Files
carbon-lang/toolchain/lower/testdata/function/generic/local_function.carbon
T
Chandler Carruth 8be274cf60 Replace :! binding syntax with phase keywords and contextual defaults (#7479)
Implement the toolchain side of proposal #7254, removing the `:!`
binding
syntax for generic and template parameters in favor of the keywords
`generic`,
`template`, and `runtime` plus contextual defaults for phase.

For valid programs this is semantics-preserving: each binding resolves
to the
same phase, and produces the same SemIR, as it did under `:!`/`:`. The
parser
derives a binding's phase from its syntactic context plus any explicit
phase
keyword; new diagnostics and error recovery for misused keywords are
described
below.

Implementation details for each component:

- Lexer: remove the `:!` (`ColonExclaim`) token, move its virtual
parse-node
  budget onto `:`, and add the `generic` and `runtime` keywords.
- Parser: thread a `BindingContext` (`ExplicitParam`, `DeducedParam`, or
`CompileTimeEntityParam`) from declaration introducers down through
parameter
lists to each binding pattern, using a one-token lookahead to
distinguish a
name-qualifier parameter list from a declaration's own final list.
Parameters
of a compile-time entity (`class`, `interface`, `constraint`, `choice`,
`alias`, `export`, `namespace`) and deduced `[]` parameters default to
checked
generic; explicit function parameters and local bindings default to
runtime.
`HandleBindingPattern` resolves the phase from that context plus the
keyword: a
`generic` keyword needs no node of its own (the phase is carried by the
  binding's node kind), while a `runtime` keyword is preserved as a
`RuntimeBindingName` node so `check` can name it in a diagnostic. A
phase
keyword that is merely redundant with the contextual default is
diagnosed
  here, without invalidating the parse tree.
- Check: a phase keyword that is invalid for its context (for example
`runtime`
on a checked-generic parameter) is diagnosed here, and recovers by
building an
error binding that still introduces the name so that later uses of it do
not
  produce cascading errors.

The removed `:!` syntax is now rejected as an ordinary parse error.

The `form`/`:?`/`->?` ("extended types") portion of proposal #7254 is
left for a
separate change.

Assisted-by: Claude Code
2026-07-11 01:22:44 +00:00

77 lines
3.8 KiB
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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/primitives.carbon
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/lower/testdata/function/generic/local_function.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/lower/testdata/function/generic/local_function.carbon
// Test that calling a local function defined inside a generic function works.
// This previously crashed due to the local function not having a parent name
// scope.
fn F(generic T: Core.Copy, y: T) -> T {
fn G(x: T) -> T { return x; }
return G(y);
}
fn Run() -> i32 {
return F(i32, 0);
}
// CHECK:STDOUT: ; ---
// CHECK:STDOUT: ; ModuleID = 'local_function.carbon'
// CHECK:STDOUT: source_filename = "local_function.carbon"
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nounwind
// CHECK:STDOUT: define i32 @main() #0 !dbg !4 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %F.call = call i32 @_CF.Main.5bd8d5767580997a(i32 0), !dbg !8
// CHECK:STDOUT: ret i32 %F.call, !dbg !9
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nounwind
// CHECK:STDOUT: define linkonce_odr i32 @_CF.Main.5bd8d5767580997a(i32 %y) #0 !dbg !10 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %G.call = call i32 @"_CG:enclosed.5bd8d5767580997a"(i32 %y), !dbg !15
// CHECK:STDOUT: ret i32 %G.call, !dbg !16
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nounwind
// CHECK:STDOUT: define linkonce_odr i32 @"_CG:enclosed.5bd8d5767580997a"(i32 %x) #0 !dbg !17 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: ret i32 %x, !dbg !20
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: attributes #0 = { nounwind }
// CHECK:STDOUT:
// CHECK:STDOUT: !llvm.dbg.cu = !{!0}
// CHECK:STDOUT: !llvm.module.flags = !{!2, !3}
// CHECK:STDOUT:
// CHECK:STDOUT: !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
// CHECK:STDOUT: !1 = !DIFile(filename: "local_function.carbon", directory: "")
// CHECK:STDOUT: !2 = !{i32 7, !"Dwarf Version", i32 5}
// CHECK:STDOUT: !3 = !{i32 2, !"Debug Info Version", i32 3}
// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "Run", linkageName: "main", scope: null, file: !1, line: 22, type: !5, spFlags: DISPFlagDefinition, unit: !0)
// CHECK:STDOUT: !5 = !DISubroutineType(types: !6)
// CHECK:STDOUT: !6 = !{!7}
// CHECK:STDOUT: !7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
// CHECK:STDOUT: !8 = !DILocation(line: 23, column: 10, scope: !4)
// CHECK:STDOUT: !9 = !DILocation(line: 23, column: 3, scope: !4)
// CHECK:STDOUT: !10 = distinct !DISubprogram(name: "F", linkageName: "_CF.Main.5bd8d5767580997a", scope: null, file: !1, line: 17, type: !11, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !13)
// CHECK:STDOUT: !11 = !DISubroutineType(types: !12)
// CHECK:STDOUT: !12 = !{!7, !7}
// CHECK:STDOUT: !13 = !{!14}
// CHECK:STDOUT: !14 = !DILocalVariable(arg: 1, scope: !10, type: !7)
// CHECK:STDOUT: !15 = !DILocation(line: 19, column: 10, scope: !10)
// CHECK:STDOUT: !16 = !DILocation(line: 19, column: 3, scope: !10)
// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "G", linkageName: "_CG:enclosed.5bd8d5767580997a", scope: null, file: !1, line: 18, type: !11, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !18)
// CHECK:STDOUT: !18 = !{!19}
// CHECK:STDOUT: !19 = !DILocalVariable(arg: 1, scope: !17, type: !7)
// CHECK:STDOUT: !20 = !DILocation(line: 18, column: 21, scope: !17)
// CHECK:STDOUT: