Merge remote-tracking branch 'origin/trunk' into fix-lambda-set-debug-instance

AUTHORS

@@ -61,3 +61,4 @@ Shahn Hogan <shahnhogan@hotmail.com>
 Tankor Smash <tankorsmash+github@gmail.com>
 Matthias Devlamynck <matthias.devlamynck@mailoo.org>
 Jan Van Bruggen <JanCVanB@users.noreply.github.com>
+Mats Sigge <<mats.sigge@gmail.com>>

Cargo.lock

@@ -3248,12 +3248,12 @@ dependencies = [
  "roc_builtins",
  "roc_can",
  "roc_collections",
+ "roc_error_macros",
  "roc_load",
  "roc_module",
  "roc_parse",
  "roc_problem",
  "roc_region",
- "roc_reporting",
  "roc_types",
  "roc_unify",
  "snafu",
@@ -3338,6 +3338,7 @@ dependencies = [
  "roc_constrain",
  "roc_docs",
  "roc_editor",
+ "roc_error_macros",
  "roc_fmt",
  "roc_gen_llvm",
  "roc_linker",
@@ -3470,6 +3471,10 @@ dependencies = [
  "winit",
 ]
 
+[[package]]
+name = "roc_error_macros"
+version = "0.1.0"
+
 [[package]]
 name = "roc_fmt"
 version = "0.1.0"
@@ -3495,12 +3500,12 @@ dependencies = [
  "roc_builtins",
  "roc_can",
  "roc_collections",
+ "roc_error_macros",
  "roc_module",
  "roc_mono",
  "roc_parse",
  "roc_problem",
  "roc_region",
- "roc_reporting",
  "roc_solve",
  "roc_std",
  "roc_types",
@@ -3517,9 +3522,9 @@ dependencies = [
  "morphic_lib",
  "roc_builtins",
  "roc_collections",
+ "roc_error_macros",
  "roc_module",
  "roc_mono",
- "roc_reporting",
  "roc_std",
  "target-lexicon",
 ]
@@ -3531,9 +3536,9 @@ dependencies = [
  "bumpalo",
  "roc_builtins",
  "roc_collections",
+ "roc_error_macros",
  "roc_module",
  "roc_mono",
- "roc_reporting",
  "roc_std",
 ]
 

Cargo.toml

@@ -30,6 +30,7 @@ members = [
     "ast",
     "cli",
     "code_markup",
+    "error_macros",
     "reporting",
     "roc_std",
     "test_utils",

Earthfile

@@ -47,7 +47,7 @@ install-zig-llvm-valgrind-clippy-rustfmt:
 
 copy-dirs:
     FROM +install-zig-llvm-valgrind-clippy-rustfmt
-    COPY --dir cli cli_utils compiler docs editor ast code_markup utils test_utils reporting roc_std vendor examples linker Cargo.toml Cargo.lock version.txt ./
+    COPY --dir cli cli_utils compiler docs editor ast code_markup error_macros utils test_utils reporting roc_std vendor examples linker Cargo.toml Cargo.lock version.txt ./
 
 test-zig:
     FROM +install-zig-llvm-valgrind-clippy-rustfmt

ast/Cargo.toml

@@ -17,7 +17,7 @@ roc_problem = { path = "../compiler/problem" }
 roc_types = { path = "../compiler/types" }
 roc_unify = { path = "../compiler/unify"}
 roc_load = { path = "../compiler/load" }
-roc_reporting = { path = "../reporting" }
+roc_error_macros = { path = "../error_macros" }
 arrayvec = "0.7.2"
 bumpalo = { version = "3.8.0", features = ["collections"] }
 libc = "0.2.106"

ast/src/lang/core/str.rs

@@ -1,6 +1,6 @@
+use roc_error_macros::internal_error;
 use roc_module::{called_via::CalledVia, symbol::Symbol};
 use roc_parse::ast::StrLiteral;
-use roc_reporting::internal_error;
 
 use crate::{
     ast_error::{ASTResult, UnexpectedASTNode},

cli/Cargo.toml

@@ -62,6 +62,7 @@ roc_gen_llvm = { path = "../compiler/gen_llvm", optional = true }
 roc_build = { path = "../compiler/build", default-features = false }
 roc_fmt = { path = "../compiler/fmt" }
 roc_reporting = { path = "../reporting" }
+roc_error_macros = { path = "../error_macros" }
 roc_editor = { path = "../editor", optional = true }
 roc_linker = { path = "../linker" }
 clap = { version = "= 3.0.0-beta.5", default-features = false, features = ["std", "color", "suggestions"] }

cli/src/format.rs

@@ -2,6 +2,7 @@ use std::path::PathBuf;
 
 use bumpalo::collections::Vec;
 use bumpalo::Bump;
+use roc_error_macros::{internal_error, user_error};
 use roc_fmt::def::fmt_def;
 use roc_fmt::module::fmt_module;
 use roc_fmt::Buf;
@@ -21,7 +22,6 @@ use roc_parse::{
     state::State,
 };
 use roc_region::all::{Loc, Region};
-use roc_reporting::{internal_error, user_error};
 
 pub fn format(files: std::vec::Vec<PathBuf>) {
     for file in files {

cli/src/repl.rs

@@ -1,7 +1,7 @@
 use const_format::concatcp;
 #[cfg(feature = "llvm")]
 use gen::{gen_and_eval, ReplOutput};
-use roc_parse::parser::{EExpr, SyntaxError};
+use roc_parse::parser::{EExpr, ELambda, SyntaxError};
 use rustyline::highlight::{Highlighter, PromptInfo};
 use rustyline::validate::{self, ValidationContext, ValidationResult, Validator};
 use rustyline_derive::{Completer, Helper, Hinter};
@@ -97,7 +97,8 @@ impl Validator for InputValidator {
             match roc_parse::expr::parse_loc_expr(0, &arena, state) {
                 // Special case some syntax errors to allow for multi-line inputs
                 Err((_, EExpr::DefMissingFinalExpr(_), _))
-                | Err((_, EExpr::DefMissingFinalExpr2(_, _), _)) => {
+                | Err((_, EExpr::DefMissingFinalExpr2(_, _), _))
+                | Err((_, EExpr::Lambda(ELambda::Body(_, _), _), _)) => {
                     Ok(ValidationResult::Incomplete)
                 }
                 _ => Ok(ValidationResult::Valid(None)),

cli/tests/repl_eval.rs

@@ -925,4 +925,38 @@ mod repl_eval {
             ),
         );
     }
+
+    #[test]
+    fn issue_2343_complete_mono_with_shadowed_vars() {
+        expect_failure(
+            indoc!(
+                r#"
+                b = False
+                f = \b ->
+                    when b is
+                        True -> 5
+                        False -> 15
+                f b
+                "#
+            ),
+            indoc!(
+                r#"
+                ── DUPLICATE NAME ──────────────────────────────────────────────────────────────
+
+                The b name is first defined here:
+
+                4│      b = False
+                        ^
+
+                But then it's defined a second time here:
+
+                5│      f = \b ->
+                             ^
+
+                Since these variables have the same name, it's easy to use the wrong
+                one on accident. Give one of them a new name.
+                "#
+            ),
+        );
+    }
 }

compiler/builtins/docs/List.roc

@@ -32,6 +32,8 @@ interface List
             set,
             single,
             sortWith,
+            split,
+            sublist,
             sum,
             swap,
             walk,
@@ -205,7 +207,7 @@ empty : List *
 ## Returns a list with the given length, where every element is the given value.
 ##
 ##
-repeat : elem, Nat -> List elem
+repeat : Nat, elem -> List elem
 
 ## Returns a list of all the integers between one and another,
 ## including both of the given numbers.
@@ -277,7 +279,7 @@ map4 : List a, List b, List c, List d, (a, b, c, d -> e) -> List e
 
 ## This works like [List.map], except it also passes the index
 ## of the element to the conversion function.
-mapWithIndex : List before, (before, Nat -> after) -> List after
+mapWithIndex : List before, (Nat, before -> after) -> List after
 
 ## This works like [List.map], except at any time you can return `Err` to
 ## cancel the entire operation immediately, and return that #Err.

compiler/can/src/annotation.rs

@@ -390,7 +390,7 @@ fn can_annotation_help(
             ) {
                 Ok(symbol) => symbol,
 
-                Err((original_region, shadow)) => {
+                Err((original_region, shadow, _new_symbol)) => {
                     let problem = Problem::Shadowed(original_region, shadow.clone());
 
                     env.problem(roc_problem::can::Problem::ShadowingInAnnotation {

compiler/can/src/def.rs

@@ -809,7 +809,7 @@ fn pattern_to_vars_by_symbol(
 ) {
     use Pattern::*;
     match pattern {
-        Identifier(symbol) => {
+        Identifier(symbol) | Shadowed(_, _, symbol) => {
             vars_by_symbol.insert(*symbol, expr_var);
         }
 
@@ -832,8 +832,6 @@ fn pattern_to_vars_by_symbol(
         | Underscore
         | MalformedPattern(_, _)
         | UnsupportedPattern(_) => {}
-
-        Shadowed(_, _) => {}
     }
 }
 
@@ -884,7 +882,7 @@ fn canonicalize_pending_def<'a>(
                 Pattern::Identifier(symbol) => RuntimeError::NoImplementationNamed {
                     def_symbol: *symbol,
                 },
-                Pattern::Shadowed(region, loc_ident) => RuntimeError::Shadowing {
+                Pattern::Shadowed(region, loc_ident, _new_symbol) => RuntimeError::Shadowing {
                     original_region: *region,
                     shadow: loc_ident.clone(),
                 },
@@ -1502,7 +1500,7 @@ fn to_pending_def<'a>(
                     ))
                 }
 
-                Err((original_region, loc_shadowed_symbol)) => {
+                Err((original_region, loc_shadowed_symbol, _new_symbol)) => {
                     env.problem(Problem::ShadowingInAnnotation {
                         original_region,
                         shadow: loc_shadowed_symbol,

compiler/can/src/module.rs

@@ -398,7 +398,7 @@ fn fix_values_captured_in_closure_pattern(
         | FloatLiteral(_, _, _)
         | StrLiteral(_)
         | Underscore
-        | Shadowed(_, _)
+        | Shadowed(..)
         | MalformedPattern(_, _)
         | UnsupportedPattern(_) => (),
     }

compiler/can/src/pattern.rs

@@ -32,7 +32,7 @@ pub enum Pattern {
     Underscore,
 
     // Runtime Exceptions
-    Shadowed(Region, Loc<Ident>),
+    Shadowed(Region, Loc<Ident>, Symbol),
     // Example: (5 = 1 + 2) is an unsupported pattern in an assignment; Int patterns aren't allowed in assignments!
     UnsupportedPattern(Region),
     // parse error patterns
@@ -65,7 +65,7 @@ pub fn symbols_from_pattern_help(pattern: &Pattern, symbols: &mut Vec<Symbol>) {
     use Pattern::*;
 
     match pattern {
-        Identifier(symbol) => {
+        Identifier(symbol) | Shadowed(_, _, symbol) => {
             symbols.push(*symbol);
         }
 
@@ -92,8 +92,6 @@ pub fn symbols_from_pattern_help(pattern: &Pattern, symbols: &mut Vec<Symbol>) {
         | Underscore
         | MalformedPattern(_, _)
         | UnsupportedPattern(_) => {}
-
-        Shadowed(_, _) => {}
     }
 }
 
@@ -121,13 +119,14 @@ pub fn canonicalize_pattern<'a>(
 
                 Pattern::Identifier(symbol)
             }
-            Err((original_region, shadow)) => {
+            Err((original_region, shadow, new_symbol)) => {
                 env.problem(Problem::RuntimeError(RuntimeError::Shadowing {
                     original_region,
                     shadow: shadow.clone(),
                 }));
+                output.references.bound_symbols.insert(new_symbol);
 
-                Pattern::Shadowed(original_region, shadow)
+                Pattern::Shadowed(original_region, shadow, new_symbol)
             }
         },
         GlobalTag(name) => {
@@ -268,7 +267,7 @@ pub fn canonicalize_pattern<'a>(
                                     },
                                 });
                             }
-                            Err((original_region, shadow)) => {
+                            Err((original_region, shadow, new_symbol)) => {
                                 env.problem(Problem::RuntimeError(RuntimeError::Shadowing {
                                     original_region,
                                     shadow: shadow.clone(),
@@ -278,7 +277,8 @@ pub fn canonicalize_pattern<'a>(
                                 // are, we're definitely shadowed and will
                                 // get a runtime exception as soon as we
                                 // encounter the first bad pattern.
-                                opt_erroneous = Some(Pattern::Shadowed(original_region, shadow));
+                                opt_erroneous =
+                                    Some(Pattern::Shadowed(original_region, shadow, new_symbol));
                             }
                         };
                     }
@@ -339,7 +339,7 @@ pub fn canonicalize_pattern<'a>(
                                     },
                                 });
                             }
-                            Err((original_region, shadow)) => {
+                            Err((original_region, shadow, new_symbol)) => {
                                 env.problem(Problem::RuntimeError(RuntimeError::Shadowing {
                                     original_region,
                                     shadow: shadow.clone(),
@@ -349,7 +349,8 @@ pub fn canonicalize_pattern<'a>(
                                 // are, we're definitely shadowed and will
                                 // get a runtime exception as soon as we
                                 // encounter the first bad pattern.
-                                opt_erroneous = Some(Pattern::Shadowed(original_region, shadow));
+                                opt_erroneous =
+                                    Some(Pattern::Shadowed(original_region, shadow, new_symbol));
                             }
                         };
                     }
@@ -452,7 +453,7 @@ fn add_bindings_from_patterns(
     use Pattern::*;
 
     match pattern {
-        Identifier(symbol) => {
+        Identifier(symbol) | Shadowed(_, _, symbol) => {
             answer.push((*symbol, *region));
         }
         AppliedTag {
@@ -477,7 +478,6 @@ fn add_bindings_from_patterns(
         | FloatLiteral(_, _, _)
         | StrLiteral(_)
         | Underscore
-        | Shadowed(_, _)
         | MalformedPattern(_, _)
         | UnsupportedPattern(_) => (),
     }

compiler/can/src/scope.rs

@@ -110,15 +110,21 @@ impl Scope {
         exposed_ident_ids: &IdentIds,
         all_ident_ids: &mut IdentIds,
         region: Region,
-    ) -> Result<Symbol, (Region, Loc<Ident>)> {
+    ) -> Result<Symbol, (Region, Loc<Ident>, Symbol)> {
         match self.idents.get(&ident) {
-            Some((_, original_region)) => {
+            Some(&(_, original_region)) => {
                 let shadow = Loc {
-                    value: ident,
+                    value: ident.clone(),
                     region,
                 };
 
-                Err((*original_region, shadow))
+                let ident_id = all_ident_ids.add(ident.clone());
+                let symbol = Symbol::new(self.home, ident_id);
+
+                self.symbols.insert(symbol, region);
+                self.idents.insert(ident, (symbol, region));
+
+                Err((original_region, shadow, symbol))
             }
             None => {
                 // If this IdentId was already added previously

compiler/can/tests/test_can.rs

@@ -368,9 +368,11 @@ mod test_can {
         let arena = Bump::new();
         let CanExprOut { problems, .. } = can_expr_with(&arena, test_home(), src);
 
-        assert_eq!(problems.len(), 1);
+        assert_eq!(problems.len(), 2);
         assert!(problems.iter().all(|problem| match problem {
             Problem::RuntimeError(RuntimeError::Shadowing { .. }) => true,
+            // Due to one of the shadows
+            Problem::UnusedDef(..) => true,
             _ => false,
         }));
     }
@@ -389,9 +391,11 @@ mod test_can {
         let arena = Bump::new();
         let CanExprOut { problems, .. } = can_expr_with(&arena, test_home(), src);
 
-        assert_eq!(problems.len(), 1);
+        assert_eq!(problems.len(), 2);
         assert!(problems.iter().all(|problem| match problem {
             Problem::RuntimeError(RuntimeError::Shadowing { .. }) => true,
+            // Due to one of the shadows
+            Problem::UnusedDef(..) => true,
             _ => false,
         }));
     }
@@ -410,10 +414,12 @@ mod test_can {
         let arena = Bump::new();
         let CanExprOut { problems, .. } = can_expr_with(&arena, test_home(), src);
 
-        assert_eq!(problems.len(), 1);
+        assert_eq!(problems.len(), 2);
         println!("{:#?}", problems);
         assert!(problems.iter().all(|problem| match problem {
             Problem::RuntimeError(RuntimeError::Shadowing { .. }) => true,
+            // Due to one of the shadows
+            Problem::UnusedDef(..) => true,
             _ => false,
         }));
     }

compiler/constrain/src/pattern.rs

@@ -48,12 +48,11 @@ fn headers_from_annotation_help(
     headers: &mut SendMap<Symbol, Loc<Type>>,
 ) -> bool {
     match pattern {
-        Identifier(symbol) => {
+        Identifier(symbol) | Shadowed(_, _, symbol) => {
             headers.insert(*symbol, annotation.clone());
             true
         }
         Underscore
-        | Shadowed(_, _)
         | MalformedPattern(_, _)
         | UnsupportedPattern(_)
         | NumLiteral(_, _, _)
@@ -159,11 +158,11 @@ pub fn constrain_pattern(
                 PresenceConstraint::IsOpen,
             ));
         }
-        Underscore | UnsupportedPattern(_) | MalformedPattern(_, _) | Shadowed(_, _) => {
+        Underscore | UnsupportedPattern(_) | MalformedPattern(_, _) => {
             // Neither the _ pattern nor erroneous ones add any constraints.
         }
 
-        Identifier(symbol) => {
+        Identifier(symbol) | Shadowed(_, _, symbol) => {
             if destruct_position {
                 state.constraints.push(Constraint::Present(
                     expected.get_type_ref().clone(),

compiler/gen_dev/Cargo.toml

@@ -16,7 +16,7 @@ roc_builtins = { path = "../builtins" }
 roc_unify = { path = "../unify" }
 roc_solve = { path = "../solve" }
 roc_mono = { path = "../mono" }
-roc_reporting = { path = "../../reporting" }
+roc_error_macros = { path = "../../error_macros" }
 bumpalo = { version = "3.8.0", features = ["collections"] }
 target-lexicon = "0.12.2"
 # TODO: Deal with the update of object to 0.27.

compiler/gen_dev/src/generic64/aarch64.rs

@@ -3,9 +3,9 @@ use crate::Relocation;
 use bumpalo::collections::Vec;
 use packed_struct::prelude::*;
 use roc_collections::all::MutMap;
+use roc_error_macros::internal_error;
 use roc_module::symbol::Symbol;
 use roc_mono::layout::Layout;
-use roc_reporting::internal_error;
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)]
 #[allow(dead_code)]

compiler/gen_dev/src/generic64/mod.rs

@@ -2,11 +2,11 @@ use crate::{Backend, Env, Relocation};
 use bumpalo::collections::Vec;
 use roc_builtins::bitcode::{FloatWidth, IntWidth};
 use roc_collections::all::{MutMap, MutSet};
+use roc_error_macros::internal_error;
 use roc_module::symbol::{Interns, Symbol};
 use roc_mono::code_gen_help::CodeGenHelp;
 use roc_mono::ir::{BranchInfo, JoinPointId, Literal, Param, ProcLayout, SelfRecursive, Stmt};
 use roc_mono::layout::{Builtin, Layout};
-use roc_reporting::internal_error;
 use std::marker::PhantomData;
 
 pub mod aarch64;

compiler/gen_dev/src/generic64/x86_64.rs

@@ -5,9 +5,9 @@ use crate::{
 use bumpalo::collections::Vec;
 use roc_builtins::bitcode::{FloatWidth, IntWidth};
 use roc_collections::all::MutMap;
+use roc_error_macros::internal_error;
 use roc_module::symbol::Symbol;
 use roc_mono::layout::{Builtin, Layout};
-use roc_reporting::internal_error;
 
 // Not sure exactly how I want to represent registers.
 // If we want max speed, we would likely make them structs that impl the same trait to avoid ifs.

compiler/gen_dev/src/lib.rs

@@ -5,6 +5,7 @@
 use bumpalo::{collections::Vec, Bump};
 use roc_builtins::bitcode::{self, FloatWidth, IntWidth};
 use roc_collections::all::{MutMap, MutSet};
+use roc_error_macros::internal_error;
 use roc_module::ident::{ModuleName, TagName};
 use roc_module::low_level::{LowLevel, LowLevelWrapperType};
 use roc_module::symbol::{Interns, ModuleId, Symbol};
@@ -14,7 +15,6 @@ use roc_mono::ir::{
     SelfRecursive, Stmt,
 };
 use roc_mono::layout::{Builtin, Layout, LayoutId, LayoutIds};
-use roc_reporting::internal_error;
 
 mod generic64;
 mod object_builder;

compiler/gen_dev/src/object_builder.rs

@@ -8,11 +8,11 @@ use object::{
     SymbolFlags, SymbolKind, SymbolScope,
 };
 use roc_collections::all::MutMap;
+use roc_error_macros::internal_error;
 use roc_module::symbol;
 use roc_module::symbol::Interns;
 use roc_mono::ir::{Proc, ProcLayout};
 use roc_mono::layout::LayoutIds;
-use roc_reporting::internal_error;
 use target_lexicon::{Architecture as TargetArch, BinaryFormat as TargetBF, Triple};
 
 // This is used by some code below which is currently commented out.

compiler/gen_llvm/Cargo.toml

@@ -10,7 +10,7 @@ edition = "2018"
 roc_collections = { path = "../collections" }
 roc_module = { path = "../module" }
 roc_builtins = { path = "../builtins" }
-roc_reporting = { path = "../../reporting" }
+roc_error_macros = { path = "../../error_macros" }
 roc_mono = { path = "../mono" }
 roc_std = { path = "../../roc_std" }
 morphic_lib = { path = "../../vendor/morphic_lib" }

compiler/gen_llvm/src/llvm/build.rs

@@ -55,6 +55,7 @@ use morphic_lib::{
 use roc_builtins::bitcode::{self, FloatWidth, IntWidth, IntrinsicName};
 use roc_builtins::{float_intrinsic, int_intrinsic};
 use roc_collections::all::{ImMap, MutMap, MutSet};
+use roc_error_macros::internal_error;
 use roc_module::low_level::LowLevel;
 use roc_module::symbol::{Interns, ModuleId, Symbol};
 use roc_mono::ir::{
@@ -62,7 +63,6 @@ use roc_mono::ir::{
     ModifyRc, OptLevel, ProcLayout,
 };
 use roc_mono::layout::{Builtin, LambdaSet, Layout, LayoutIds, TagIdIntType, UnionLayout};
-use roc_reporting::internal_error;
 use target_lexicon::{Architecture, OperatingSystem, Triple};
 
 /// This is for Inkwell's FunctionValue::verify - we want to know the verification

compiler/gen_wasm/Cargo.toml

@@ -12,4 +12,4 @@ roc_collections = { path = "../collections" }
 roc_module = { path = "../module" }
 roc_mono = { path = "../mono" }
 roc_std = { path = "../../roc_std" }
-roc_reporting = { path = "../../reporting" }
+roc_error_macros = { path = "../../error_macros" }

compiler/gen_wasm/src/backend.rs

@@ -12,8 +12,8 @@ use roc_mono::ir::{
     ProcLayout, Stmt,
 };
 
+use roc_error_macros::internal_error;
 use roc_mono::layout::{Builtin, Layout, LayoutIds, TagIdIntType, UnionLayout};
-use roc_reporting::internal_error;
 
 use crate::layout::{CallConv, ReturnMethod, WasmLayout};
 use crate::low_level::LowLevelCall;

compiler/gen_wasm/src/low_level.rs

@@ -1,9 +1,9 @@
 use bumpalo::collections::Vec;
 use roc_builtins::bitcode::{self, FloatWidth, IntWidth};
+use roc_error_macros::internal_error;
 use roc_module::low_level::{LowLevel, LowLevel::*};
 use roc_module::symbol::Symbol;
 use roc_mono::layout::{Builtin, Layout, UnionLayout};
-use roc_reporting::internal_error;
 
 use crate::backend::WasmBackend;
 use crate::layout::CallConv;

compiler/gen_wasm/src/storage.rs

@@ -2,9 +2,9 @@ use bumpalo::collections::Vec;
 use bumpalo::Bump;
 
 use roc_collections::all::MutMap;
+use roc_error_macros::internal_error;
 use roc_module::symbol::Symbol;
 use roc_mono::layout::Layout;
-use roc_reporting::internal_error;
 
 use crate::layout::{
     CallConv, ReturnMethod, StackMemoryFormat, WasmLayout, ZigVersion, BUILTINS_ZIG_VERSION,

compiler/gen_wasm/src/wasm_module/code_builder.rs

@@ -1,7 +1,7 @@
 use bumpalo::collections::vec::Vec;
 use bumpalo::Bump;
 use core::panic;
-use roc_reporting::internal_error;
+use roc_error_macros::internal_error;
 
 use roc_module::symbol::Symbol;
 

compiler/gen_wasm/src/wasm_module/mod.rs

@@ -8,7 +8,7 @@ pub mod serialize;
 use bumpalo::Bump;
 pub use code_builder::{Align, CodeBuilder, LocalId, ValueType, VmSymbolState};
 pub use linking::SymInfo;
-use roc_reporting::internal_error;
+use roc_error_macros::internal_error;
 pub use sections::{ConstExpr, Export, ExportType, Global, GlobalType, Signature};
 
 use crate::wasm_module::serialize::SkipBytes;

compiler/gen_wasm/src/wasm_module/opcodes.rs

@@ -1,4 +1,4 @@
-use roc_reporting::internal_error;
+use roc_error_macros::internal_error;
 
 use super::serialize::{parse_u32_or_panic, SkipBytes};
 

compiler/gen_wasm/src/wasm_module/sections.rs

@@ -1,7 +1,7 @@
 use bumpalo::collections::vec::Vec;
 use bumpalo::Bump;
 use roc_collections::all::MutMap;
-use roc_reporting::internal_error;
+use roc_error_macros::internal_error;
 
 use super::dead_code::{
     copy_preloads_shrinking_dead_fns, parse_preloads_call_graph, trace_call_graph,

compiler/gen_wasm/src/wasm_module/serialize.rs

@@ -1,7 +1,7 @@
 use std::{fmt::Debug, iter::FromIterator};
 
 use bumpalo::collections::vec::Vec;
-use roc_reporting::internal_error;
+use roc_error_macros::internal_error;
 
 /// In the WebAssembly binary format, all integers are variable-length encoded (using LEB-128)
 /// A small value like 3 or 100 is encoded as 1 byte. The value 128 needs 2 bytes, etc.

compiler/mono/src/ir.rs

@@ -1980,12 +1980,12 @@ fn pattern_to_when<'a>(
             // for underscore we generate a dummy Symbol
             (env.unique_symbol(), body)
         }
-        Shadowed(region, loc_ident) => {
+        Shadowed(region, loc_ident, new_symbol) => {
             let error = roc_problem::can::RuntimeError::Shadowing {
                 original_region: *region,
                 shadow: loc_ident.clone(),
             };
-            (env.unique_symbol(), Loc::at_zero(RuntimeError(error)))
+            (*new_symbol, Loc::at_zero(RuntimeError(error)))
         }
 
         UnsupportedPattern(region) => {
@@ -5118,11 +5118,10 @@ fn register_capturing_closure<'a>(
 
         let is_self_recursive = !matches!(recursive, roc_can::expr::Recursive::NotRecursive);
 
-        // does this function capture any local values?
+        let captured_symbols = match *env.subs.get_content_without_compacting(function_type) {
-        let function_layout = layout_cache.raw_from_var(env.arena, function_type, env.subs);
+            Content::Structure(FlatType::Func(_, closure_var, _)) => {
-
+                match LambdaSet::from_var(env.arena, env.subs, closure_var, env.ptr_bytes) {
-        let captured_symbols = match function_layout {
+                    Ok(lambda_set) => {
-            Ok(RawFunctionLayout::Function(_, lambda_set, _)) => {
                         if let Layout::Struct(&[]) = lambda_set.runtime_representation() {
                             CapturedSymbols::None
                         } else {
@@ -5131,18 +5130,6 @@ fn register_capturing_closure<'a>(
                             CapturedSymbols::Captured(temp.into_bump_slice())
                         }
                     }
-            Ok(RawFunctionLayout::ZeroArgumentThunk(_)) => {
-                // top-level thunks cannot capture any variables
-                debug_assert!(
-                    captured_symbols.is_empty(),
-                    "{:?} with layout {:?} {:?} {:?}",
-                    &captured_symbols,
-                    function_layout,
-                    env.subs,
-                    (function_type, closure_type, closure_ext_var),
-                );
-                CapturedSymbols::None
-            }
                     Err(_) => {
                         // just allow this. see https://github.com/rtfeldman/roc/issues/1585
                         if captured_symbols.is_empty() {
@@ -5153,6 +5140,20 @@ fn register_capturing_closure<'a>(
                             CapturedSymbols::Captured(temp.into_bump_slice())
                         }
                     }
+                }
+            }
+            _ => {
+                // This is a value (zero-argument thunk); it cannot capture any variables.
+                debug_assert!(
+                    captured_symbols.is_empty(),
+                    "{:?} with layout {:?} {:?} {:?}",
+                    &captured_symbols,
+                    layout_cache.raw_from_var(env.arena, function_type, env.subs),
+                    env.subs,
+                    (function_type, closure_type, closure_ext_var),
+                );
+                CapturedSymbols::None
+            }
         };
 
         let partial_proc = PartialProc::from_named_function(
@@ -7652,7 +7653,7 @@ fn from_can_pattern_help<'a>(
             }
         }
         StrLiteral(v) => Ok(Pattern::StrLiteral(v.clone())),
-        Shadowed(region, ident) => Err(RuntimeError::Shadowing {
+        Shadowed(region, ident, _new_symbol) => Err(RuntimeError::Shadowing {
             original_region: *region,
             shadow: ident.clone(),
         }),

compiler/mono/src/layout.rs

@@ -7,7 +7,7 @@ use roc_module::ident::{Lowercase, TagName};
 use roc_module::symbol::{Interns, Symbol};
 use roc_problem::can::RuntimeError;
 use roc_types::subs::{
-    Content, FlatType, RecordFields, Subs, UnionTags, Variable, VariableSubsSlice,
+    Content, FlatType, RecordFields, Subs, UnionTags, UnsortedUnionTags, Variable,
 };
 use roc_types::types::{gather_fields_unsorted_iter, RecordField};
 use std::collections::hash_map::Entry;
@@ -1580,18 +1580,26 @@ fn layout_from_flat_type<'a>(
             }
         }
         TagUnion(tags, ext_var) => {
+            let (tags, ext_var) = tags.unsorted_tags_and_ext(subs, ext_var);
+
             debug_assert!(ext_var_is_empty_tag_union(subs, ext_var));
 
-            Ok(layout_from_tag_union(arena, tags, subs, env.ptr_bytes))
+            Ok(layout_from_tag_union(arena, &tags, subs, env.ptr_bytes))
         }
         FunctionOrTagUnion(tag_name, _, ext_var) => {
-            debug_assert!(ext_var_is_empty_tag_union(subs, ext_var));
+            debug_assert!(
+                ext_var_is_empty_tag_union(subs, ext_var),
+                "If ext_var wasn't empty, this wouldn't be a FunctionOrTagUnion!"
+            );
 
-            let tags = UnionTags::from_tag_name_index(tag_name);
+            let union_tags = UnionTags::from_tag_name_index(tag_name);
+            let (tags, _) = union_tags.unsorted_tags_and_ext(subs, ext_var);
 
-            Ok(layout_from_tag_union(arena, tags, subs, env.ptr_bytes))
+            Ok(layout_from_tag_union(arena, &tags, subs, env.ptr_bytes))
         }
         RecursiveTagUnion(rec_var, tags, ext_var) => {
+            let (tags, ext_var) = tags.unsorted_tags_and_ext(subs, ext_var);
+
             debug_assert!(ext_var_is_empty_tag_union(subs, ext_var));
 
             // some observations
@@ -1603,9 +1611,8 @@ fn layout_from_flat_type<'a>(
             // That means none of the optimizations for enums or single tag tag unions apply
 
             let rec_var = subs.get_root_key_without_compacting(rec_var);
-            let mut tag_layouts = Vec::with_capacity_in(tags.len(), arena);
+            let tags_vec = tags.tags;
-
+            let mut tag_layouts = Vec::with_capacity_in(tags_vec.len(), arena);
-            let tags_vec = cheap_sort_tags(arena, tags, subs);
 
             let mut nullable = None;
 
@@ -1619,7 +1626,7 @@ fn layout_from_flat_type<'a>(
             }
 
             env.insert_seen(rec_var);
-            for (index, (_name, variables)) in tags_vec.into_iter().enumerate() {
+            for (index, &(_name, variables)) in tags_vec.iter().enumerate() {
                 if matches!(nullable, Some(i) if i == index as TagIdIntType) {
                     // don't add the nullable case
                     continue;
@@ -1627,8 +1634,7 @@ fn layout_from_flat_type<'a>(
 
                 let mut tag_layout = Vec::with_capacity_in(variables.len() + 1, arena);
 
-                for var_index in variables {
+                for &var in variables {
-                    let var = subs[var_index];
                     // TODO does this cause problems with mutually recursive unions?
                     if rec_var == subs.get_root_key_without_compacting(var) {
                         tag_layout.push(Layout::RecursivePointer);
@@ -1911,13 +1917,14 @@ fn is_recursive_tag_union(layout: &Layout) -> bool {
 
 fn union_sorted_tags_help_new<'a>(
     arena: &'a Bump,
-    mut tags_vec: Vec<(&'_ TagName, VariableSubsSlice)>,
+    tags_list: &[(&'_ TagName, &[Variable])],
     opt_rec_var: Option<Variable>,
     subs: &Subs,
     ptr_bytes: u32,
 ) -> UnionVariant<'a> {
     // sort up front; make sure the ordering stays intact!
-    tags_vec.sort_unstable_by(|(a, _), (b, _)| a.cmp(b));
+    let mut tags_list = Vec::from_iter_in(tags_list.iter(), arena);
+    tags_list.sort_unstable_by(|(a, _), (b, _)| a.cmp(b));
 
     let mut env = Env {
         arena,
@@ -1926,27 +1933,26 @@ fn union_sorted_tags_help_new<'a>(
         ptr_bytes,
     };
 
-    match tags_vec.len() {
+    match tags_list.len() {
         0 => {
             // trying to instantiate a type with no values
             UnionVariant::Never
         }
         1 => {
-            let (tag_name, arguments) = tags_vec.remove(0);
+            let &(tag_name, arguments) = tags_list.remove(0);
             let tag_name = tag_name.clone();
 
             // just one tag in the union (but with arguments) can be a struct
-            let mut layouts = Vec::with_capacity_in(tags_vec.len(), arena);
+            let mut layouts = Vec::with_capacity_in(tags_list.len(), arena);
 
             // special-case NUM_AT_NUM: if its argument is a FlexVar, make it Int
             match tag_name {
                 TagName::Private(Symbol::NUM_AT_NUM) => {
-                    let var = subs[arguments.into_iter().next().unwrap()];
+                    let var = arguments[0];
                     layouts.push(unwrap_num_tag(subs, var, ptr_bytes).expect("invalid num layout"));
                 }
                 _ => {
-                    for var_index in arguments {
+                    for &var in arguments {
-                        let var = subs[var_index];
                         match Layout::from_var(&mut env, var) {
                             Ok(layout) => {
                                 layouts.push(layout);
@@ -1989,7 +1995,7 @@ fn union_sorted_tags_help_new<'a>(
         }
         num_tags => {
             // default path
-            let mut answer = Vec::with_capacity_in(tags_vec.len(), arena);
+            let mut answer = Vec::with_capacity_in(tags_list.len(), arena);
             let mut has_any_arguments = false;
 
             let mut nullable: Option<(TagIdIntType, TagName)> = None;
@@ -1997,7 +2003,7 @@ fn union_sorted_tags_help_new<'a>(
             // only recursive tag unions can be nullable
             let is_recursive = opt_rec_var.is_some();
             if is_recursive && GENERATE_NULLABLE {
-                for (index, (name, variables)) in tags_vec.iter().enumerate() {
+                for (index, (name, variables)) in tags_list.iter().enumerate() {
                     if variables.is_empty() {
                         nullable = Some((index as TagIdIntType, (*name).clone()));
                         break;
@@ -2005,7 +2011,7 @@ fn union_sorted_tags_help_new<'a>(
                 }
             }
 
-            for (index, (tag_name, arguments)) in tags_vec.into_iter().enumerate() {
+            for (index, &(tag_name, arguments)) in tags_list.into_iter().enumerate() {
                 // reserve space for the tag discriminant
                 if matches!(nullable, Some((i, _)) if i  as usize == index) {
                     debug_assert!(arguments.is_empty());
@@ -2014,8 +2020,7 @@ fn union_sorted_tags_help_new<'a>(
 
                 let mut arg_layouts = Vec::with_capacity_in(arguments.len() + 1, arena);
 
-                for var_index in arguments {
+                for &var in arguments {
-                    let var = subs[var_index];
                     match Layout::from_var(&mut env, var) {
                         Ok(layout) => {
                             has_any_arguments = true;
@@ -2326,38 +2331,15 @@ pub fn union_sorted_tags_help<'a>(
     }
 }
 
-fn cheap_sort_tags<'a, 'b>(
-    arena: &'a Bump,
-    tags: UnionTags,
-    subs: &'b Subs,
-) -> Vec<'a, (&'b TagName, VariableSubsSlice)> {
-    let mut tags_vec = Vec::with_capacity_in(tags.len(), arena);
-
-    for (tag_index, index) in tags.iter_all() {
-        let tag = &subs[tag_index];
-        let slice = subs[index];
-
-        tags_vec.push((tag, slice));
-    }
-
-    tags_vec
-}
-
 fn layout_from_newtype<'a>(
     arena: &'a Bump,
-    tags: UnionTags,
+    tags: &UnsortedUnionTags,
     subs: &Subs,
     ptr_bytes: u32,
 ) -> Layout<'a> {
     debug_assert!(tags.is_newtype_wrapper(subs));
 
-    let slice_index = tags.variables().into_iter().next().unwrap();
+    let (tag_name, var) = tags.get_newtype(subs);
-    let slice = subs[slice_index];
-    let var_index = slice.into_iter().next().unwrap();
-    let var = subs[var_index];
-
-    let tag_name_index = tags.tag_names().into_iter().next().unwrap();
-    let tag_name = &subs[tag_name_index];
 
     if tag_name == &TagName::Private(Symbol::NUM_AT_NUM) {
         unwrap_num_tag(subs, var, ptr_bytes).expect("invalid Num argument")
@@ -2388,7 +2370,7 @@ fn layout_from_newtype<'a>(
 
 fn layout_from_tag_union<'a>(
     arena: &'a Bump,
-    tags: UnionTags,
+    tags: &UnsortedUnionTags,
     subs: &Subs,
     ptr_bytes: u32,
 ) -> Layout<'a> {
@@ -2398,14 +2380,13 @@ fn layout_from_tag_union<'a>(
         return layout_from_newtype(arena, tags, subs, ptr_bytes);
     }
 
-    let tags_vec = cheap_sort_tags(arena, tags, subs);
+    let tags_vec = &tags.tags;
 
     match tags_vec.get(0) {
         Some((tag_name, arguments)) if *tag_name == &TagName::Private(Symbol::NUM_AT_NUM) => {
             debug_assert_eq!(arguments.len(), 1);
 
-            let var_index = arguments.into_iter().next().unwrap();
+            let &var = arguments.iter().next().unwrap();
-            let var = subs[var_index];
 
             unwrap_num_tag(subs, var, ptr_bytes).expect("invalid Num argument")
         }

compiler/test_gen/src/gen_tags.rs

@@ -1367,3 +1367,85 @@ fn monomorphized_tag_with_polymorphic_arg_and_monomorphic_arg() {
         u8
     )
 }
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn issue_2365_monomorphize_tag_with_non_empty_ext_var() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+            app "test" provides [main] to "./platform"
+
+            Single a : [A, B, C]a
+            Compound a : Single [D, E, F]a
+
+            single : {} -> Single *
+            single = \{} -> C
+
+            compound : {} -> Compound *
+            compound = \{} -> single {}
+
+            main = compound {}
+            "#
+        ),
+        2, // C
+        u8
+    )
+}
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn issue_2365_monomorphize_tag_with_non_empty_ext_var_wrapped() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+            app "test" provides [main] to "./platform"
+
+            Single a : [A, B, C]a
+            Compound a : Single [D, E, F]a
+
+            single : {} -> Result Str (Single *)
+            single = \{} -> Err C
+
+            compound : {} -> Result Str (Compound *)
+            compound = \{} ->
+                when single {} is
+                    Ok s -> Ok s
+                    Err e -> Err e
+
+            main = compound {}
+            "#
+        ),
+        2, // C
+        u8
+    )
+}
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn issue_2365_monomorphize_tag_with_non_empty_ext_var_wrapped_nested() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+            app "test" provides [main] to "./platform"
+
+            Single a : [A, B, C]a
+            Compound a : Single [D, E, F]a
+
+            main =
+                single : {} -> Result Str (Single *)
+                single = \{} -> Err C
+
+                compound : {} -> Result Str (Compound *)
+                compound = \{} ->
+                    when single {} is
+                        Ok s -> Ok s
+                        Err e -> Err e
+
+                compound {}
+            "#
+        ),
+        2, // C
+        u8
+    )
+}

compiler/types/src/pretty_print.rs

@@ -406,8 +406,8 @@ fn write_sorted_tags2<'a>(
     ext_var: Variable,
 ) -> ExtContent<'a> {
     // Sort the fields so they always end up in the same order.
-    let (it, new_ext_var) = tags.unsorted_iterator_and_ext(subs, ext_var);
+    let (tags, new_ext_var) = tags.unsorted_tags_and_ext(subs, ext_var);
-    let mut sorted_fields: Vec<_> = it.collect();
+    let mut sorted_fields = tags.tags;
 
     let interns = &env.interns;
     let home = env.home;

compiler/types/src/subs.rs

@@ -1813,16 +1813,17 @@ impl UnionTags {
         it.map(f)
     }
 
-    pub fn unsorted_iterator_and_ext<'a>(
+    #[inline(always)]
+    pub fn unsorted_tags_and_ext<'a>(
         &'a self,
         subs: &'a Subs,
         ext: Variable,
-    ) -> (impl Iterator<Item = (&TagName, &[Variable])> + 'a, Variable) {
+    ) -> (UnsortedUnionTags<'a>, Variable) {
         let (it, ext) = crate::types::gather_tags_unsorted_iter(subs, *self, ext);
-
         let f = move |(label, slice): (_, SubsSlice<Variable>)| (label, subs.get_subs_slice(slice));
+        let it = it.map(f);
 
-        (it.map(f), ext)
+        (UnsortedUnionTags { tags: it.collect() }, ext)
     }
 
     #[inline(always)]
@@ -1877,6 +1878,25 @@ impl UnionTags {
     }
 }
 
+#[derive(Debug)]
+pub struct UnsortedUnionTags<'a> {
+    pub tags: Vec<(&'a TagName, &'a [Variable])>,
+}
+
+impl<'a> UnsortedUnionTags<'a> {
+    pub fn is_newtype_wrapper(&self, _subs: &Subs) -> bool {
+        if self.tags.len() != 1 {
+            return false;
+        }
+        self.tags[0].1.len() == 1
+    }
+
+    pub fn get_newtype(&self, _subs: &Subs) -> (&TagName, Variable) {
+        let (tag_name, vars) = self.tags[0];
+        (tag_name, vars[0])
+    }
+}
+
 pub type SortedTagsIterator<'a> = Box<dyn Iterator<Item = (TagName, &'a [Variable])> + 'a>;
 pub type SortedTagsSlicesIterator<'a> = Box<dyn Iterator<Item = (TagName, VariableSubsSlice)> + 'a>;
 
@@ -2025,6 +2045,21 @@ impl RecordFields {
         it
     }
 
+    #[inline(always)]
+    pub fn unsorted_iterator_and_ext<'a>(
+        &'a self,
+        subs: &'a Subs,
+        ext: Variable,
+    ) -> (
+        impl Iterator<Item = (&Lowercase, RecordField<Variable>)> + 'a,
+        Variable,
+    ) {
+        let (it, ext) = crate::types::gather_fields_unsorted_iter(subs, *self, ext)
+            .expect("Something weird ended up in a record type");
+
+        (it, ext)
+    }
+
     /// Get a sorted iterator over the fields of this record type
     ///
     /// Implementation: When the record has an `ext` variable that is the empty record, then

error_macros/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "roc_error_macros"
+version = "0.1.0"
+authors = ["The Roc Contributors"]
+license = "UPL-1.0"
+edition = "2018"
+
+[dependencies]

error_macros/src/lib.rs

@@ -0,0 +1,31 @@
+/// `internal_error!` should be used whenever a compiler invariant is broken.
+/// It is a wrapper around panic that tells the user to file a bug.
+/// This should only be used in cases where there would be a compiler bug and the user can't fix it.
+/// If there is simply an unimplemented feature, please use `unimplemented!`
+/// If there is a user error, please use roc_reporting to print a nice error message.
+#[macro_export]
+macro_rules! internal_error {
+    ($($arg:tt)*) => ({
+        eprintln!("An internal compiler expectation was broken.");
+        eprintln!("This is definitely a compiler bug.");
+        // TODO: update this to the new bug template.
+        eprintln!("Please file an issue here: https://github.com/rtfeldman/roc/issues/new/choose");
+        #[allow(clippy::panic)] {
+            panic!($($arg)*);
+        }
+    })
+}
+
+/// `user_error!` should only ever be used temporarily.
+/// It is a way to document locations where we do not yet have nice error reporting.
+/// All cases of `user_error!` should eventually be replaced with pretty error printing using roc_reporting.
+#[macro_export]
+macro_rules! user_error {
+    ($($arg:tt)*) => ({
+        eprintln!("We ran into an issue while compiling your code.");
+        eprintln!("Sadly, we don't havs a pretty error message for this case yet.");
+        eprintln!("If you can't figure out the problem from the context below, please reach out at: https://roc.zulipchat.com/");
+        eprintln!($($arg)*);
+        std::process::exit(1);
+    })
+}

examples/benchmarks/Deriv.roc

@@ -21,22 +21,6 @@ main =
 
                 |> Task.map (\_ -> {})
 
-nest : (I64, Expr -> IO Expr), I64, Expr -> IO Expr
-nest = \f, n, e -> Task.loop { s: n, f, m: n, x: e } nestHelp
-
-State : { s : I64, f : I64, Expr -> IO Expr, m : I64, x : Expr }
-
-nestHelp : State -> IO [ Step State, Done Expr ]
-nestHelp = \{ s, f, m, x } ->
-    when m is
-        0 ->
-            Task.succeed (Done x)
-
-        _ ->
-            w <- Task.after (f (s - m) x)
-
-            Task.succeed (Step { s, f, m: (m - 1), x: w })
-
 Expr : [ Val I64, Var Str, Add Expr Expr, Mul Expr Expr, Pow Expr Expr, Ln Expr ]
 
 divmod : I64, I64 -> Result { div : I64, mod : I64 } [ DivByZero ]*
@@ -196,6 +180,18 @@ count = \expr ->
         Ln f ->
             count f
 
+nest : (I64, Expr -> IO Expr), I64, Expr -> IO Expr
+nest = \f, n, e -> nestHelp n f n e
+
+nestHelp : I64, (I64, Expr -> IO Expr), I64, Expr -> IO Expr
+nestHelp = \s, f, m, x ->
+    when m is
+        0 ->
+            Task.succeed x
+
+        _ ->
+            f (s - m) x |> Task.after \w -> nestHelp s f (m - 1) w
+
 deriv : I64, Expr -> IO Expr
 deriv = \i, f ->
     fprime = d "x" f

examples/false-interpreter/False.roc

@@ -89,10 +89,6 @@ isWhitespace = \char ->
         == 0x9# tab
 interpretCtx : Context -> Task Context InterpreterErrors
 interpretCtx = \ctx ->
-    Task.loop ctx interpretCtxLoop
-
-interpretCtxLoop : Context -> Task [ Step Context, Done Context ] InterpreterErrors
-interpretCtxLoop = \ctx ->
     when ctx.state is
         Executing if Context.inWhileScope ctx ->
             # Deal with the current while loop potentially looping.
@@ -108,11 +104,11 @@ interpretCtxLoop = \ctx ->
                                     if n == 0 then
                                         newScope = { scope & whileInfo: None }
 
-                                        Task.succeed (Step { popCtx & scopes: List.set ctx.scopes last newScope })
+                                        interpretCtx { popCtx & scopes: List.set ctx.scopes last newScope }
                                     else
                                         newScope = { scope & whileInfo: Some { state: InBody, body, cond } }
 
-                                        Task.succeed (Step { popCtx & scopes: List.append (List.set ctx.scopes last newScope) { data: None, buf: body, index: 0, whileInfo: None } })
+                                        interpretCtx { popCtx & scopes: List.append (List.set ctx.scopes last newScope) { data: None, buf: body, index: 0, whileInfo: None } }
 
                                 Err e ->
                                     Task.fail e
@@ -121,7 +117,7 @@ interpretCtxLoop = \ctx ->
                             # Just rand the body. Run the condition again.
                             newScope = { scope & whileInfo: Some { state: InCond, body, cond } }
 
-                            Task.succeed (Step { ctx & scopes: List.append (List.set ctx.scopes last newScope) { data: None, buf: cond, index: 0, whileInfo: None } })
+                            interpretCtx { ctx & scopes: List.append (List.set ctx.scopes last newScope) { data: None, buf: cond, index: 0, whileInfo: None } }
 
                         None ->
                             Task.fail NoScope
@@ -135,7 +131,7 @@ interpretCtxLoop = \ctx ->
             when result is
                 Ok (T val newCtx) ->
                     execCtx <- Task.await (stepExecCtx newCtx val)
-                    Task.succeed (Step execCtx)
+                    interpretCtx execCtx
 
                 Err NoScope ->
                     Task.fail NoScope
@@ -147,9 +143,9 @@ interpretCtxLoop = \ctx ->
 
                     # If no scopes left, all execution complete.
                     if List.isEmpty dropCtx.scopes then
-                        Task.succeed (Done dropCtx)
+                        Task.succeed dropCtx
                     else
-                        Task.succeed (Step dropCtx)
+                        interpretCtx dropCtx
 
         InComment ->
             result <- Task.attempt (Context.getChar ctx)
@@ -157,9 +153,9 @@ interpretCtxLoop = \ctx ->
                 Ok (T val newCtx) ->
                     if val == 0x7D then
                         # `}` end of comment
-                        Task.succeed (Step { newCtx & state: Executing })
+                        interpretCtx { newCtx & state: Executing }
                     else
-                        Task.succeed (Step { newCtx & state: InComment })
+                        interpretCtx { newCtx & state: InComment }
 
                 Err NoScope ->
                     Task.fail NoScope
@@ -178,13 +174,13 @@ interpretCtxLoop = \ctx ->
                         # so this is make i64 mul by 10 then convert back to i32.
                         nextAccum = (10 * Num.intCast accum) + Num.intCast (val - 0x30)
 
-                        Task.succeed (Step { newCtx & state: InNumber (Num.intCast nextAccum) })
+                        interpretCtx { newCtx & state: InNumber (Num.intCast nextAccum) }
                     else
                         # outside of number now, this needs to be executed.
                         pushCtx = Context.pushStack newCtx (Number accum)
 
                         execCtx <- Task.await (stepExecCtx { pushCtx & state: Executing } val)
-                        Task.succeed (Step execCtx)
+                        interpretCtx execCtx
 
                 Err NoScope ->
                     Task.fail NoScope
@@ -201,12 +197,12 @@ interpretCtxLoop = \ctx ->
                         when Str.fromUtf8 bytes is
                             Ok str ->
                                 {  } <- Task.await (Stdout.raw str)
-                                Task.succeed (Step { newCtx & state: Executing })
+                                interpretCtx { newCtx & state: Executing }
 
                             Err _ ->
                                 Task.fail BadUtf8
                     else
-                        Task.succeed (Step { newCtx & state: InString (List.append bytes val) })
+                        interpretCtx { newCtx & state: InString (List.append bytes val) }
 
                 Err NoScope ->
                     Task.fail NoScope
@@ -220,17 +216,17 @@ interpretCtxLoop = \ctx ->
                 Ok (T val newCtx) ->
                     if val == 0x5B then
                         # start of a nested lambda `[`
-                        Task.succeed (Step { newCtx & state: InLambda (depth + 1) (List.append bytes val) })
+                        interpretCtx { newCtx & state: InLambda (depth + 1) (List.append bytes val) }
                     else if val == 0x5D then
                         # `]` end of current lambda
                         if depth == 0 then
                             # end of all lambdas
-                            Task.succeed (Step (Context.pushStack { newCtx & state: Executing } (Lambda bytes)))
+                            interpretCtx (Context.pushStack { newCtx & state: Executing } (Lambda bytes))
                         else
                             # end of nested lambda
-                            Task.succeed (Step { newCtx & state: InLambda (depth - 1) (List.append bytes val) })
+                            interpretCtx { newCtx & state: InLambda (depth - 1) (List.append bytes val) }
                     else
-                        Task.succeed (Step { newCtx & state: InLambda depth (List.append bytes val) })
+                        interpretCtx { newCtx & state: InLambda depth (List.append bytes val) }
 
                 Err NoScope ->
                     Task.fail NoScope
@@ -256,14 +252,14 @@ interpretCtxLoop = \ctx ->
 
                     when result2 is
                         Ok a ->
-                            Task.succeed (Step a)
+                            interpretCtx a
 
                         Err e ->
                             Task.fail e
 
                 Ok (T 0x9F newCtx) ->
                     # This is supposed to flush io buffers. We don't buffer, so it does nothing
-                    Task.succeed (Step newCtx)
+                    interpretCtx newCtx
 
                 Ok (T x _) ->
                     data = Num.toStr (Num.intCast x)
@@ -280,7 +276,7 @@ interpretCtxLoop = \ctx ->
             result <- Task.attempt (Context.getChar { ctx & state: Executing })
             when result is
                 Ok (T x newCtx) ->
-                    Task.succeed (Step (Context.pushStack newCtx (Number (Num.intCast x))))
+                    interpretCtx (Context.pushStack newCtx (Number (Num.intCast x)))
 
                 Err NoScope ->
                     Task.fail NoScope

examples/false-interpreter/platform/Task.roc

@@ -1,27 +1,9 @@
 interface Task
-    exposes [ Task, succeed, fail, await, map, onFail, attempt, fromResult, loop ]
+    exposes [ Task, succeed, fail, await, map, onFail, attempt, fromResult ]
     imports [ fx.Effect ]
 
 Task ok err : Effect.Effect (Result ok err)
 
-loop : state, (state -> Task [ Step state, Done done ] err) -> Task done err
-loop = \state, step ->
-    looper = \current ->
-        step current
-            |> Effect.map
-            \res ->
-                when res is
-                    Ok (Step newState) ->
-                        Step newState
-
-                    Ok (Done result) ->
-                        Done (Ok result)
-
-                    Err e ->
-                        Done (Err e)
-
-    Effect.loop state looper
-
 succeed : val -> Task val *
 succeed = \val ->
     Effect.always (Ok val)

reporting/src/lib.rs

@@ -4,35 +4,3 @@
 
 pub mod error;
 pub mod report;
-
-/// `internal_error!` should be used whenever a compiler invariant is broken.
-/// It is a wrapper around panic that tells the user to file a bug.
-/// This should only be used in cases where there would be a compiler bug and the user can't fix it.
-/// If there is simply an unimplemented feature, please use `unimplemented!`
-/// If there is a user error, please use roc_reporting to print a nice error message.
-#[macro_export]
-macro_rules! internal_error {
-    ($($arg:tt)*) => ({
-        eprintln!("An internal compiler expectation was broken.");
-        eprintln!("This is definitely a compiler bug.");
-        // TODO: update this to the new bug template.
-        eprintln!("Please file an issue here: https://github.com/rtfeldman/roc/issues/new/choose");
-        #[allow(clippy::panic)] {
-            panic!($($arg)*);
-        }
-    })
-}
-
-/// `user_error!` should only ever be used temporarily.
-/// It is a way to document locations where we do not yet have nice error reporting.
-/// All cases of `user_error!` should eventually be replaced with pretty error printing using roc_reporting.
-#[macro_export]
-macro_rules! user_error {
-    ($($arg:tt)*) => ({
-        eprintln!("We ran into an issue while compiling your code.");
-        eprintln!("Sadly, we don't havs a pretty error message for this case yet.");
-        eprintln!("If you can't figure out the problem from the context below, please reach out at: https://roc.zulipchat.com/");
-        eprintln!($($arg)*);
-        std::process::exit(1);
-    })
-}

reporting/tests/test_reporting.rs

@@ -424,6 +424,16 @@ mod test_reporting {
 
                 `Booly` is not used anywhere in your code.
 
+                3│  Booly : [ Yes, No, Maybe ]
+                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
+                
+                If you didn't intend on using `Booly` then remove it so future readers
+                of your code don't wonder why it is there.
+                
+                ── UNUSED DEFINITION ───────────────────────────────────────────────────────────
+                
+                `Booly` is not used anywhere in your code.
+                
                 1│  Booly : [ Yes, No ]
                     ^^^^^^^^^^^^^^^^^^^