From 41f47c0e87081573c16ccc5940628ff5f36cd38b Mon Sep 17 00:00:00 2001 From: Roopesh S <119874392+TechWizard9999@users.noreply.github.com> Date: Sat, 21 Feb 2026 03:46:18 +0530 Subject: [PATCH] Fix crash on generic call to local function (#6671) (#6679) ## Summary - Avoid crash in `MangleInverseQualifiedNameScope` by skipping missing name scopes (local functions have no parent scope). - Add regression test: toolchain/lower/testdata/function/generic/local_function.carbon. --------- Co-authored-by: Richard Smith --- toolchain/lower/mangler.cpp | 6 ++ .../function/generic/local_function.carbon | 74 +++++++++++++++++++ 2 files changed, 80 insertions(+) create mode 100644 toolchain/lower/testdata/function/generic/local_function.carbon diff --git a/toolchain/lower/mangler.cpp b/toolchain/lower/mangler.cpp index 8cf42f379e59..6f069c0c2955 100644 --- a/toolchain/lower/mangler.cpp +++ b/toolchain/lower/mangler.cpp @@ -47,6 +47,12 @@ auto Mangler::MangleInverseQualifiedNameScope(llvm::raw_ostream& os, if (prefix) { os << prefix; } + if (!name_scope_id.has_value()) { + // TODO: Include something in the mangling to identify the scope for a + // function-local class, function, or similar. We may need to number + // these within the enclosing function, as their name need not be unique. + continue; + } if (name_scope_id == SemIR::NameScopeId::Package) { auto package_id = sem_ir().package_id(); if (auto ident_id = package_id.AsIdentifierId(); ident_id.has_value()) { diff --git a/toolchain/lower/testdata/function/generic/local_function.carbon b/toolchain/lower/testdata/function/generic/local_function.carbon new file mode 100644 index 000000000000..c5f005ca51a9 --- /dev/null +++ b/toolchain/lower/testdata/function/generic/local_function.carbon @@ -0,0 +1,74 @@ +// 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(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: ; 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.64ccbb8e5d9a0b8e(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.64ccbb8e5d9a0b8e(i32 %y) #0 !dbg !10 { +// CHECK:STDOUT: entry: +// CHECK:STDOUT: %G.call = call i32 @_CG..64ccbb8e5d9a0b8e(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..64ccbb8e5d9a0b8e(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.module.flags = !{!0, !1} +// CHECK:STDOUT: !llvm.dbg.cu = !{!2} +// CHECK:STDOUT: +// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5} +// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3} +// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug) +// CHECK:STDOUT: !3 = !DIFile(filename: "local_function.carbon", directory: "") +// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "Run", linkageName: "main", scope: null, file: !3, line: 22, type: !5, spFlags: DISPFlagDefinition, unit: !2) +// 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.64ccbb8e5d9a0b8e", scope: null, file: !3, line: 17, type: !11, spFlags: DISPFlagDefinition, unit: !2, 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..64ccbb8e5d9a0b8e", scope: null, file: !3, line: 18, type: !11, spFlags: DISPFlagDefinition, unit: !2, 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)