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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang reports an error：out-of-line definition of 'f' does not match any declaration"
href="https://bugs.llvm.org/show_bug.cgi?id=47358">47358</a>
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<th>Summary</th>
<td>clang reports an error：out-of-line definition of 'f' does not match any declaration
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++2a
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>tangyixuan@mail.dlut.edu.cn
</td>
</tr>
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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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<p>
<div>
<pre>The following code is accepted by g++ with -std=c++2a, while is rejected by
clang++.
$ cat s.cpp
#include <concepts>
template <typename T>
class A
{
using type = int;
template <typename U>
requires std::same_as<type, U>
void f();
};
template <typename T>
template <typename U>
requires std::same_as<typename A<T>::type, U>
void A<T>::f(){}
$ g++ -c -std=c++2a s.cpp
success.
$ clang -v
clang version 11.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
ab4627364aefcaac751e757b721b7d07b48a545a)
Target: x86_64-unknown-linux-gnu
Thread model: posix
$ clang++ -c -std=c++2a s.cpp
s.cpp:16:12: error: out-of-line definition of 'f' does not match any
declaration in 'A<T>'
void A<T>::f(){}
^
1 error generated.</pre>
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