--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/SemaTemplate/default-arguments.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,231 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+template<typename T, int N = 2> struct X; // expected-note{{template is declared here}}
+
+X<int, 1> *x1;
+X<int> *x2;
+
+X<> *x3; // expected-error{{too few template arguments for class template 'X'}}
+
+template<typename U = float, int M> struct X;
+
+X<> *x4;
+
+template<typename T = int> struct Z { };
+template struct Z<>;
+
+// PR4362
+template<class T> struct a { };
+template<> struct a<int> { static const bool v = true; };
+
+template<class T, bool = a<T>::v> struct p { }; // expected-error {{no member named 'v'}}
+
+template struct p<bool>; // expected-note {{in instantiation of default argument for 'p<bool>' required here}}
+template struct p<int>;
+
+// PR5187
+template<typename T, typename U>
+struct A;
+
+template<typename T, typename U = T>
+struct A;
+
+template<typename T, typename U>
+struct A {
+  void f(A<T>);
+};
+
+template<typename T>
+struct B { };
+
+template<>
+struct B<void> {
+  typedef B<void*> type;
+};
+
+// Nested default arguments for template parameters.
+template<typename T> struct X1 { };
+
+template<typename T>
+struct X2 {
+  template<typename U = typename X1<T>::type> // expected-error{{no type named 'type' in 'X1<int>'}} \
+                                              // expected-error{{no type named 'type' in 'X1<char>'}}
+  struct Inner1 { }; // expected-note{{template is declared here}}
+  
+  template<T Value = X1<T>::value> // expected-error{{no member named 'value' in 'X1<int>'}} \
+                                   // expected-error{{no member named 'value' in 'X1<char>'}}
+  struct NonType1 { }; // expected-note{{template is declared here}}
+  
+  template<T Value>
+  struct Inner2 { };
+  
+  template<typename U>
+  struct Inner3 {
+    template<typename X = T, typename V = U>
+    struct VeryInner { };
+    
+    template<T Value1 = sizeof(T), T Value2 = sizeof(U), 
+             T Value3 = Value1 + Value2>
+    struct NonType2 { };
+  };
+};
+
+X2<int> x2i; // expected-note{{in instantiation of template class 'X2<int>' requested here}}
+X2<int>::Inner1<float> x2iif;
+
+X2<int>::Inner1<> x2bad; // expected-error{{too few template arguments for class template 'Inner1'}}
+
+X2<int>::NonType1<'a'> x2_nontype1;
+X2<int>::NonType1<> x2_nontype1_bad; // expected-error{{too few template arguments for class template 'NonType1'}}
+
+// Check multi-level substitution into template type arguments
+X2<int>::Inner3<float>::VeryInner<> vi;
+X2<char>::Inner3<int>::NonType2<> x2_deep_nontype; // expected-note{{in instantiation of template class 'X2<char>' requested here}}
+
+template<typename T, typename U>
+struct is_same { static const bool value = false; };
+
+template<typename T>
+struct is_same<T, T> { static const bool value = true; };
+
+int array1[is_same<__typeof__(vi), 
+               X2<int>::Inner3<float>::VeryInner<int, float> >::value? 1 : -1];
+
+int array2[is_same<__typeof(x2_deep_nontype),
+                   X2<char>::Inner3<int>::NonType2<sizeof(char), sizeof(int), 
+                                    sizeof(char)+sizeof(int)> >::value? 1 : -1];
+
+// Template template parameter defaults
+template<template<typename T> class X = X2> struct X3 { };
+int array3[is_same<X3<>, X3<X2> >::value? 1 : -1];
+
+struct add_pointer {
+  template<typename T>
+  struct apply {
+    typedef T* type;
+  };
+};
+
+template<typename T, template<typename> class X = T::template apply>
+  struct X4;
+int array4[is_same<X4<add_pointer>, 
+                   X4<add_pointer, add_pointer::apply> >::value? 1 : -1];
+
+template<int> struct X5 {}; // expected-note{{has a different type 'int'}}
+template<long> struct X5b {};
+template<typename T, 
+         template<T> class B = X5> // expected-error{{template template argument has different}} \
+                                   // expected-note{{previous non-type template parameter}}
+  struct X6 {};
+
+X6<int> x6a;
+X6<long> x6b; // expected-note{{while checking a default template argument}}
+X6<long, X5b> x6c;
+
+
+template<template<class> class X = B<int> > struct X7; // expected-error{{must be a class template}}
+
+namespace PR9643 {
+  template<typename T> class allocator {};
+  template<typename T, typename U = allocator<T> > class vector {};
+
+  template<template<typename U, typename = allocator<U> > class container,
+           typename DT>
+  container<DT> initializer(const DT& d) {
+    return container<DT>();
+  }
+
+  void f() {
+    vector<int, allocator<int> > v = initializer<vector>(5);
+  }
+}
+
+namespace PR16288 {
+  template<typename X>
+  struct S {
+    template<typename T = int, typename U>
+#if __cplusplus <= 199711L // C++03 or earlier modes
+    // expected-warning@-2 {{default template arguments for a function template are a C++11 extension}}
+#endif
+    void f();
+  };
+  template<typename X>
+  template<typename T, typename U>
+  void S<X>::f() {}
+}
+
+namespace DR1635 {
+  template <class T> struct X {
+    template <class U = typename T::type> static void f(int) {} // expected-error {{type 'int' cannot be used prior to '::' because it has no members}}
+#if __cplusplus <= 199711L // C++03 or earlier modes
+    // expected-warning@-2 {{default template arguments for a function template are a C++11 extension}}
+#endif
+    static void f(...) {}
+  };
+
+  int g() { X<int>::f(0); } // expected-note {{in instantiation of template class 'DR1635::X<int>' requested here}}
+}
+
+namespace NondefDecls {
+  template<typename T> void f1() {
+    int g1(int defarg = T::error);  // expected-error{{type 'int' cannot be used prior to '::' because it has no members}}
+  }
+  template void f1<int>();  // expected-note{{in instantiation of function template specialization 'NondefDecls::f1<int>' requested here}}
+}
+
+template <typename T>
+struct C {
+  C(T t = ); // expected-error {{expected expression}}
+};
+C<int> obj;
+
+namespace PR26134 {
+// Make sure when substituting default template arguments we do it in the current context.
+template<class T, bool Val = T::value>
+struct X {};
+
+template<bool B> struct Y {
+  void f() { X<Y> xy; }
+  static const bool value = B;
+};
+
+namespace ns1 {
+template<class T0>
+struct X {
+  template<bool B = T0::value> struct XInner { static const bool value = B; };
+};
+template<bool B> struct S { static const bool value = B; };
+#if __cplusplus > 199711L
+template<bool B> struct Y {
+  static constexpr bool f() { return typename X<S<B>>::template XInner<>{}.value; }
+  static_assert(f() == B, "");
+};
+Y<true> y;
+Y<false> y2;
+#endif
+
+} // end ns1
+} // end ns PR26134
+
+namespace friends {
+  namespace ns {
+    template<typename> struct A {
+      template<typename> friend void f();
+      template<typename> friend struct X;
+    };
+    template<typename = int> void f(); // expected-warning 0-1{{extension}}
+    template<typename = int> struct X;
+    A<int> a;
+  }
+  namespace ns {
+    void g() { f(); }
+    X<int> *p;
+  }
+}
+
+namespace unevaluated {
+  int a;
+  template<int = 0> int f(int = a); // expected-warning 0-1{{extension}}
+  int k = sizeof(f());
+}