[Clang] Unexpected Overloading of Static and Non-Static Member Functions

[16bit-ykiko]

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.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: ykiko (16bit-ykiko)

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.

[zyn0217]

@cor3ntin

llvm-project/clang/lib/Sema/SemaOverload.cpp

Lines 1483 to 1486 in 7a28a5b

	if (OldMethod && NewMethod && !OldMethod->isStatic() &&
	!OldMethod->isStatic()) {
	bool HaveCorrespondingObjectParameters = [&](const CXXMethodDecl *Old,

I suppose this should be !OldMethod->isStatic() && !NewMethod->isStatic()? Otherwise, we would consider the non-static and static as overload functions.

[cor3ntin]

@zyn0217 Probably, yes. Do you plan to make a PR?

[zyn0217]

Not yet; if you're going to have one, please feel free. :)