<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/56313>56313</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Error with valid defaulted default constructor involving anonymous union
        </td>
    </tr>

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

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

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

<pre>
    Test case:
```
struct A {
   A() { }
};

struct V {
   V() { };
   ~V() { }
};


struct S {
   S();
   ~S() {}

   union {
     A a = {};
     V v;
   };
};

S::S() = default;
```

Result:
```
x.cc:22:4: error: defaulting this default constructor would delete it after its first declaration
S::S() = default;
   ^
```

The error goes away if `= default` is replaced with `{}`.

The error message is incorrect, because none of the items in [class.default.ctor] p2 applies. In particular, p2.2 does not apply because S::a has a default member initializer.

Related gcc bug report: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106150
</pre>
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