<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 - [concepts] error: out-of-line definition of 'length' from class 'utf_t<type-parameter-0-0>' without definition"
href="https://bugs.llvm.org/show_bug.cgi?id=50276">50276</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[concepts] error: out-of-line definition of 'length' from class 'utf_t<type-parameter-0-0>' without 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>Windows NT
</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>heavenandhell171@gmail.com
</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>$ cat utf.cpp
#include <concepts>
template <typename>
struct utf_t;
template <typename T>
requires (std::is_same_v<T, char32_t>) ||
(std::is_same_v<T, wchar_t> && sizeof(wchar_t) ==
sizeof(char32_t))
struct utf_t<T> {
utf_t() {
}
template <typename Input>
static auto length(Input begin, Input const end) -> unsigned;
};
template <typename T>
requires (std::is_same_v<T, char32_t>) ||
(std::is_same_v<T, wchar_t> && sizeof(wchar_t) ==
sizeof(char32_t))
template <typename Input>
inline auto utf_t<T>::length(Input begin, Input const end) -> unsigned {
return 0;
}
$ clang++ -std=c++20 utf.cpp
utf.cpp:21:23: error: out-of-line definition of 'length' from class
'utf_t<type-parameter-0-0>' without definition
inline auto utf_t<T>::length(Input begin, Input const end) -> unsigned {
~~~~~~~~~~^
1 error generated.
No matter how you constrain it, it doesn't work:
<a href="https://godbolt.org/z/qqaM89nTx">https://godbolt.org/z/qqaM89nTx</a>
GCC compiles it without any error: <a href="https://godbolt.org/z/PM3seoYvW">https://godbolt.org/z/PM3seoYvW</a></pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>