Defining a method with a user-defined concept of class template outside its scope gives an error: "out-of-line definition of does not match any declaration in" (original) (raw)

Well, trying to define a method with a user-defined concept of class template outside its scope gives an error:

error: out-of-line definition of '...' does not match any declaration in '...'

GCC, in turn, compiles such code just fine.
https://godbolt.org/z/PTnh6Y4ab