clang fails to find operator `->`

[ahatanak]

struct D {
  template <typename T> void m() {}
};

template <typename T> struct S {
  void init() { (*this)->template m<T>(); };

  D *operator->();
};

clang rejects the code with the following error message:

<source>:6:35: error: no member named 'm' in 'S<T>'
    6 |   void init() { (*this)->template m<T>(); };

It looks like clang's behavior changed after 1595988ee6f9732e7ea79928af8a470ad5ef7dbe.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Akira Hatanaka (ahatanak)

``` struct D { template <typename T> void m() {} };

template <typename T> struct S {
void init() { (*this)->template m<T>(); };

D *operator->();
};

clang rejects the code with the following error message:

<source>:6:35: error: no member named 'm' in 'S<T>'
    6 |   void init() { (*this)->template m<T>(); };

It looks like clang's behavior changed after 1595988ee6f9732e7ea79928af8a470ad5ef7dbe.
</details>

[ahatanak]

@sdkrystian is this expected?

[sdkrystian]

@ahatanak This is rather interesting... we accept this:

struct D {
  template <typename T = 0> void m() {}
};

template <typename T> struct S {
  void init() { (*this)->m(); };

  D *operator->();
};

... but we reject your provided example. I have some ideas as to what is going wrong... I'll investigate tomorrow.

[h-vetinari]

This should probably be reopened, given that 3681d85 reverted #104458