I got a crash when I was compiling a test. Clang12 using c++20 templated lambdas

[Sebanisu]

Bugzilla Link	49719
Version	trunk
OS	Linux
Attachments	reduced test case
CC	@zygoloid

Extended Description

Stack dump:
0. Program arguments: /usr/lib/llvm-12/bin/clang -cc1 -triple x86_64-pc-linux-gnu -emit-obj -mrelax-all --mrelax-relocations -disable-free -disable-llvm-verifier -discard-value-names -main-file-name random_test.cpp -mrelocation-model static -mframe-pointer=all -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -fno-split-dwarf-inlining -debug-info-kind=limited -dwarf-version=4 -debugger-tuning=gdb -sys-header-deps -D CMAKE_INTDIR="Debug" -Wall -Wextra -Wshadow -Wno-error=shadow -Wnon-virtual-dtor -Wold-style-cast -Wcast-align -Wunused -Woverloaded-virtual -Wpedantic -Wconversion -Wsign-conversion -Wnull-dereference -Wdouble-promotion -Wformat=2 -Werror -std=c++20 -fdeprecated-macro -ferror-limit 19 -fgnuc-version=4.2.1 -fno-implicit-modules -fcxx-exceptions -fexceptions -faddrsig -x c++ random_test-7f79f0.cpp

1.  random_test-7f79f0.cpp:2:21: current parser token ')'
   

2.  random_test-7f79f0.cpp:1:23: instantiating function definition '(anonymous class)::operator()<>'
   

#​0 0x00007f7ffc838ea3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/lib/x86_64-linux-gnu/libLLVM-12.so.1+0xbd8ea3)
#​1 0x00007f7ffc8371c0 llvm::sys::RunSignalHandlers() (/lib/x86_64-linux-gnu/libLLVM-12.so.1+0xbd71c0)
#​2 0x00007f7ffc83950f (/lib/x86_64-linux-gnu/libLLVM-12.so.1+0xbd950f)
#​3 0x00007f80040823c0 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x153c0)
#​4 0x00007f8001e3004e clang::ASTContext::getSubstTemplateTypeParmType(clang::TemplateTypeParmType const*, clang::QualType) const (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0xa1004e)
#​5 0x00007f80028e3028 (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14c3028)
#​6 0x00007f80028df7a2 (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14bf7a2)
#​7 0x00007f80028e4b03 clang::Sema::SubstParmVarDecl(clang::ParmVarDecl*, clang::MultiLevelTemplateArgumentList const&, int, llvm::Optional, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14c4b03)
#​8 0x00007f8002927474 (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x1507474)
#​9 0x00007f8002379f3b clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0xf59f3b)
#​10 0x00007f800292056b clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x150056b)
#​11 0x00007f8002912bc8 clang::Sema::FindInstantiatedDecl(clang::SourceLocation, clang::NamedDecl*, clang::MultiLevelTemplateArgumentList const&, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14f2bc8)
#​12 0x00007f80028fbab4 (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14dbab4)
#​13 0x00007f80028ea282 (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14ca282)
#​14 0x00007f80029003fe (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14e03fe)
#​15 0x00007f80028ea221 clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x14ca221)
#​16 0x00007f8002922b1e clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x1502b1e)
#​17 0x00007f8002379f3b clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0xf59f3b)
#​18 0x00007f800289c6f0 clang::Sema::DeduceReturnType(clang::FunctionDecl*, clang::SourceLocation, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x147c6f0)
#​19 0x00007f80025a981b clang::Sema::DiagnoseUseOfDecl(clang::NamedDecl*, llvm::ArrayRefclang::SourceLocation, clang::ObjCInterfaceDecl const*, bool, bool, clang::ObjCInterfaceDecl*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x118981b)
#​20 0x00007f80027d7250 (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x13b7250)
#​21 0x00007f80027dd875 clang::Sema::BuildCallToObjectOfClassType(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRefclang::Expr*, clang::SourceLocation) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x13bd875)
#​22 0x00007f80025c3aea clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRefclang::Expr*, clang::SourceLocation, clang::Expr*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x11a3aea)
#​23 0x00007f8001d984c1 clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9784c1)
#​24 0x00007f8001d995c4 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9795c4)
#​25 0x00007f8001d97371 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x977371)
#​26 0x00007f8001d95c73 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x975c73)
#​27 0x00007f8001d7d8fd clang::Parser::ParseParameterDeclarationClause(clang::DeclaratorContext, clang::ParsedAttributes&, llvm::SmallVectorImplclang::DeclaratorChunk::ParamInfo&, clang::SourceLocation&) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x95d8fd)
#​28 0x00007f8001d7b135 clang::Parser::ParseFunctionDeclarator(clang::Declarator&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&, bool, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x95b135)
#​29 0x00007f8001d79396 clang::Parser::ParseDirectDeclarator(clang::Declarator&) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x959396)
#​30 0x00007f8001d772b3 clang::Parser::ParseDeclaratorInternal(clang::Declarator&, void (clang::Parser::)(clang::Declarator&)) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9572b3)
#​31 0x00007f8001d6d61b clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::SourceLocation, clang::Parser::ForRangeInit*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x94d61b)
#​32 0x00007f8001e0a91d clang::Parser::ParseDeclOrFunctionDefInternal(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9ea91d)
#​33 0x00007f8001e0a32c clang::Parser::ParseDeclarationOrFunctionDefinition(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9ea32c)
#​34 0x00007f8001e094cf clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9e94cf)
#​35 0x00007f8001e07cbf clang::Parser::ParseTopLevelDecl(clang::OpaquePtrclang::DeclGroupRef&, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9e7cbf)
#​36 0x00007f8001e076d7 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtrclang::DeclGroupRef&) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x9e76d7)
#​37 0x00007f8001d58ce7 clang::ParseAST(clang::Sema&, bool, bool) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x938ce7)
#​38 0x00007f80032ee068 clang::FrontendAction::Execute() (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x1ece068)
#​39 0x00007f800327bd21 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x1e5bd21)
#​40 0x00007f8003350452 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/lib/x86_64-linux-gnu/libclang-cpp.so.12+0x1f30452)
#​41 0x0000000000412782 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm-12/bin/clang+0x412782)
#​42 0x0000000000410afe (/usr/lib/llvm-12/bin/clang+0x410afe)
#​43 0x000000000041090e main (/usr/lib/llvm-12/bin/clang+0x41090e)
#​44 0x00007f7ffb7170b3 __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:342:3
#​45 0x000000000040dcbe _start (/usr/lib/llvm-12/bin/clang+0x40dcbe)

Crash reproducer for Ubuntu clang version 12.0.0-++20210316012635+00441b8f4e5b-1exp120210316123347.61

Driver args: "--driver-mode=g++" "-D" "CMAKE_INTDIR="Debug"" "-I" "../tests/src" "-I" "_deps/ut-src/include" "-I" "../src" "-g" "-Wall" "-Wextra" "-Wshadow" "-Wno-error=shadow" "-Wnon-virtual-dtor" "-Wold-style-cast" "-Wcast-align" "-Wunused" "-Woverloaded-virtual" "-Wpedantic" "-Wconversion" "-Wsign-conversion" "-Wnull-dereference" "-Wdouble-promotion" "-Wformat=2" "-Werror" "-stdlib=libc++" "-std=c++20" "-MD" "-MT" "tests/src/CMakeFiles/ToolsLibrary_random_test.dir/Debug/random_test.cpp.o" "-MF" "tests/src/CMakeFiles/ToolsLibrary_random_test.dir/Debug/random_test.cpp.o.d" "-o" "tests/src/CMakeFiles/ToolsLibrary_random_test.dir/Debug/random_test.cpp.o" "-c" "../tests/src/random_test.cpp"

Original command: "/usr/lib/llvm-12/bin/clang" "-cc1" "-triple" "x86_64-pc-linux-gnu" "-emit-obj" "-mrelax-all" "--mrelax-relocations" "-disable-free" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "random_test.cpp" "-mrelocation-model" "static" "-mframe-pointer=all" "-fmath-errno" "-fno-rounding-math" "-mconstructor-aliases" "-munwind-tables" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-fno-split-dwarf-inlining" "-debug-info-kind=limited" "-dwarf-version=4" "-debugger-tuning=gdb" "-resource-dir" "/usr/lib/llvm-12/lib/clang/12.0.0" "-dependency-file" "tests/src/CMakeFiles/ToolsLibrary_random_test.dir/Debug/random_test.cpp.o.d" "-MT" "tests/src/CMakeFiles/ToolsLibrary_random_test.dir/Debug/random_test.cpp.o" "-sys-header-deps" "-D" "CMAKE_INTDIR="Debug"" "-I" "../tests/src" "-I" "_deps/ut-src/include" "-I" "../src" "-internal-isystem" "/usr/lib/llvm-12/bin/../include/c++/v1" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/usr/lib/llvm-12/lib/clang/12.0.0/include" "-internal-externc-isystem" "/usr/include/x86_64-linux-gnu" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-Wall" "-Wextra" "-Wshadow" "-Wno-error=shadow" "-Wnon-virtual-dtor" "-Wold-style-cast" "-Wcast-align" "-Wunused" "-Woverloaded-virtual" "-Wpedantic" "-Wconversion" "-Wsign-conversion" "-Wnull-dereference" "-Wdouble-promotion" "-Wformat=2" "-Werror" "-std=c++20" "-fdeprecated-macro" "-fdebug-compilation-dir" "/mnt/d/dev/ToolsLibrary/build" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fno-implicit-modules" "-fcxx-exceptions" "-fexceptions" "-faddrsig" "-o" "tests/src/CMakeFiles/ToolsLibrary_random_test.dir/Debug/random_test.cpp.o" "-x" "c++" "../tests/src/random_test.cpp"

"/usr/lib/llvm-12/bin/clang" "-cc1" "-triple" "x86_64-pc-linux-gnu" "-emit-obj" "-mrelax-all" "--mrelax-relocations" "-disable-free" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "random_test.cpp" "-mrelocation-model" "static" "-mframe-pointer=all" "-fmath-errno" "-fno-rounding-math" "-mconstructor-aliases" "-munwind-tables" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-fno-split-dwarf-inlining" "-debug-info-kind=limited" "-dwarf-version=4" "-debugger-tuning=gdb" "-sys-header-deps" "-D" "CMAKE_INTDIR="Debug"" "-Wall" "-Wextra" "-Wshadow" "-Wno-error=shadow" "-Wnon-virtual-dtor" "-Wold-style-cast" "-Wcast-align" "-Wunused" "-Woverloaded-virtual" "-Wpedantic" "-Wconversion" "-Wsign-conversion" "-Wnull-dereference" "-Wdouble-promotion" "-Wformat=2" "-Werror" "-std=c++20" "-fdeprecated-macro" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fno-implicit-modules" "-fcxx-exceptions" "-fexceptions" "-faddrsig" "-x" "c++" "random_test-7f79f0.cpp"

[Sebanisu]

Issue opened about this crash related to this:
Sebanisu/ToolsLibrary#7
Code:
https://github.com/Sebanisu/ToolsLibrary/blob/main/tests/src/random_test.cpp
https://github.com/Sebanisu/ToolsLibrary/blob/main/src/tl/random.hpp
I am unsure if you want this stuff. Let me know if you need more info.

[zygoloid]

Thanks for the reduced testcase! Slightly unreduced back to nearly-valid code:

void f(auto long_name = []<int = 0>() { long_name2; } ());

The explicit template parameter list seems to be necessary here; a generic lambda using (auto) doesn't trigger this.