[C++20] [Modules] Crash with inconsistent deduced type in two importing modules

[gen740]

I created a C++20 modules project incorporating STL libraries, ranges and OpenMP, but it suddenly crashes. I've set up a minimum reproduction project at gen740/InternalCompilerError. (I couldn't minimize the issue further!)

The error message can be found here:
https://github.com/gen740/InternalCompilerError/actions/runs/7592379101/job/20681666596#step:7:33

I also confirmed that this issue occurs in the HEAD branch. However, I can't reproduce it on Compiler Explorer at https://godbolt.org/z/h8M1sq5zc.

[gen740]

I could minimize the setup without OpenMP and standard libraries.

Step to reproduce

• Create following 4 c++ modules files.

// Type.ccm
export module MyVec:Type;

template <class T> struct Size {
  auto total() const { return 1; }
};


// Vec.ccm
export module MyVec:Vec;

import :Type;

int size_ = Size<int>().total();

// Vec2.ccm
export module MyVec:Vec2;

import :Type;

struct Vec2 {
  Size<int> size_;
};

// Calculator.ccm
export module MyVec:Calculator;

import :Vec;
import :Vec2;

auto Calculate() { return Size<int>().total(); };

• Compile with following commands.

$CXX -std=c++23 -c Type.ccm               \
  -fmodule-output=MyVec-Type.pcm
$CXX -std=c++23 -c Vec2.ccm               \
  -fmodule-output=MyVec-Vec2.pcm          \
  -fmodule-file=MyVec:Type=MyVec-Type.pcm
$CXX -std=c++23 -c Vec.ccm                \
  -fmodule-output=MyVec-Vec.pcm           \
  -fmodule-file=MyVec:Type=MyVec-Type.pcm
$CXX -std=c++23 -c Calculator.ccm         \
  -fmodule-output=MyVec-Calculator.pcm    \
  -fmodule-file=MyVec:Vec=MyVec-Vec.pcm   \
  -fmodule-file=MyVec:Vec2=MyVec-Vec2.pcm \
  -fmodule-file=MyVec:Type=MyVec-Type.pcm

Environment

• OS macOS 14.2.1
• clang compiler

Homebrew clang version 17.0.6
Target: x86_64-apple-darwin23.2.0
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin

Output

GitHub Actions

PLEASE submit a bug report to https://github.com/Homebrew/homebrew-core/issues and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: /usr/local/Cellar/llvm/17.0.6_1/bin/clang-17 -cc1 -triple x86_64-apple-macosx14.0.0 -Wundef-prefix=TARGET_OS_ -Werror=undef-prefix -Wdeprecated-objc-isa-usage -Werror=deprecated-objc-isa-usage -emit-obj -mrelax-all -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name Calculator.ccm -mrelocation-model pic -pic-level 2 -mframe-pointer=all -ffp-contract=on -fno-rounding-math -funwind-tables=2 -fcompatibility-qualified-id-block-type-checking -fvisibility-inlines-hidden-static-local-var -target-cpu penryn -tune-cpu generic -debugger-tuning=lldb -target-linker-version 1022.1 -fcoverage-compilation-dir=/Users/gen/home/Labo/InternalCompilerError -resource-dir /usr/local/Cellar/llvm/17.0.6_1/lib/clang/17 -std=c++23 -fdebug-compilation-dir=/Users/gen/home/Labo/InternalCompilerError -ferror-limit 19 -stack-protector 1 -fblocks -fencode-extended-block-signature -fregister-global-dtors-with-atexit -fgnuc-version=4.2.1 -fmodule-file=MyVec:Vec=MyVec-Vec.pcm -fmodule-file=MyVec:Vec2=MyVec-Vec2.pcm -fmodule-file=MyVec:Type=MyVec-Type.pcm -fmax-type-align=16 -fcolor-diagnostics -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o Calculator.o -x pcm MyVec-Calculator.pcm
1.      <eof> parser at end of file
2.      /Users/gen/home/Labo/InternalCompilerError/Calculator.ccm:6:6: LLVM IR generation of declaration 'Calculate'
3.      /Users/gen/home/Labo/InternalCompilerError/Calculator.ccm:6:6: Generating code for declaration 'Calculate'
 #0 0x0000000122b35948 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/local/Cellar/llvm/17.0.6_1/lib/libLLVM.dylib+0x1c7e948)
 #1 0x00000001257146ea SignalHandler(int) (/usr/local/Cellar/llvm/17.0.6_1/lib/libLLVM.dylib+0x485d6ea)
 #2 0x00007ff80f64737d (/usr/lib/system/libsystem_platform.dylib+0x7ff80046937d)
 #3 0x0000000100000004 (/usr/local/Cellar/llvm/17.0.6_1/bin/clang-17+0xf1d8b004)
 #4 0x00000001134f0ad8 (anonymous namespace)::X86_64ABIInfo::computeInfo(clang::CodeGen::CGFunctionInfo&) const (.llvm.1432843204888195738) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x25aad8)
 #5 0x000000011371f5c8 clang::CodeGen::CodeGenTypes::arrangeCXXMethodDeclaration(clang::CXXMethodDecl const*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x4895c8)
 #6 0x00000001142560f4 clang::CodeGen::CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(clang::CallExpr const*, clang::CXXMethodDecl const*, clang::CodeGen::ReturnValueSlot, bool, clang::NestedNameSpecifier*, bool, clang::Expr const*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0xfc00f4)
 #7 0x00000001137390c2 clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x4a30c2)
 #8 0x0000000114c0a15a (anonymous namespace)::ScalarExprEmitter::Visit(clang::Expr*) (.llvm.13750155672644761025) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x197415a)
 #9 0x0000000114c77565 clang::CodeGen::CodeGenFunction::EmitReturnStmt(clang::ReturnStmt const&) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x19e1565)
#10 0x0000000114c74927 clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x19de927)
#11 0x0000000114cb5fda clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x1a1ffda)
#12 0x0000000113acafff clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x834fff)
#13 0x0000000113ad3b26 clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x83db26)
#14 0x000000011378450d clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x4ee50d)
#15 0x000000011432231f clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x108c31f)
#16 0x000000011431af88 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x1084f88)
#17 0x0000000113ae663d (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x85063d)
#18 0x00000001142fdf20 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x1067f20)
#19 0x0000000113bdc140 clang::ASTReader::PassInterestingDeclsToConsumer() (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x946140)
#20 0x00000001160583ff non-virtual thunk to clang::ASTReader::StartTranslationUnit(clang::ASTConsumer*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x2dc23ff)
#21 0x00000001148dba6a clang::ParseAST(clang::Sema&, bool, bool) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x1645a6a)
#22 0x00000001145d506d clang::FrontendAction::Execute() (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x133f06d)
#23 0x0000000113c12b42 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x97cb42)
#24 0x000000011460dab8 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/local/Cellar/llvm/17.0.6_1/lib/libclang-cpp.dylib+0x1377ab8)
#25 0x000000010e279b9b cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/local/Cellar/llvm/17.0.6_1/bin/clang-17+0x100004b9b)
#26 0x000000010e27eed3 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) (/usr/local/Cellar/llvm/17.0.6_1/bin/clang-17+0x100009ed3)
#27 0x000000010e27d893 clang_main(int, char**, llvm::ToolContext const&) (/usr/local/Cellar/llvm/17.0.6_1/bin/clang-17+0x100008893)
#28 0x000000010e289843 main (/usr/local/Cellar/llvm/17.0.6_1/bin/clang-17+0x100014843)
#29 0x00007ff80f28e386
clang++: error: unable to execute command: Segmentation fault: 11
clang++: error: clang frontend command failed due to signal (use -v to see invocation)
Homebrew clang version 17.0.6
Target: x86_64-apple-darwin23.2.0
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin
clang++: note: diagnostic msg:
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang++: note: diagnostic msg: /var/folders/3d/3cl9czgd5c1b8nvtqw_tf4mh0000gp/T/Calculator-b08f2f.cppm
clang++: note: diagnostic msg: /var/folders/3d/3cl9czgd5c1b8nvtqw_tf4mh0000gp/T/Calculator-b08f2f.sh
clang++: note: diagnostic msg: Crash backtrace is located in
clang++: note: diagnostic msg: /Users/gen/Library/Logs/DiagnosticReports/clang-17_<YYYY-MM-DD-HHMMSS>_<hostname>.crash
clang++: note: diagnostic msg: (choose the .crash file that corresponds to your crash)
clang++: note: diagnostic msg:

********************

P.S.
I was able to reproduce this issue on Compiler Explorer (https://godbolt.org/z/7rYaE4jvz).

[llvmbot]

@llvm/issue-subscribers-clang-modules

Author: Gen (gen740)

I created a C++20 modules project incorporating STL libraries, ranges and OpenMP, but it suddenly crashes. I've set up a minimum reproduction project at [gen740/InternalCompilerError](https://github.com/gen740/InternalCompilerError). (I couldn't minimize the issue further!)

The error message can be found here:
https://github.com/gen740/InternalCompilerError/actions/runs/7592379101/job/20681666596#step:7:33

I also confirmed that this issue occurs in the HEAD branch. However, I can't reproduce it on Compiler Explorer at https://godbolt.org/z/h8M1sq5zc.