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<head>
<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Infinite loop during auto return type deduction"
href="https://bugs.llvm.org/show_bug.cgi?id=34742">34742</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Infinite loop during auto return type deduction
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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++11
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>rtrieu@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>The auto return type of a member function depends on its own return value.
When instantiating the function, template deduction recursively tries to deduce
the return type with no end.
$ cat foo.cc
struct S {
template<class X = S>
static auto foo() -> decltype(X::foo());
};
void run() {
S::foo<>();
};
$ clang foo.cc -std=c++11
#0 0x0000000001e191e4 PrintStackTraceSignalHandler(void*)
(/usr/local/bin/clang-
3.5+0x1e191e4)
#1 0x0000000001e19546 SignalHandler(int) (/usr/local/bin/clang-3.5+0x1e19546)
#2 0x00007fcfb4081330 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x1033
0)
#3 0x00000000033736d6 clang::Sema::BuildOverloadedCallExpr(clang::Scope*,
clang:
:Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation,
llvm::MutableArrayR
ef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool)
(/usr/local/b
in/clang-3.5+0x33736d6)
#4 0x000000000315196c clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*,
clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>,
clang::SourceLocation, clang::Expr*, bool) (/usr/local/bin/clang-3.5+0x315196c)
#5 0x000000000349c0ff clang::TreeTransform<(anonymous
namespace)::TemplateInstantiator>::TransformCallExpr(clang::CallExpr*)
(/usr/local/bin/clang-3.5+0x349c0ff)
#6 0x0000000003488c9e clang::TreeTransform<(anonymous
namespace)::TemplateInstantiator>::TransformType(clang::TypeLocBuilder&,
clang::TypeLoc) (/usr/local/bin/clang-3.5+0x3488c9e)
#7 0x000000000348cb99
clang::Sema::SubstFunctionDeclType(clang::TypeSourceInfo*,
clang::MultiLevelTemplateArgumentList const&, clang::SourceLocation,
clang::DeclarationName, clang::CXXRecordDecl*, unsigned int)
(/usr/local/bin/clang-3.5+0x348cb99)
#8 0x00000000034c5bc4
clang::TemplateDeclInstantiator::SubstFunctionType(clang::FunctionDecl*,
llvm::SmallVectorImpl<clang::ParmVarDecl*>&)
(/usr/local/bin/clang-3.5+0x34c5bc4)
#9 0x00000000034c312c
clang::TemplateDeclInstantiator::VisitCXXMethodDecl(clang::CXXMethodDecl*,
clang::TemplateParameterList*, bool) (/usr/local/bin/clang-3.5+0x34c312c)
#10 0x00000000034cab16 clang::Sema::SubstDecl(clang::Decl*,
clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&)
(/usr/local/bin/clang-3.5+0x34cab16)
#11 0x000000000344b4c6
clang::Sema::FinishTemplateArgumentDeduction(clang::FunctionTemplateDecl*,
llvm::SmallVectorImpl<clang::DeducedTemplateArgument>&, unsigned int,
clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&,
llvm::SmallVectorImpl<clang::Sema::OriginalCallArg> const*, bool,
llvm::function_ref<bool ()>) (/usr/local/bin/clang-3.5+0x344b4c6)
#12 0x000000000344cec0
clang::Sema::DeduceTemplateArguments(clang::FunctionTemplateDecl*,
clang::TemplateArgumentListInfo*, llvm::ArrayRef<clang::Expr*>,
clang::FunctionDecl*&, clang::sema::TemplateDeductionInfo&, bool,
llvm::function_ref<bool (llvm::ArrayRef<clang::QualType>)>)
(/usr/local/bin/clang-3.5+0x344cec0)
#13 0x000000000335fc24
clang::Sema::AddTemplateOverloadCandidate(clang::FunctionTemplateDecl*,
clang::DeclAccessPair, clang::TemplateArgumentListInfo*,
llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool)
(/usr/local/bin/clang-3.5+0x335fc24)
#14 0x00000000033731bd AddOverloadedCallCandidate(clang::Sema&,
clang::DeclAccessPair, clang::TemplateArgumentListInfo*,
llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool, bool)
(/usr/local/bin/clang-3.5+0x33731bd)
#15 0x0000000003372fc8
clang::Sema::AddOverloadedCallCandidates(clang::UnresolvedLookupExpr*,
llvm::ArrayRef<clang::Expr*>, clang::OverloadCandidateSet&, bool)
(/usr/local/bin/clang-3.5+0x3372fc8)
#16 0x00000000033733db clang::Sema::buildOverloadedCallSet(clang::Scope*,
clang::Expr*, clang::UnresolvedLookupExpr*,
llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation,
clang::OverloadCandidateSet*, clang::ActionResult<clang::Expr*, true>*)
(/usr/local/bin/clang-3.5+0x33733db)
#17 0x00000000033737ec clang::Sema::BuildOverloadedCallExpr(clang::Scope*,
clang::Expr*, clang::UnresolvedLookupExpr*, clang::SourceLocation,
llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool,
bool) (/usr/local/bin/clang-3.5+0x33737ec)
< Repeat from #4 Sema::ActOnCallExpr ></pre>
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