Class explicit-instantiation-definition tries to instantiate member functions disabled with `requires`

[HolyBlackCat]

When explicitly instantiating a class, Clang tries to instantiate all member functions, even those that should be disabled with requires. Example:

template <typename T>
struct A
{
    void foo() requires requires{ T::bar(); }
    {
        T::bar();
    }
};

template struct A<int>;

This should compile, but doesn't:

<source>:6:9: error: type 'int' cannot be used prior to '::' because it has no members
        T::bar();
        ^
<source>:10:17: note: in instantiation of member function 'A<int>::foo' requested here
template struct A<int>;
                ^

[royjacobson]

Duplicate of #46029. Checking constraints for class/struct templates was fixed in https://reviews.llvm.org/D120255.

[llvmbot]

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