`consteval` constructor cannot store `this` inside object

[snarkmaster]

Unlike GCC & MSVC, Clang refuses to compile this https://godbolt.org/z/WYr58Ge9s --

struct B {
  const void* immortal_;
  consteval B() : immortal_{this} {}
};
constexpr static B b;

The error suggests that the frontend wrongly thinks that this is a pointer to a temporary:

<source>:6:20: error: call to consteval function 'B::B' is not a constant expression
    6 | constexpr static B b;
      |                    ^
<source>:6:20: note: pointer to temporary is not a constant expression
<source>:6:20: note: temporary created here

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (snarkmaster)

Unlike GCC & MSVC, Clang refuses to compile this https://godbolt.org/z/WYr58Ge9s --

struct B {
  const void* immortal_;
  consteval B() : immortal_{this} {}
};
constexpr static B b;

The error suggests that the frontend wrongly thinks that this is a pointer to a temporary:

<source>:6:20: error: call to consteval function 'B::B' is not a constant expression
    6 | constexpr static B b;
      |                    ^
<source>:6:20: note: pointer to temporary is not a constant expression
<source>:6:20: note: temporary created here

[snarkmaster]

Here's a rather gross workaround by adding a bunch of indirection: https://godbolt.org/z/1bhv34Tbn