<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/62053>62053</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Access controls checked incorrectly for member classes declared in templated subclasses
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    The following code compiles in GCC and MSVC, but not Clang:
```
#include <type_traits>

class Base {
 protected:
  Base(int i);
};

template <typename U>
class Derived : public Base {
 public:
  template <typename T, typename = void>
  struct ConstructsBase : std::false_type {};

  template <typename T>
  struct ConstructsBase<
      T, std::void_t<decltype(Base(std::declval<T>()))>>
      : std::true_type {};
};

void foo() {
  static_assert(!Derived<const int&>::ConstructsBase<const int>::value);
}
```

(See https://godbolt.org/z/nP795M9qc )

Apparently the template argument list for `ConstructsBase` is evaluated in a context with access to `Base`'s protected constructors, which seems slightly surprising, since `ConstructsBase` isn't itself a subclass of `Base`.

More surprisingly, if `Derived` is made a non-templated class, this works correctly.
</pre>
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