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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Reversed candidate operator is not found by argument dependent lookup"
href="https://bugs.llvm.org/show_bug.cgi?id=44627">44627</a>
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<th>Summary</th>
<td>Reversed candidate operator is not found by argument dependent lookup
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++2a
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>david@doublewise.net
</td>
</tr>
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<th>CC</th>
<td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>The following code
```
namespace n {
struct type {};
bool operator==(type lhs, int rhs) {
return true;
}
} // namespace n
void f() {
n::type() == 0;
0 == n::type(); // fails
}
```
fails to compile with the error message
```
<source>:13:7: error: invalid operands to binary expression ('int' and
'n::type')
0 == n::type(); // fails
~ ^ ~~~~~~~~~
<source>:5:6: note: candidate function not viable: no known conversion from
'int' to 'n::type' for 1st argument
bool operator==(type lhs, int rhs) {
^
1 error generated.
Compiler returned: 1
```
when compiled against clang trunk with `clang++ -std=c++2a -stdlib=libc++ -w`.
The same thing occurs for `<=>` and the other comparison operators. Note that
it succeeds if the definition of `f` is moved into `n`.
See it live: <a href="https://godbolt.org/z/pHwvw6">https://godbolt.org/z/pHwvw6</a></pre>
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