<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 --- - Wrong number of template arguments with empty parameter pack" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24098&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=sWoJJzp3fAWyYsc-enQ1HZIy5WzU6UFVvO6vNp44ie4&s=Ghoqix69axS86t_1bNxuF8uuKGJvT9UFti7A005STWE&e=">24098</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Wrong number of template arguments with empty parameter pack
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Macintosh
</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>ldionne.2@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following code fails to compile on Clang trunk:
template <typename> struct f;
template <typename ...Dummy, typename = f<int, Dummy...>>
void foo() { }
The error is:
prog.cc:3:53: error: wrong number of template arguments (2, should be 1)
template <typename ...Dummy, typename = f<int, Dummy...>>
^
prog.cc:1:28: note: provided for 'template<class> struct f'
template <typename> struct f;
^
Strangely, the following compiles (swapped `Dummy...` and `int`):
template <typename> struct f;
template <typename ...Dummy, typename = f<Dummy..., int>>
void foo() { }
Live example: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__melpon.org_wandbox_permlink_yrtJAhiue1iDVLR3&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=sWoJJzp3fAWyYsc-enQ1HZIy5WzU6UFVvO6vNp44ie4&s=FUO5KJabGoujJ5Q7KLOezquN-7FnX5TkzcFzaEyXuRc&e=">http://melpon.org/wandbox/permlink/yrtJAhiue1iDVLR3</a>
Note that GCC rejects both examples. Naively, I think both should compile,
but I haven't checked the standard. In all cases, either Clang has a bug,
GCC has a bug or both have a bug.</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>