<html>
<head>
<base href="https://llvm.org/bugs/" />
</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 --- - Clang ignores 'explicit' constructors in copy-list-initialization of function argument"
href="https://llvm.org/bugs/show_bug.cgi?id=27642">27642</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Clang ignores 'explicit' constructors in copy-list-initialization of function argument
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</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>ed@catmur.co.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Per N2532=08-0042 (<a href="http://www.stroustrup.com/list-issues-2.pdf">http://www.stroustrup.com/list-issues-2.pdf</a>) chapter 4 the
following program should be rejected as ambiguous:
struct String1 { explicit String1(const char*); };
struct String2 { String2(const char*); };
void f(String1);
void f(String2);
int main() {
f( {"asdf"} ); // error, ambiguous
}
This was confirmed by CWG 1228 (<a href="http://wg21.cmeerw.net/cwg/issue1228">http://wg21.cmeerw.net/cwg/issue1228</a>):
struct MyStore {
explicit MyStore(int initialCapacity);
};
struct MyInt {
MyInt(int i);
};
struct Printer {
void operator()(MyStore const& s);
void operator()(MyInt const& i);
};
void f() {
Printer p;
p({23}); // error, ambiguous
}
gcc (6.1 and preceding versions) correctly rejects both these programs.
I don't like this behavior, but it is what over.match.list prescribes.
Possible follow up to <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Clang ignores 'explicit' constructors in copy-list-initialization"
href="show_bug.cgi?id=12120">bug 12120</a>.
Discussion:
<a href="http://stackoverflow.com/questions/34622076/calling-an-explicit-constructor-with-a-braced-init-list-ambiguous-or-not?rq=1">http://stackoverflow.com/questions/34622076/calling-an-explicit-constructor-with-a-braced-init-list-ambiguous-or-not?rq=1</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>