In some contexts, decltype(&(C::member)) yields a pointer to member type, but according to [expr.unary.op]/4, no pointer to member should be formed when the operand of the & operator is enclosed in parentheses. http://eel.is/c++draft/expr.unary.op#4 The code below demonstrates this behavior. It compiles on all Clang versions I have tried between 3.2 and HEAD, even though I don't think it should. ``` #include <type_traits> struct S { int x; static_assert(std::is_same<decltype(&(S::x)), int S::*>::value, ""); // ! void foo() { static_assert(std::is_same<decltype(&(S::x)), int*>::value, ""); // OK } }; static_assert(std::is_same<decltype(&(S::x)), int S::*>::value, ""); // ! int main() { } ```