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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - poor diagnostics for ambiguous template function instantation"
href="https://llvm.org/bugs/show_bug.cgi?id=31450">31450</a>
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</tr>
<tr>
<th>Summary</th>
<td>poor diagnostics for ambiguous template function instantation
</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>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>Frontend
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>compnerd@compnerd.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Consider the following code:
namespace n {
int f(void *);
template <int> int g(void *);
extern template int g<0>(void *);
}
using namespace n;
template <int> int g(void *p) { return 0; }
template int g<0>(void *);
The template function here is ambiguous because we have n::g and ::g.
We diagnose this as:
$ clang -fsyntax-only -std=c++11 /tmp/reduced.cc
/tmp/reduced.cc:13:14: error: partial ordering for explicit instantiation of
'g' is ambiguous
template int g<0>(void *);
^
/tmp/reduced.cc:11:20: note: explicit instantiation candidate function template
here [with $0 = 0]
template <int> int g(void *p) { return 0; }
^
/tmp/reduced.cc:4:20: note: explicit instantiation candidate function template
here [with $0 = 0]
template <int> int g(void *);
^
While gcc diagnoses this as:
$ c++ -fsyntax-only -std=c++11 /tmp/reduced.cc
/tmp/reduced.cc:13:14: error: ambiguous template specialization 'g<0>' for 'int
g(void*)'
template int g<0>(void *);
^
/tmp/reduced.cc:11:20: note: candidates are: template<int <anonymous> > int
g(void*)
template <int> int g(void *p) { return 0; }
^
/tmp/reduced.cc:4:20: note: template<int <anonymous> > int
n::g(void*)
template <int> int g(void *);</pre>
</div>
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