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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - __is_trivial doesn't work in the presence of special member functions with trailing requires clauses"
href="https://bugs.llvm.org/show_bug.cgi?id=50740">50740</a>
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<th>Summary</th>
<td>__is_trivial doesn't work in the presence of special member functions with trailing requires clauses
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>trunk
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++2a
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>ldionne@apple.com
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<th>CC</th>
<td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>When compiled with Clang ToT, the following code incorrectly believes that
allocator<void> is non-trivial, when it should be trivial:
cat <<EOF | clang++ -xc++ - -std=c++2a -fsyntax-only
#include <type_traits>
template <class T>
struct allocator {
allocator() = default;
allocator() requires(!std::is_void_v<T>) { }
};
static_assert(__is_trivial(allocator<void>));
int main() { }
EOF
This works on GCC. Godbolt link: <a href="https://godbolt.org/z/4osMGWTne">https://godbolt.org/z/4osMGWTne</a>.
I tracked the issue down a bit, and I think the issue is that when
QualType::isTrivialType() queries whether the class declaration has a
non-trivial default constructor (via
CXXRecordDecl::hasNonTrivialDefaultConstructor()), it incorrectly believes that
it's the case.</pre>
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