--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/SemaTemplate/current-instantiation.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,249 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// This test concerns the identity of dependent types within the
+// canonical type system, specifically focusing on the difference
+// between members of the current instantiation and members of an
+// unknown specialization. This considers C++ [temp.type], which
+// specifies type equivalence within a template, and C++0x
+// [temp.dep.type], which defines what it means to be a member of the
+// current instantiation.
+
+template<typename T, typename U>
+struct X0 {
+  typedef T T_type;
+  typedef U U_type;
+
+  void f0(T&); // expected-note{{previous}}
+  void f0(typename X0::U_type&);
+  void f0(typename X0::T_type&); // expected-error{{redecl}}
+
+  void f1(T&); // expected-note{{previous}}
+  void f1(typename X0::U_type&);
+  void f1(typename X0<T, U>::T_type&); // expected-error{{redecl}}
+
+  void f2(T&); // expected-note{{previous}}
+  void f2(typename X0::U_type&);
+  void f2(typename X0<T_type, U_type>::T_type&); // expected-error{{redecl}}
+
+  void f3(T&); // expected-note{{previous}}
+  void f3(typename X0::U_type&);
+  void f3(typename ::X0<T_type, U_type>::T_type&); // expected-error{{redecl}}
+
+  struct X1 {
+    typedef T my_T_type;
+
+    void g0(T&); // expected-note{{previous}}
+    void g0(typename X0::U_type&);
+    void g0(typename X0::T_type&); // expected-error{{redecl}}
+
+    void g1(T&); // expected-note{{previous}}
+    void g1(typename X0::U_type&);
+    void g1(typename X0<T, U>::T_type&); // expected-error{{redecl}}
+    
+    void g2(T&); // expected-note{{previous}}
+    void g2(typename X0::U_type&);
+    void g2(typename X0<T_type, U_type>::T_type&); // expected-error{{redecl}}
+    
+    void g3(T&); // expected-note{{previous}}
+    void g3(typename X0::U_type&);
+    void g3(typename ::X0<T_type, U_type>::T_type&); // expected-error{{redecl}}
+
+    void g4(T&); // expected-note{{previous}}
+    void g4(typename X0::U_type&);
+    void g4(typename X1::my_T_type&); // expected-error{{redecl}}
+
+    void g5(T&); // expected-note{{previous}}
+    void g5(typename X0::U_type&);
+    void g5(typename X0::X1::my_T_type&); // expected-error{{redecl}}
+
+    void g6(T&); // expected-note{{previous}}
+    void g6(typename X0::U_type&);
+    void g6(typename X0<T, U>::X1::my_T_type&); // expected-error{{redecl}}
+
+    void g7(T&); // expected-note{{previous}}
+    void g7(typename X0::U_type&);
+    void g7(typename ::X0<typename X1::my_T_type, U_type>::X1::my_T_type&); // expected-error{{redecl}}
+
+    void g8(T&); // expected-note{{previous}}
+    void g8(typename X0<U, T_type>::T_type&);
+    void g8(typename ::X0<typename X0<T_type, U>::X1::my_T_type, U_type>::X1::my_T_type&); // expected-error{{redecl}}
+  };
+};
+
+
+template<typename T, typename U>
+struct X0<T*, U*> {
+  typedef T T_type;
+  typedef U U_type;
+  typedef T* Tptr;
+  typedef U* Uptr;
+  
+  void f0(T&); // expected-note{{previous}}
+  void f0(typename X0::U_type&);
+  void f0(typename X0::T_type&); // expected-error{{redecl}}
+  
+  void f1(T&); // expected-note{{previous}}
+  void f1(typename X0::U_type&);
+  void f1(typename X0<T*, U*>::T_type&); // expected-error{{redecl}}
+  
+  void f2(T&); // expected-note{{previous}}
+  void f2(typename X0::U_type&);
+  void f2(typename X0<T_type*, U_type*>::T_type&); // expected-error{{redecl}}
+  
+  void f3(T&); // expected-note{{previous}}
+  void f3(typename X0::U_type&);
+  void f3(typename ::X0<T_type*, U_type*>::T_type&); // expected-error{{redecl}}
+
+  void f4(T&); // expected-note{{previous}}
+  void f4(typename X0::U_type&);
+  void f4(typename ::X0<Tptr, Uptr>::T_type&); // expected-error{{redecl}}
+  
+  void f5(X0*); // expected-note{{previous}}
+  void f5(::X0<T, U>*);
+  void f5(::X0<T*, U*>*); // expected-error{{redecl}}
+  
+  struct X2 {
+    typedef T my_T_type;
+    
+    void g0(T&); // expected-note{{previous}}
+    void g0(typename X0::U_type&);
+    void g0(typename X0::T_type&); // expected-error{{redecl}}
+    
+    void g1(T&); // expected-note{{previous}}
+    void g1(typename X0::U_type&);
+    void g1(typename X0<T*, U*>::T_type&); // expected-error{{redecl}}
+    
+    void g2(T&); // expected-note{{previous}}
+    void g2(typename X0::U_type&);
+    void g2(typename X0<T_type*, U_type*>::T_type&); // expected-error{{redecl}}
+    
+    void g3(T&); // expected-note{{previous}}
+    void g3(typename X0::U_type&);
+    void g3(typename ::X0<T_type*, U_type*>::T_type&); // expected-error{{redecl}}
+    
+    void g4(T&); // expected-note{{previous}}
+    void g4(typename X0::U_type&);
+    void g4(typename X2::my_T_type&); // expected-error{{redecl}}
+    
+    void g5(T&); // expected-note{{previous}}
+    void g5(typename X0::U_type&);
+    void g5(typename X0::X2::my_T_type&); // expected-error{{redecl}}
+    
+    void g6(T&); // expected-note{{previous}}
+    void g6(typename X0::U_type&);
+    void g6(typename X0<T*, U*>::X2::my_T_type&); // expected-error{{redecl}}
+    
+    void g7(T&); // expected-note{{previous}}
+    void g7(typename X0::U_type&);
+    void g7(typename ::X0<typename X2::my_T_type*, U_type*>::X2::my_T_type&); // expected-error{{redecl}}
+    
+    void g8(T&); // expected-note{{previous}}
+    void g8(typename X0<U, T_type>::T_type&);
+    void g8(typename ::X0<typename X0<T_type*, U*>::X2::my_T_type*, U_type*>::X2::my_T_type&); // expected-error{{redecl}}
+  };
+};
+
+template<typename T>
+struct X1 {
+  static int *a;
+  void f(float *b) {
+    X1<T>::a = b; // expected-error{{incompatible}}
+    X1<T*>::a = b;
+  }
+};
+
+namespace ConstantInCurrentInstantiation {
+  template<typename T>
+  struct X {
+    static const int value = 2;
+    static int array[value];
+  };
+
+  template<typename T> const int X<T>::value;
+
+  template<typename T>
+  int X<T>::array[X<T>::value] = { 1, 2 };
+}
+
+namespace Expressions {
+  template <bool b>
+  struct Bool {
+    enum anonymous_enum { value = b };
+  };
+  struct True : public Bool<true> {};
+  struct False : public Bool<false> {};
+
+  template <typename T1, typename T2>
+  struct Is_Same : public False {};
+  template <typename T>
+  struct Is_Same<T, T> : public True {};
+
+  template <bool b, typename T = void>
+  struct Enable_If {};
+  template <typename T>
+  struct Enable_If<true, T>  {
+    typedef T type;
+  };
+
+  template <typename T>
+  class Class {
+  public:
+    template <typename U>
+    typename Enable_If<Is_Same<U, Class>::value, void>::type
+    foo();
+  };
+
+
+  template <typename T>
+  template <typename U>
+  typename Enable_If<Is_Same<U, Class<T> >::value, void>::type
+  Class<T>::foo() {}
+}
+
+namespace PR9255 {
+  template<typename T>
+  class X0  {
+  public:
+    class Inner1;
+
+    class Inner2  {
+    public:
+      void f()
+      {
+        Inner1::f.g();
+      }
+    };
+  };
+}
+
+namespace rdar10194295 {
+  template<typename XT>
+  class X {
+  public:
+    enum Enum { Yes, No };
+    template<Enum> void foo();
+    template<Enum> class Inner;
+  };
+
+  template<typename XT>
+  template<typename X<XT>::Enum>
+  void X<XT>::foo()
+  {
+  }
+
+  template<typename XT>
+  template<typename X<XT>::Enum>
+  class X<XT>::Inner { };
+}
+
+namespace RebuildDependentScopeDeclRefExpr {
+  template<int> struct N {};
+  template<typename T> struct X {
+    static const int thing = 0;
+    N<thing> data();
+    N<thing> foo();
+  };
+  template<typename T> N<X<T>::thing> X<T>::data() {}
+  // FIXME: We should issue a typo-correction here.
+  template<typename T> N<X<T>::think> X<T>::foo() {} // expected-error {{no member named 'think' in 'X<T>'}}
+}