List.173 List.174 List.679 List.680;
    ret List.678;

+procedure List.284 (List.285, List.286, List.282):
+    let List.692 : [<rnnu>C List *self] = CallByName Test.2 List.286;
+    let List.691 : List [<rnnu>C List *self] = CallByName List.71 List.285 List.692;
+    ret List.691;
+
+procedure List.5 (List.281, List.282):
+    let List.283 : U64 = CallByName List.6 List.281;
+    let List.676 : List [<rnnu>C List *self] = CallByName List.68 List.283;
+    let List.675 : List [<rnnu>C List *self] = CallByName List.18 List.281 List.676 List.282;
+    ret List.675;
+
+procedure List.6 (#Attr.2):
+    let List.689 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.689;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.688 : [<rnnu>C List *self] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.688;
+
 procedure List.68 (#Attr.2):
-    let List.684 : List [<rnnu>C List *self] = lowlevel ListWithCapacity #Attr.2;
-    ret List.684;
+    let List.694 : List [<rnnu>C List *self] = lowlevel ListWithCapacity #Attr.2;
+    ret List.694;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.683 : List [<rnnu>C List *self] = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.683;
+    let List.693 : List [<rnnu>C List *self] = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.693;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.284 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/rigids.txt
+++ b/crates/compiler/test_mono/generated/rigids.txt
@ -1,41 +1,41 @@
-procedure List.2 (List.119, List.120):
-    let List.687 : U64 = CallByName List.6 List.119;
-    let List.684 : Int1 = CallByName Num.22 List.120 List.687;
-    if List.684 then
-        let List.686 : I64 = CallByName List.66 List.119 List.120;
-        let List.685 : [C {}, C I64] = TagId(1) List.686;
-        ret List.685;
+procedure List.2 (List.120, List.121):
+    let List.697 : U64 = CallByName List.6 List.120;
+    let List.694 : Int1 = CallByName Num.22 List.121 List.697;
+    if List.694 then
+        let List.696 : I64 = CallByName List.66 List.120 List.121;
+        let List.695 : [C {}, C I64] = TagId(1) List.696;
+        ret List.695;
    else
-        let List.683 : {} = Struct {};
-        let List.682 : [C {}, C I64] = TagId(0) List.683;
-        ret List.682;
+        let List.693 : {} = Struct {};
+        let List.692 : [C {}, C I64] = TagId(0) List.693;
+        ret List.692;

-procedure List.3 (List.127, List.128, List.129):
-    let List.674 : {List I64, I64} = CallByName List.64 List.127 List.128 List.129;
-    let List.673 : List I64 = StructAtIndex 0 List.674;
-    ret List.673;
+procedure List.3 (List.128, List.129, List.130):
+    let List.684 : {List I64, I64} = CallByName List.64 List.128 List.129 List.130;
+    let List.683 : List I64 = StructAtIndex 0 List.684;
+    ret List.683;

 procedure List.6 (#Attr.2):
-    let List.672 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.672;
+    let List.682 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.682;

-procedure List.64 (List.124, List.125, List.126):
-    let List.671 : U64 = CallByName List.6 List.124;
-    let List.668 : Int1 = CallByName Num.22 List.125 List.671;
-    if List.668 then
-        let List.669 : {List I64, I64} = CallByName List.67 List.124 List.125 List.126;
-        ret List.669;
+procedure List.64 (List.125, List.126, List.127):
+    let List.681 : U64 = CallByName List.6 List.125;
+    let List.678 : Int1 = CallByName Num.22 List.126 List.681;
+    if List.678 then
+        let List.679 : {List I64, I64} = CallByName List.67 List.125 List.126 List.127;
+        ret List.679;
    else
-        let List.667 : {List I64, I64} = Struct {List.124, List.126};
-        ret List.667;
+        let List.677 : {List I64, I64} = Struct {List.125, List.127};
+        ret List.677;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.680 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.680;
+    let List.690 : I64 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.690;

 procedure List.67 (#Attr.2, #Attr.3, #Attr.4):
-    let List.670 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
-    ret List.670;
+    let List.680 : {List I64, I64} = lowlevel ListReplaceUnsafe #Attr.2 #Attr.3 #Attr.4;
+    ret List.680;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.285 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/generated/unspecialized_lambda_set_unification_does_not_duplicate_identical_concrete_types.txt
+++ b/crates/compiler/test_mono/generated/unspecialized_lambda_set_unification_does_not_duplicate_identical_concrete_types.txt
@ -29,58 +29,58 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.6, #Derived_gen.7, #Derived_gen.8, #Derived_gen.9, #Derived_gen.10):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : Str = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.66 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.12, #Derived_gen.13, #Derived_gen.14, #Derived_gen.15, #Derived_gen.16):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : Str = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.66 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.6;
-    jump List.668 #Derived_gen.6 #Derived_gen.7 #Derived_gen.8 #Derived_gen.9 #Derived_gen.10;
+    inc #Derived_gen.12;
+    jump List.678 #Derived_gen.12 #Derived_gen.13 #Derived_gen.14 #Derived_gen.15 #Derived_gen.16;

 procedure List.13 (#Attr.2, #Attr.3):
-    let List.691 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
-    ret List.691;
+    let List.701 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
+    ret List.701;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.4 (List.135, List.136):
-    let List.687 : U64 = 1i64;
-    let List.686 : List U8 = CallByName List.70 List.135 List.687;
-    let List.685 : List U8 = CallByName List.71 List.686 List.136;
-    ret List.685;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

+procedure List.4 (List.136, List.137):
+    let List.697 : U64 = 1i64;
+    let List.696 : List U8 = CallByName List.70 List.136 List.697;
+    let List.695 : List U8 = CallByName List.71 List.696 List.137;
+    ret List.695;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.681 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.681;
+    let List.691 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.691;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.679 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.679;
+    let List.689 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.689;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.689 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.689;
+    let List.699 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.699;

 procedure Num.127 (#Attr.2):
    let Num.284 : U8 = lowlevel NumIntCast #Attr.2;
--- a/crates/compiler/test_mono/generated/unspecialized_lambda_set_unification_keeps_all_concrete_types_without_unification_of_unifiable.txt
+++ b/crates/compiler/test_mono/generated/unspecialized_lambda_set_unification_keeps_all_concrete_types_without_unification_of_unifiable.txt
@ -87,93 +87,93 @@ procedure Encode.26 (Encode.107, Encode.108):
    let Encode.110 : List U8 = CallByName Encode.24 Encode.111 Encode.112 Encode.108;
    ret Encode.110;

-procedure List.100 (#Derived_gen.29, #Derived_gen.30, #Derived_gen.31, #Derived_gen.32, #Derived_gen.33):
-    joinpoint List.695 List.174 List.175 List.176 List.177 List.178:
-        let List.697 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.697 then
-            let List.701 : Str = CallByName List.66 List.174 List.177;
-            inc List.701;
-            let List.179 : List U8 = CallByName Test.66 List.175 List.701 List.176;
-            let List.700 : U64 = 1i64;
-            let List.699 : U64 = CallByName Num.51 List.177 List.700;
-            jump List.695 List.174 List.179 List.176 List.699 List.178;
+procedure List.101 (#Derived_gen.26, #Derived_gen.27, #Derived_gen.28, #Derived_gen.29, #Derived_gen.30):
+    joinpoint List.678 List.175 List.176 List.177 List.178 List.179:
+        let List.680 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.680 then
+            let List.684 : [C {}, C {}, C Str] = CallByName List.66 List.175 List.178;
+            inc List.684;
+            let List.180 : List U8 = CallByName Test.66 List.176 List.684 List.177;
+            let List.683 : U64 = 1i64;
+            let List.682 : U64 = CallByName Num.51 List.178 List.683;
+            jump List.678 List.175 List.180 List.177 List.682 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
-    inc #Derived_gen.29;
-    jump List.695 #Derived_gen.29 #Derived_gen.30 #Derived_gen.31 #Derived_gen.32 #Derived_gen.33;
+    inc #Derived_gen.26;
+    jump List.678 #Derived_gen.26 #Derived_gen.27 #Derived_gen.28 #Derived_gen.29 #Derived_gen.30;

-procedure List.100 (#Derived_gen.49, #Derived_gen.50, #Derived_gen.51, #Derived_gen.52, #Derived_gen.53):
-    joinpoint List.668 List.174 List.175 List.176 List.177 List.178:
-        let List.670 : Int1 = CallByName Num.22 List.177 List.178;
-        if List.670 then
-            let List.674 : [C {}, C {}, C Str] = CallByName List.66 List.174 List.177;
-            inc List.674;
-            let List.179 : List U8 = CallByName Test.66 List.175 List.674 List.176;
-            let List.673 : U64 = 1i64;
-            let List.672 : U64 = CallByName Num.51 List.177 List.673;
-            jump List.668 List.174 List.179 List.176 List.672 List.178;
+procedure List.101 (#Derived_gen.49, #Derived_gen.50, #Derived_gen.51, #Derived_gen.52, #Derived_gen.53):
+    joinpoint List.705 List.175 List.176 List.177 List.178 List.179:
+        let List.707 : Int1 = CallByName Num.22 List.178 List.179;
+        if List.707 then
+            let List.711 : Str = CallByName List.66 List.175 List.178;
+            inc List.711;
+            let List.180 : List U8 = CallByName Test.66 List.176 List.711 List.177;
+            let List.710 : U64 = 1i64;
+            let List.709 : U64 = CallByName Num.51 List.178 List.710;
+            jump List.705 List.175 List.180 List.177 List.709 List.179;
        else
-            dec List.174;
-            ret List.175;
+            dec List.175;
+            ret List.176;
    in
    inc #Derived_gen.49;
-    jump List.668 #Derived_gen.49 #Derived_gen.50 #Derived_gen.51 #Derived_gen.52 #Derived_gen.53;
+    jump List.705 #Derived_gen.49 #Derived_gen.50 #Derived_gen.51 #Derived_gen.52 #Derived_gen.53;

 procedure List.13 (#Attr.2, #Attr.3):
-    let List.691 : List [C {}, C {}, C Str] = lowlevel ListPrepend #Attr.2 #Attr.3;
-    ret List.691;
+    let List.701 : List [C {}, C {}, C Str] = lowlevel ListPrepend #Attr.2 #Attr.3;
+    ret List.701;

 procedure List.13 (#Attr.2, #Attr.3):
-    let List.719 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
-    ret List.719;
+    let List.729 : List Str = lowlevel ListPrepend #Attr.2 #Attr.3;
+    ret List.729;

-procedure List.18 (List.171, List.172, List.173):
-    let List.666 : U64 = 0i64;
-    let List.667 : U64 = CallByName List.6 List.171;
-    let List.665 : List U8 = CallByName List.100 List.171 List.172 List.173 List.666 List.667;
-    ret List.665;
-
-procedure List.18 (List.171, List.172, List.173):
-    let List.693 : U64 = 0i64;
-    let List.694 : U64 = CallByName List.6 List.171;
-    let List.692 : List U8 = CallByName List.100 List.171 List.172 List.173 List.693 List.694;
-    ret List.692;
-
-procedure List.4 (List.135, List.136):
-    let List.714 : U64 = 1i64;
-    let List.713 : List U8 = CallByName List.70 List.135 List.714;
-    let List.712 : List U8 = CallByName List.71 List.713 List.136;
-    ret List.712;
-
-procedure List.6 (#Attr.2):
-    let List.690 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.690;
-
-procedure List.6 (#Attr.2):
-    let List.717 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.717;
-
-procedure List.66 (#Attr.2, #Attr.3):
-    let List.675 : [C {}, C {}, C Str] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.676 : U64 = 0i64;
+    let List.677 : U64 = CallByName List.6 List.172;
+    let List.675 : List U8 = CallByName List.101 List.172 List.173 List.174 List.676 List.677;
    ret List.675;

-procedure List.66 (#Attr.2, #Attr.3):
-    let List.702 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+procedure List.18 (List.172, List.173, List.174):
+    let List.703 : U64 = 0i64;
+    let List.704 : U64 = CallByName List.6 List.172;
+    let List.702 : List U8 = CallByName List.101 List.172 List.173 List.174 List.703 List.704;
    ret List.702;

+procedure List.4 (List.136, List.137):
+    let List.724 : U64 = 1i64;
+    let List.723 : List U8 = CallByName List.70 List.136 List.724;
+    let List.722 : List U8 = CallByName List.71 List.723 List.137;
+    ret List.722;
+
+procedure List.6 (#Attr.2):
+    let List.700 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.700;
+
+procedure List.6 (#Attr.2):
+    let List.727 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.727;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.685 : [C {}, C {}, C Str] = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.685;
+
+procedure List.66 (#Attr.2, #Attr.3):
+    let List.712 : Str = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.712;
+
 procedure List.70 (#Attr.2, #Attr.3):
-    let List.708 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
-    ret List.708;
+    let List.718 : List U8 = lowlevel ListReserve #Attr.2 #Attr.3;
+    ret List.718;

 procedure List.71 (#Attr.2, #Attr.3):
-    let List.706 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
-    ret List.706;
+    let List.716 : List U8 = lowlevel ListAppendUnsafe #Attr.2 #Attr.3;
+    ret List.716;

 procedure List.8 (#Attr.2, #Attr.3):
-    let List.716 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
-    ret List.716;
+    let List.726 : List U8 = lowlevel ListConcat #Attr.2 #Attr.3;
+    ret List.726;

 procedure Num.127 (#Attr.2):
    let Num.288 : U8 = lowlevel NumIntCast #Attr.2;
--- a/crates/compiler/test_mono/generated/weakening_avoids_overspecialization.txt
+++ b/crates/compiler/test_mono/generated/weakening_avoids_overspecialization.txt
@ -2,81 +2,81 @@ procedure Bool.11 (#Attr.2, #Attr.3):
    let Bool.23 : Int1 = lowlevel Eq #Attr.2 #Attr.3;
    ret Bool.23;

-procedure List.115 (List.562, List.563, List.564):
-    let List.683 : U64 = 0i64;
-    let List.684 : U64 = CallByName List.6 List.562;
-    let List.682 : [C U64, C U64] = CallByName List.80 List.562 List.563 List.564 List.683 List.684;
-    ret List.682;
+procedure List.116 (List.563, List.564, List.565):
+    let List.693 : U64 = 0i64;
+    let List.694 : U64 = CallByName List.6 List.563;
+    let List.692 : [C U64, C U64] = CallByName List.80 List.563 List.564 List.565 List.693 List.694;
+    ret List.692;

-procedure List.26 (List.212, List.213, List.214):
-    let List.676 : [C U64, C U64] = CallByName List.115 List.212 List.213 List.214;
-    let List.679 : U8 = 1i64;
-    let List.680 : U8 = GetTagId List.676;
-    let List.681 : Int1 = lowlevel Eq List.679 List.680;
-    if List.681 then
-        let List.215 : U64 = UnionAtIndex (Id 1) (Index 0) List.676;
-        ret List.215;
-    else
-        let List.216 : U64 = UnionAtIndex (Id 0) (Index 0) List.676;
+procedure List.26 (List.213, List.214, List.215):
+    let List.686 : [C U64, C U64] = CallByName List.116 List.213 List.214 List.215;
+    let List.689 : U8 = 1i64;
+    let List.690 : U8 = GetTagId List.686;
+    let List.691 : Int1 = lowlevel Eq List.689 List.690;
+    if List.691 then
+        let List.216 : U64 = UnionAtIndex (Id 1) (Index 0) List.686;
        ret List.216;
+    else
+        let List.217 : U64 = UnionAtIndex (Id 0) (Index 0) List.686;
+        ret List.217;

-procedure List.38 (List.400, List.401):
-    let List.675 : U64 = CallByName List.6 List.400;
-    let List.402 : U64 = CallByName Num.77 List.675 List.401;
-    let List.665 : List U8 = CallByName List.43 List.400 List.402;
-    ret List.665;
+procedure List.38 (List.401, List.402):
+    let List.685 : U64 = CallByName List.6 List.401;
+    let List.403 : U64 = CallByName Num.77 List.685 List.402;
+    let List.675 : List U8 = CallByName List.43 List.401 List.403;
+    ret List.675;

-procedure List.43 (List.398, List.399):
-    let List.673 : U64 = CallByName List.6 List.398;
-    let List.672 : U64 = CallByName Num.77 List.673 List.399;
-    let List.667 : {U64, U64} = Struct {List.399, List.672};
-    let List.666 : List U8 = CallByName List.49 List.398 List.667;
-    ret List.666;
+procedure List.43 (List.399, List.400):
+    let List.683 : U64 = CallByName List.6 List.399;
+    let List.682 : U64 = CallByName Num.77 List.683 List.400;
+    let List.677 : {U64, U64} = Struct {List.400, List.682};
+    let List.676 : List U8 = CallByName List.49 List.399 List.677;
+    ret List.676;

-procedure List.49 (List.476, List.477):
-    let List.669 : U64 = StructAtIndex 1 List.477;
-    let List.670 : U64 = StructAtIndex 0 List.477;
-    let List.668 : List U8 = CallByName List.72 List.476 List.669 List.670;
-    ret List.668;
+procedure List.49 (List.477, List.478):
+    let List.679 : U64 = StructAtIndex 1 List.478;
+    let List.680 : U64 = StructAtIndex 0 List.478;
+    let List.678 : List U8 = CallByName List.72 List.477 List.679 List.680;
+    ret List.678;

 procedure List.6 (#Attr.2):
-    let List.674 : U64 = lowlevel ListLenU64 #Attr.2;
-    ret List.674;
+    let List.684 : U64 = lowlevel ListLenU64 #Attr.2;
+    ret List.684;

 procedure List.66 (#Attr.2, #Attr.3):
-    let List.697 : U8 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
-    ret List.697;
+    let List.707 : U8 = lowlevel ListGetUnsafe #Attr.2 #Attr.3;
+    ret List.707;

 procedure List.72 (#Attr.2, #Attr.3, #Attr.4):
-    let List.671 : List U8 = lowlevel ListSublist #Attr.2 #Attr.3 #Attr.4;
-    ret List.671;
+    let List.681 : List U8 = lowlevel ListSublist #Attr.2 #Attr.3 #Attr.4;
+    ret List.681;

 procedure List.80 (#Derived_gen.0, #Derived_gen.1, #Derived_gen.2, #Derived_gen.3, #Derived_gen.4):
-    joinpoint List.685 List.565 List.566 List.567 List.568 List.569:
-        let List.687 : Int1 = CallByName Num.22 List.568 List.569;
-        if List.687 then
-            let List.696 : U8 = CallByName List.66 List.565 List.568;
-            let List.688 : [C U64, C U64] = CallByName Test.3 List.566 List.696;
-            let List.693 : U8 = 1i64;
-            let List.694 : U8 = GetTagId List.688;
-            let List.695 : Int1 = lowlevel Eq List.693 List.694;
-            if List.695 then
-                let List.570 : U64 = UnionAtIndex (Id 1) (Index 0) List.688;
-                let List.691 : U64 = 1i64;
-                let List.690 : U64 = CallByName Num.51 List.568 List.691;
-                jump List.685 List.565 List.570 List.567 List.690 List.569;
+    joinpoint List.695 List.566 List.567 List.568 List.569 List.570:
+        let List.697 : Int1 = CallByName Num.22 List.569 List.570;
+        if List.697 then
+            let List.706 : U8 = CallByName List.66 List.566 List.569;
+            let List.698 : [C U64, C U64] = CallByName Test.3 List.567 List.706;
+            let List.703 : U8 = 1i64;
+            let List.704 : U8 = GetTagId List.698;
+            let List.705 : Int1 = lowlevel Eq List.703 List.704;
+            if List.705 then
+                let List.571 : U64 = UnionAtIndex (Id 1) (Index 0) List.698;
+                let List.701 : U64 = 1i64;
+                let List.700 : U64 = CallByName Num.51 List.569 List.701;
+                jump List.695 List.566 List.571 List.568 List.700 List.570;
            else
-                dec List.565;
-                let List.571 : U64 = UnionAtIndex (Id 0) (Index 0) List.688;
-                let List.692 : [C U64, C U64] = TagId(0) List.571;
-                ret List.692;
+                dec List.566;
+                let List.572 : U64 = UnionAtIndex (Id 0) (Index 0) List.698;
+                let List.702 : [C U64, C U64] = TagId(0) List.572;
+                ret List.702;
        else
-            dec List.565;
-            let List.686 : [C U64, C U64] = TagId(1) List.566;
-            ret List.686;
+            dec List.566;
+            let List.696 : [C U64, C U64] = TagId(1) List.567;
+            ret List.696;
    in
    inc #Derived_gen.0;
-    jump List.685 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;
+    jump List.695 #Derived_gen.0 #Derived_gen.1 #Derived_gen.2 #Derived_gen.3 #Derived_gen.4;

 procedure Num.22 (#Attr.2, #Attr.3):
    let Num.286 : Int1 = lowlevel NumLt #Attr.2 #Attr.3;
--- a/crates/compiler/test_mono/src/tests.rs
+++ b/crates/compiler/test_mono/src/tests.rs
@ -1759,7 +1759,7 @@ fn lambda_capture_niches_with_other_lambda_capture() {
                when val is
                    _ -> ""

-        capture2 = \val -> \{} -> "$(val)"
+        capture2 = \val -> \{} -> "${val}"

        x : [A, B, C]
        x = A
@ -2072,7 +2072,7 @@ fn polymorphic_expression_unification() {
        ]
        parse_function : Str -> RenderTree
        parse_function = \name ->
-            last = Indent [Text ".trace(\"$(name)\")" ]
+            last = Indent [Text ".trace(\"${name}\")" ]
            Indent [last]

        values = parse_function "interface_header"
@ -2636,7 +2636,7 @@ fn recursively_build_effect() {
            hi = "Hello"
            name = "World"

-            "$(hi), $(name)!"
+            "${hi}, ${name}!"

        main =
            when nest_help 4 is
@ -2956,8 +2956,8 @@ fn compose_recursive_lambda_set_productive_nullable_wrapped() {
            else \x -> f (g x)

         identity = \x -> x
-         exclaim = \s -> "$(s)!"
-         whisper = \s -> "($(s))"
+         exclaim = \s -> "${s}!"
+         whisper = \s -> "(${s})"

         main =
             res: Str -> Str
@ -3291,7 +3291,7 @@ fn dbg_nested_expr() {
 fn dbg_inside_string() {
    indoc!(
        r#"
-        "Hello $(dbg "world")!"
+        "Hello ${dbg "world"}!"
        "#
    )
 }
@ -3690,7 +3690,7 @@ fn dec_refcount_for_usage_after_early_return_in_if() {
                    else
                        third

-            "$(first), $(second)"
+            "${first}, ${second}"

        display_n 3
        "#
--- a/crates/compiler/test_syntax/tests/snapshots/pass/block_string_ann.expr.formatted.roc
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/block_string_ann.expr.formatted.roc
@ -1,2 +1,2 @@
-"$(g)" : q
+"${g}" : q
 f
--- a/crates/compiler/test_syntax/tests/snapshots/pass/block_string_ann.expr.roc
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/block_string_ann.expr.roc
@ -1,2 +1,2 @@
-"""$(g)""":q
+"""${g}""":q
 f
--- a/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_a_over_a.expr.formatted.roc
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_a_over_a.expr.formatted.roc
@ -0,0 +1,2 @@
+dbg (a / a)
+d
--- a/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_a_over_a.expr.result-ast
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_a_over_a.expr.result-ast
@ -0,0 +1,32 @@
+@0-8 SpaceAfter(
+    DbgStmt {
+        first: @4-7 BinOps(
+            [
+                (
+                    @4-5 Var {
+                        module_name: "",
+                        ident: "a",
+                    },
+                    @5-6 Slash,
+                ),
+            ],
+            @6-7 Var {
+                module_name: "",
+                ident: "a",
+            },
+        ),
+        extra_args: [],
+        continuation: @9-10 SpaceBefore(
+            Var {
+                module_name: "",
+                ident: "d",
+            },
+            [
+                Newline,
+            ],
+        ),
+    },
+    [
+        Newline,
+    ],
+)
--- a/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_a_over_a.expr.roc
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_a_over_a.expr.roc
@ -0,0 +1,2 @@
+dbg(a/a)
+d
--- a/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_zero_args.expr.formatted.roc
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_zero_args.expr.formatted.roc
@ -0,0 +1,2 @@
+dbg()
+d
--- a/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_zero_args.expr.result-ast
+++ b/crates/compiler/test_syntax/tests/snapshots/pass/dbg_pnc_zero_args.expr.result-ast
@ -0,0 +1,40 @@
+@0-7 SpaceAfter(
+    Defs(
+        Defs {
+            tags: [
+                EitherIndex(2147483648),
+            ],
+            regions: [
+                @0-5,
+            ],
+            space_before: [
+                Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 0 },
+            ],
+            space_after: [
+                Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 0 },
+            ],
+            spaces: [],
+            type_defs: [],
+            value_defs: [
+                Stmt(
+                    @0-5 PncApply(
+                        @0-3 Dbg,
+                        [],
+                    ),
+                ),
+            ],
+        },
+        @6-7 SpaceBefore(
+            Var {
+                module_name: "",
+                ident: "d",
+            },
+            [
+                Newline,
+            ],
+        ),
+    ),
+    [
+        Newline,
+    ],
+)
--- a/Show more
+++ b/Show more