test/SemaTemplate/deduction.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s
   2
   3 // Template argument deduction with template template parameters.
   4 template<typename T, template<T> class A>
   5 struct X0 {
   6   static const unsigned value = 0;
   7 };
   8
   9 template<template<int> class A>
  10 struct X0<int, A> {
  11   static const unsigned value = 1;
  12 };
  13
  14 template<int> struct X0i;
  15 template<long> struct X0l;
  16 int array_x0a[X0<long, X0l>::value == 0? 1 : -1];
  17 int array_x0b[X0<int, X0i>::value == 1? 1 : -1];
  18
  19 template<typename T, typename U>
  20 struct is_same {
  21   static const bool value = false;
  22 };
  23
  24 template<typename T>
  25 struct is_same<T, T> {
  26   static const bool value = true;
  27 };
  28
  29 template<typename T> struct allocator { };
  30 template<typename T, typename Alloc = allocator<T> > struct vector {};
  31
  32 // Fun with meta-lambdas!
  33 struct _1 {};
  34 struct _2 {};
  35
  36 // Replaces all occurrences of _1 with Arg1 and _2 with Arg2 in T.
  37 template<typename T, typename Arg1, typename Arg2>
  38 struct Replace {
  39   typedef T type;
  40 };
  41
  42 // Replacement of the whole type.
  43 template<typename Arg1, typename Arg2>
  44 struct Replace<_1, Arg1, Arg2> {
  45   typedef Arg1 type;
  46 };
  47
  48 template<typename Arg1, typename Arg2>
  49 struct Replace<_2, Arg1, Arg2> {
  50   typedef Arg2 type;
  51 };
  52
  53 // Replacement through cv-qualifiers
  54 template<typename T, typename Arg1, typename Arg2>
  55 struct Replace<const T, Arg1, Arg2> {
  56   typedef typename Replace<T, Arg1, Arg2>::type const type;
  57 };
  58
  59 // Replacement of templates
  60 template<template<typename> class TT, typename T1, typename Arg1, typename Arg2>
  61 struct Replace<TT<T1>, Arg1, Arg2> {
  62   typedef TT<typename Replace<T1, Arg1, Arg2>::type> type;
  63 };
  64
  65 template<template<typename, typename> class TT, typename T1, typename T2,
  66          typename Arg1, typename Arg2>
  67 struct Replace<TT<T1, T2>, Arg1, Arg2> {
  68   typedef TT<typename Replace<T1, Arg1, Arg2>::type,
  69              typename Replace<T2, Arg1, Arg2>::type> type;
  70 };
  71
  72 // Just for kicks...
  73 template<template<typename, typename> class TT, typename T1,
  74          typename Arg1, typename Arg2>
  75 struct Replace<TT<T1, _2>, Arg1, Arg2> {
  76   typedef TT<typename Replace<T1, Arg1, Arg2>::type, Arg2> type;
  77 };
  78
  79 int array0[is_same<Replace<_1, int, float>::type, int>::value? 1 : -1];
  80 int array1[is_same<Replace<const _1, int, float>::type, const int>::value? 1 : -1];
  81 int array2[is_same<Replace<vector<_1>, int, float>::type, vector<int> >::value? 1 : -1];
  82 int array3[is_same<Replace<vector<const _1>, int, float>::type, vector<const int> >::value? 1 : -1];
  83 int array4[is_same<Replace<vector<int, _2>, double, float>::type, vector<int, float> >::value? 1 : -1];
  84
  85 // PR5911
  86 template <typename T, int N> void f(const T (&a)[N]);
  87 int iarr[] = { 1 };
  88 void test_PR5911() { f(iarr); }
  89
  90 // Must not examine base classes of incomplete type during template argument
  91 // deduction.
  92 namespace PR6257 {
  93   template <typename T> struct X {
  94     template <typename U> X(const X<U>& u);
  95   };
  96   struct A;
  97   void f(A& a);
  98   void f(const X<A>& a);
  99   void test(A& a) { (void)f(a); }
 100 }
 101
 102 // PR7463
 103 namespace PR7463 {
 104   const int f ();
 105   template <typename T_> void g (T_&); // expected-note{{T_ = int}}
 106   void h (void) { g(f()); } // expected-error{{no matching function for call}}
 107 }
 108
 109 namespace test0 {
 110   template <class T> void make(const T *(*fn)()); // expected-note {{candidate template ignored: can't deduce a type for 'T' which would make 'const T' equal 'char'}}
 111   char *char_maker();
 112   void test() {
 113     make(char_maker); // expected-error {{no matching function for call to 'make'}}
 114   }
 115 }
 116
 117 namespace test1 {
 118   template<typename T> void foo(const T a[3][3]);
 119   void test() {
 120     int a[3][3];
 121     foo(a);
 122   }
 123 }
 124
 125 // PR7708
 126 namespace test2 {
 127   template<typename T> struct Const { typedef void const type; };
 128
 129   template<typename T> void f(T, typename Const<T>::type*);
 130   template<typename T> void f(T, void const *);
 131
 132   void test() {
 133     void *p = 0;
 134     f(0, p);
 135   }
 136 }
 137
 138 // rdar://problem/8537391
 139 namespace test3 {
 140   struct Foo {
 141     template <void F(char)> static inline void foo();
 142   };
 143
 144   class Bar {
 145     template<typename T> static inline void wobble(T ch);
 146
 147   public:
 148     static void madness() {
 149       Foo::foo<wobble<char> >();
 150     }
 151   };
 152 }