<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/135012>135012</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Emitting attribute diagnostics twice in some template instantiations
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            c++,
            clang:frontend,
            quality-of-implementation
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          AaronBallman
      </td>
    </tr>
</table>

<pre>
    Consider the following:
```
template <class T>
void f(T __attribute__((align_value(4))) x) {} // expected-warning 2 {{'align_value' attribute only applies to a pointer or reference ('int' is invalid)}}

void foo() {
  f<int>(0); // expected-note {{while substituting explicitly-specified template arguments into function template 'f'}} \
 expected-note {{while substituting deduced template arguments into function template 'f' [with T = int]}}
}
```
It would be ideal to only diagnose once rather than twice. We get one diagnostic from explicit template arguments and another one for deduced template arguments, which seems silly.
</pre>
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