According to the C++ Standard, static and non-static member functions with the same parameter types cannot be overloaded. The following code should fail to compile.

struct X {
    void f() const;
    static void f();
};

It fails in clang 17, but succeeds in clang 18. And I find it is related to the declaration order. If swap the declaration order of the two functions

struct X {
    static void f();
    void f() const;
};

It fails as expected, please see Compiler Explorer.