I made a generic overload for Enum.HasFlag that prevents boxing:

    public static unsafe bool HasFlag<T>(this T enumVal, T flag) where T : unmanaged, Enum {
        return sizeof(T) switch {
            1 => (*(byte*)&enumVal & *(byte*)&flag) == *(byte*)&flag,
            2 => (*(ushort*)&enumVal & *(ushort*)&flag) == *(ushort*)&flag,
            4 => (*(uint*)&enumVal & *(uint*)&flag) == *(uint*)&flag,
            8 => (*(ulong*)&enumVal & *(ulong*)&flag) == *(ulong*)&flag,
            _ => throw new ArgumentException("Unsupported base enum Type")
        };
    }

Yet the compiler still wants to use the default Enum.HasFlag instead and I have to explicitly define the generic type to force it to use the extension.

The extension method should take priority here as the parameters have the correct type and do not need implicit type casting compared to the original one so why is the compiler still using the wrong one?