<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/121924>121924</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang allows template constructor to have different template argument list with that of class definition with default argument
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          wangbo15
      </td>
    </tr>
</table>

<pre>
    The following invalid code is not rejected by clang for an incompatible template parameter list between ctor and class definition:

```c++
template <class TClass, int NON=0> 
class T 
{ 
public: 
  T<TClass>(int f) {}
}; 

int main(){
    T<int> t(10);
}
```

EDG and GCC reject it. The diagnostic of GCC is somewhat weird though.

EDG rejects it with the following diagnostic, which seems more reasonable.

```c++
"<source>", line 5: error: type used as constructor name does not match type "T<TClass, NON>"
    T<TClass>(int f) {}
    ^

1 error detected in the compilation of "<source>".
```

Please see https://godbolt.org/z/s3KK85qxo
</pre>
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