xref: /external/clang/test/SemaTemplate/deduction.cpp

// RUN: clang-cc -fsyntax-only %s

// Template argument deduction with template template parameters.
template<typename T, template<T> class A>
struct X0 {
  static const unsigned value = 0;
};

template<template<int> class A>
struct X0<int, A> {
  static const unsigned value = 1;
};

template<int> struct X0i;
template<long> struct X0l;
int array_x0a[X0<long, X0l>::value == 0? 1 : -1];
int array_x0b[X0<int, X0i>::value == 1? 1 : -1];

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;
};

template<typename T> struct allocator { };
template<typename T, typename Alloc = allocator<T> > struct vector {};

// Fun with meta-lambdas!
struct _1 {};
struct _2 {};

// Replaces all occurrences of _1 with Arg1 and _2 with Arg2 in T.
template<typename T, typename Arg1, typename Arg2>
struct Replace {
  typedef T type;
};

// Replacement of the whole type.
template<typename Arg1, typename Arg2>
struct Replace<_1, Arg1, Arg2> {
  typedef Arg1 type;
};

template<typename Arg1, typename Arg2>
struct Replace<_2, Arg1, Arg2> {
  typedef Arg2 type;
};

// Replacement through cv-qualifiers
template<typename T, typename Arg1, typename Arg2>
struct Replace<const T, Arg1, Arg2> {
  typedef typename Replace<T, Arg1, Arg2>::type const type;
};

// Replacement of templates
template<template<typename> class TT, typename T1, typename Arg1, typename Arg2>
struct Replace<TT<T1>, Arg1, Arg2> {
  typedef TT<typename Replace<T1, Arg1, Arg2>::type> type;
};

template<template<typename, typename> class TT, typename T1, typename T2,
         typename Arg1, typename Arg2>
struct Replace<TT<T1, T2>, Arg1, Arg2> {
  typedef TT<typename Replace<T1, Arg1, Arg2>::type,
             typename Replace<T2, Arg1, Arg2>::type> type;
};

// Just for kicks...
template<template<typename, typename> class TT, typename T1,
         typename Arg1, typename Arg2>
struct Replace<TT<T1, _2>, Arg1, Arg2> {
  typedef TT<typename Replace<T1, Arg1, Arg2>::type, Arg2> type;
};

int array0[is_same<Replace<_1, int, float>::type, int>::value? 1 : -1];
int array1[is_same<Replace<const _1, int, float>::type, const int>::value? 1 : -1];
int array2[is_same<Replace<vector<_1>, int, float>::type, vector<int> >::value? 1 : -1];
int array3[is_same<Replace<vector<const _1>, int, float>::type, vector<const int> >::value? 1 : -1];
int array4[is_same<Replace<vector<int, _2>, double, float>::type, vector<int, float> >::value? 1 : -1];