<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Assertion failure with unexpanded variadic pack in concept definition"
href="https://bugs.llvm.org/show_bug.cgi?id=44672">44672</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Assertion failure with unexpanded variadic pack in concept definition
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>C++2a
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>david@doublewise.net
</td>
</tr>
<tr>
<th>CC</th>
<td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
</td>
</tr></table>
<p>
<div>
<pre>The following ill-formed code:
```
template<typename>
int c = 1;
template<typename... Ts>
concept c_wrapper = c<Ts>;
static_assert(c_wrapper<int>);
```
causes clang to crash with
```
clang++: /home/david/llvm/clang/lib/AST/ExprConstant.cpp:13755: bool
clang::Expr::EvaluateAsRValue(clang::Expr::EvalResult &, const
clang::ASTContext &, bool) const: Assertion `!isValueDependent() && "Expression
evaluator can't be called on a dependent expression."' failed.
Stack dump:
0. Program arguments: /home/david/llvm/build/bin/clang++ -g -o
/tmp/compiler-explorer-compiler120026-63259-279ley.8vya3/output.s -mllvm
--x86-asm-syntax=intel -S -std=c++2a -fcolor-diagnostics -fno-crash-diagnostics
<source>
1. <source>:7:29: current parser token ')'
#0 0x000055b246c107e2 PrintStackTraceSignalHandler(void*)
(/home/david/llvm/build/bin/clang+++0x31f27e2)
#1 0x000055b246c0e14e llvm::sys::RunSignalHandlers()
(/home/david/llvm/build/bin/clang+++0x31f014e)
#2 0x000055b246c0f867 llvm::sys::CleanupOnSignal(unsigned long)
(/home/david/llvm/build/bin/clang+++0x31f1867)
#3 0x000055b246b8aa5e (anonymous
namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long)
(/home/david/llvm/build/bin/clang+++0x316ca5e)
#4 0x000055b246b8ac04 CrashRecoverySignalHandler(int)
(/home/david/llvm/build/bin/clang+++0x316cc04)
#5 0x00007f0ce1b19930 __restore_rt (/usr/lib/libpthread.so.0+0x14930)
#6 0x00007f0ce1594f25 raise (/usr/lib/libc.so.6+0x3bf25)
#7 0x00007f0ce157e897 abort (/usr/lib/libc.so.6+0x25897)
#8 0x00007f0ce157e767 _nl_load_domain.cold (/usr/lib/libc.so.6+0x25767)
#9 0x00007f0ce158d526 (/usr/lib/libc.so.6+0x34526)
#10 0x000055b249357c27 clang::Expr::EvaluateAsRValue(clang::Expr::EvalResult&,
clang::ASTContext const&, bool) const
(/home/david/llvm/build/bin/clang+++0x5939c27)
#11 0x000055b2489720f5 bool
calculateConstraintSatisfaction<calculateConstraintSatisfaction(clang::Sema&,
clang::NamedDecl const*, llvm::ArrayRef<clang::TemplateArgument>,
clang::SourceLocation, clang::MultiLevelTemplateArgumentList&, clang::Expr
const*, clang::ConstraintSatisfaction&)::$_5>(clang::Sema&, clang::Expr const*,
clang::ConstraintSatisfaction&, calculateConstraintSatisfaction(clang::Sema&,
clang::NamedDecl const*, llvm::ArrayRef<clang::TemplateArgument>,
clang::SourceLocation, clang::MultiLevelTemplateArgumentList&, clang::Expr
const*, clang::ConstraintSatisfaction&)::$_5&&)
(/home/david/llvm/build/bin/clang+++0x4f540f5)
#12 0x000055b24896cd6a
clang::Sema::CheckConstraintSatisfaction(clang::NamedDecl const*,
llvm::ArrayRef<clang::Expr const*>, llvm::ArrayRef<clang::TemplateArgument>,
clang::SourceRange, clang::ConstraintSatisfaction&)
(/home/david/llvm/build/bin/clang+++0x4f4ed6a)
#13 0x000055b248ebea9a clang::Sema::CheckConceptTemplateId(clang::CXXScopeSpec
const&, clang::SourceLocation, clang::DeclarationNameInfo const&,
clang::NamedDecl*, clang::ConceptDecl*, clang::TemplateArgumentListInfo const*)
(/home/david/llvm/build/bin/clang+++0x54a0a9a)
#14 0x000055b248ebed6c clang::Sema::BuildTemplateIdExpr(clang::CXXScopeSpec
const&, clang::SourceLocation, clang::LookupResult&, bool,
clang::TemplateArgumentListInfo const*)
(/home/david/llvm/build/bin/clang+++0x54a0d6c)
#15 0x000055b248b84a6e clang::Sema::ActOnIdExpression(clang::Scope*,
clang::CXXScopeSpec&, clang::SourceLocation, clang::UnqualifiedId&, bool, bool,
clang::CorrectionCandidateCallback*, bool, clang::Token*)
(/home/david/llvm/build/bin/clang+++0x5166a6e)
#16 0x000055b2487b8894
clang::Parser::tryParseCXXIdExpression(clang::CXXScopeSpec&, bool,
clang::Token&) (/home/david/llvm/build/bin/clang+++0x4d9a894)
#17 0x000055b2487b9c6c clang::Parser::ParseCXXIdExpression(bool)
(/home/david/llvm/build/bin/clang+++0x4d9bc6c)
#18 0x000055b2487cb17d
clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&,
clang::Parser::TypeCastState, bool, bool*)
(/home/david/llvm/build/bin/clang+++0x4dad17d)
#19 0x000055b2487cbec7
clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&,
clang::Parser::TypeCastState, bool, bool*)
(/home/david/llvm/build/bin/clang+++0x4dadec7)
#20 0x000055b2487c9513
clang::Parser::ParseConstantExpressionInExprEvalContext(clang::Parser::TypeCastState)
(/home/david/llvm/build/bin/clang+++0x4dab513)
#21 0x000055b248779a5a
clang::Parser::ParseStaticAssertDeclaration(clang::SourceLocation&)
(/home/david/llvm/build/bin/clang+++0x4d5ba5a)
#22 0x000055b248797554
clang::Parser::ParseDeclaration(clang::DeclaratorContext,
clang::SourceLocation&, clang::Parser::ParsedAttributesWithRange&,
clang::SourceLocation*) (/home/david/llvm/build/bin/clang+++0x4d79554)
#23 0x000055b24876b5cf
clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&,
clang::ParsingDeclSpec*) (/home/david/llvm/build/bin/clang+++0x4d4d5cf)
#24 0x000055b248769d37
clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, bool)
(/home/david/llvm/build/bin/clang+++0x4d4bd37)
#25 0x000055b248764f6d clang::ParseAST(clang::Sema&, bool, bool)
(/home/david/llvm/build/bin/clang+++0x4d46f6d)
#26 0x000055b24764a594 clang::CodeGenAction::ExecuteAction()
(/home/david/llvm/build/bin/clang+++0x3c2c594)
#27 0x000055b24758a9c6 clang::FrontendAction::Execute()
(/home/david/llvm/build/bin/clang+++0x3b6c9c6)
#28 0x000055b2474dd7f3
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
(/home/david/llvm/build/bin/clang+++0x3abf7f3)
#29 0x000055b247645078
clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
(/home/david/llvm/build/bin/clang+++0x3c27078)
#30 0x000055b245b594ff cc1_main(llvm::ArrayRef<char const*>, char const*,
void*) (/home/david/llvm/build/bin/clang+++0x213b4ff)
#31 0x000055b245b5748d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&)
(/home/david/llvm/build/bin/clang+++0x213948d)
#32 0x000055b24738f532 void llvm::function_ref<void
()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
<span class="quote">>, std::__cxx11::basic_string<char, std::char_traits<char>,</span >
std::allocator<char> >*, bool*) const::$_1>(long)
(/home/david/llvm/build/bin/clang+++0x3971532)
#33 0x000055b246b8a9aa
llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>)
(/home/david/llvm/build/bin/clang+++0x316c9aa)
#34 0x000055b24738e995
clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>
<span class="quote">>, std::__cxx11::basic_string<char, std::char_traits<char>,</span >
std::allocator<char> >*, bool*) const
(/home/david/llvm/build/bin/clang+++0x3970995)
#35 0x000055b24735922b
clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&,
clang::driver::Command const*&) const
(/home/david/llvm/build/bin/clang+++0x393b22b)
#36 0x000055b24735967a
clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&,
llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const
(/home/david/llvm/build/bin/clang+++0x393b67a)
#37 0x000055b247371c17
clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&,
llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&)
(/home/david/llvm/build/bin/clang+++0x3953c17)
#38 0x000055b245b56bf7 main (/home/david/llvm/build/bin/clang+++0x2138bf7)
#39 0x00007f0ce1580153 __libc_start_main (/usr/lib/libc.so.6+0x27153)
#40 0x000055b245b5402e _start (/home/david/llvm/build/bin/clang+++0x213602e)
clang++: /home/david/llvm/clang/lib/Parse/Parser.cpp:444: virtual
clang::Parser::~Parser(): Assertion `TemplateIds.empty() && "Still alive
TemplateIdAnnotations around?"' failed.
Compiler returned: -1
```</pre>
</div>
</p>
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