clang/test/SemaCXX/enum-unscoped-nonexistent.cpp

   1 // RUN: %clang_cc1 -std=c++11 -verify %s
   2
   3 struct Base {
   4   static const int a = 1;
   5 };
   6 template<typename T> struct S : Base {
   7   enum E : int;
   8   constexpr int f() const;
   9   constexpr int g() const;
  10   void h();
  11 };
  12 template<> enum S<char>::E : int {}; // expected-note {{enum 'S<char>::E' was explicitly specialized here}}
  13 template<> enum S<short>::E : int { b = 2 };
  14 template<> enum S<int>::E : int { a = 4 };
  15 template<typename T> enum S<T>::E : int { b = 8 };
  16
  17 // The unqualified-id here names a member of the non-dependent base class Base
  18 // and not the injected enumerator name 'a' from the specialization.
  19 template<typename T> constexpr int S<T>::f() const { return a; }
  20 static_assert(S<char>().f() == 1, "");
  21 static_assert(S<int>().f() == 1, "");
  22
  23 // The unqualified-id here names a member of the current instantiation, which
  24 // bizarrely might not exist in some instantiations.
  25 template<typename T> constexpr int S<T>::g() const { return b; } // expected-error {{enumerator 'b' does not exist in instantiation of 'S<char>'}}
  26 static_assert(S<char>().g() == 1, ""); // expected-note {{here}} expected-error {{not an integral constant expression}}
  27 static_assert(S<short>().g() == 2, "");
  28 static_assert(S<long>().g() == 8, "");
  29
  30 // 'b' is type-dependent, so these assertions should not fire before 'h' is
  31 // instantiated.
  32 template<typename T> void S<T>::h() {
  33   char c[S<T>::b];
  34   static_assert(b != 8, "");
  35   static_assert(sizeof(c) != 8, "");
  36 }
  37 void f() {
  38   S<short>().h(); // ok, b == 2
  39 }