reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
  150
  151
  152
  153
  154
  155
  156
  157
  158
  159
  160
  161
  162
  163
  164
  165
  166
  167
  168
  169
  170
// RUN: %clang_cc1 -std=c++1z -verify -pedantic-errors %s

// Check that we deal with cases where the instantiation of a class template
// recursively requires the instantiation of the same template.
namespace test1 {
  template<typename T> struct A {
    struct B { // expected-note {{not complete until the closing '}'}}
      B b; // expected-error {{has incomplete type 'test1::A<int>::B'}}
    };
    B b; // expected-note {{in instantiation of}}
  };
  A<int> a; // expected-note {{in instantiation of}}
}

namespace test2 {
  template<typename T> struct A {
    struct B {
      struct C {};
      char c[1 + C()]; // expected-error {{invalid operands to binary expression}}
      friend constexpr int operator+(int, C) { return 4; }
    };
    B b; // expected-note {{in instantiation of}}
  };
  A<int> a; // expected-note {{in instantiation of}}
}

namespace test3 {
  // PR12317
  template<typename T> struct A {
    struct B {
      enum { Val = 1 };
      char c[1 + Val]; // ok
    };
    B b;
  };
  A<int> a;
}

namespace test4 {
  template<typename T> struct M { typedef int type; };
  template<typename T> struct A {
    struct B { // expected-note {{not complete until the closing '}'}}
      int k[typename A<typename M<T>::type>::B().k[0] + 1]; // expected-error {{incomplete type}}
    };
    B b; // expected-note {{in instantiation of}}
  };
  A<int> a; // expected-note {{in instantiation of}}
}

// PR12298: Recursive constexpr function template instantiation leads to
// stack overflow.
namespace test5 {
  template<typename T> struct A {
    constexpr T f(T k) { return g(k); }
    constexpr T g(T k) {
      return k ? f(k-1)+1 : 0;
    }
  };
  constexpr int x = A<int>().f(5); // ok
}

namespace test6 {
  template<typename T> constexpr T f(T);
  template<typename T> constexpr T g(T t) {
    typedef int arr[f(T())]; // expected-error {{variable length array}}
    return t;
  }
  template<typename T> constexpr T f(T t) {
    typedef int arr[g(T())]; // expected-error {{zero size array}} expected-note {{instantiation of}}
    return t;
  }
  int n = f(0); // expected-note 2{{instantiation of}}
}

namespace test7 {
  template<typename T> constexpr T g(T t) {
    return t;
  }
  template<typename T> constexpr T f(T t) {
    typedef int arr[g(T() + 1)];
    return t;
  }
  int n = f(0);
}

namespace test8 {
  template<typename T> struct A {
    int n = A{}.n; // expected-error {{default member initializer for 'n' uses itself}} expected-note {{instantiation of default member init}}
  };
  A<int> ai = {}; // expected-note {{instantiation of default member init}}
}

namespace test9 {
  template<typename T> struct A { enum class B; };
  // FIXME: It'd be nice to give the "it has not yet been instantiated" diagnostic here.
  template<typename T> enum class A<T>::B { k = A<T>::B::k2, k2 = k }; // expected-error {{no member named 'k2'}}
  auto k = A<int>::B::k; // expected-note {{in instantiation of}}
}

namespace test10 {
  template<typename T> struct A {
    void f() noexcept(noexcept(f())); // expected-error {{exception specification of 'f' uses itself}} expected-note {{instantiation of}}
  };
  bool b = noexcept(A<int>().f()); // expected-note {{instantiation of}}
}

namespace test11 {
  template<typename T> const int var = var<T>;
  int k = var<int>;

  template<typename T> struct X {
    static const int k = X<T>::k;
  };
  template<typename T> const int X<T>::k;
  int q = X<int>::k;

  template<typename T> struct Y {
    static const int k;
  };
  template<typename T> const int Y<T>::k = Y<T>::k;
  int r = Y<int>::k;
}

namespace test12 {
  template<typename T> int f(T t, int = f(T())) {} // expected-error {{recursive evaluation of default argument}} expected-note {{instantiation of}}
  struct X {};
  int q = f(X()); // expected-note {{instantiation of}}
}

namespace test13 {
  struct A {
    // Cycle via type of non-type template parameter.
    template<typename T, typename T::template W<T>::type U = 0> struct W { using type = int; };
    // Cycle via default template argument.
    template<typename T, typename U = typename T::template X<T>> struct X {};
    template<typename T, int U = T::template Y<T>::value> struct Y { static const int value = 0; };
    template<typename T, template<typename> typename U = T::template Z<T>::template nested> struct Z { template<typename> struct nested; };
  };
  template<typename T> struct Wrap {
    template<typename U> struct W : A::W<T> {};
    template<typename U> struct X : A::X<T> {};
    template<typename U> struct Y : A::Y<T> {};
    template<typename U> struct Z : A::Z<T> {};
  };
  struct B {
    template<typename U> struct W { using type = int; };
    template<typename U> struct X {};
    template<typename U> struct Y { static const int value = 0; };
    template<typename U> struct Z { template<typename> struct nested; };
  };

  A::W<B> awb;
  A::X<B> axb;
  A::Y<B> ayb;
  A::Z<B> azb;

  A::W<Wrap<Wrap<B>>> awwwb;
  A::X<Wrap<Wrap<B>>> axwwb;
  A::Y<Wrap<Wrap<B>>> aywwb;
  A::Z<Wrap<Wrap<B>>> azwwb;

  // FIXME: These tests cause us to use too much stack and crash on a self-hosted debug build.
  // FIXME: Check for recursion here and give a better diagnostic.
#if 0
  A::W<A> awa;
  A::X<A> axa;
  A::Y<A> aya;
  A::Z<A> aza;
#endif
}