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<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 - Clang produces less useful error message when explicit constructor invoked implicitly"
href="https://bugs.llvm.org/show_bug.cgi?id=34744">34744</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Clang produces less useful error message when explicit constructor invoked implicitly
</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++
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>csaba_22@yahoo.co.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>$ clang -v
clang version 5.0.0 (trunk 308427)
$ cat errmsg.cpp
#include <string>
#include <map>
namespace a {
struct AV {
explicit AV(std::string const&);
};
// ---
struct EAV;
typedef std::map<std::string, EAV> EAM;
struct EAV {
explicit EAV(AV const&);
};
// ---
struct UIRQ {
typedef EAM ET;
ET const& expected() const;
UIRQ & expected(ET const&);
};
}
int main()
{
a::UIRQ req;
req.expected({ {"kye", a::AV{ "valu" } } });
}
/* GCC 8
errmsg.cpp: In function ‘int main()’:
errmsg.cpp:32:47: error: converting to ‘std::pair<const
std::basic_string<char>, a::EAV>’ from initializer list would use explicit
constructor ‘constexpr std::pair<_T1, _T2>::pair(_U1&&, _U2&&) [with _U1 =
const char (&)[4]; _U2 = a::AV; typename std::enable_if<(std::_PCC<true, _T1,
_T2>::_MoveConstructiblePair<_U1, _U2>() && (! std::_PCC<true, _T1,
_T2>::_ImplicitlyMoveConvertiblePair<_U1, _U2>())), bool>::type <anonymous> =
0; _T1 = const std::basic_string<char>; _T2 = a::EAV]’
req.expected({ {"kye", a::AV{ "valu" } } });
^
*/
/* clang 5.0.0
errmsg.cpp:32:9: error: no matching member function for call to 'expected'
req.expected({ {"kye", a::AV{ "valu" } } });
~~~~^~~~~~~~
errmsg.cpp:25:16: note: candidate function not viable: cannot convert
initializer list argument to 'const a::UIRQ::ET' (aka 'const
map<basic_string<char>, a::EAV>')
UIRQ & expected(ET const&);
^
errmsg.cpp:23:19: note: candidate function not viable: requires 0 arguments,
but 1 was provided
ET const& expected() const;
^
*/
The GCC error message mentions a hint to the problem (EAV constructor is
explicit). Clang's error message makes no mention of 'explicit'.</pre>
</div>
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