clang/test/CXX/expr/expr.prim/expr.prim.lambda/templates.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -std=c++11 -Winvalid-noreturn %s -verify
   2
   3 template<typename T>
   4 void test_attributes() {
   5   // FIXME: GCC accepts [[gnu::noreturn]] here.
   6   auto nrl = []() [[gnu::noreturn]] {}; // expected-warning{{attribute 'noreturn' ignored}}
   7 }
   8
   9 template void test_attributes<int>();
  10
  11 template<typename T>
  12 void call_with_zero() {
  13   [](T *ptr) -> T& { return *ptr; }(0);
  14 }
  15
  16 template void call_with_zero<int>();
  17
  18 template<typename T>
  19 T captures(T x, T y) {
  20   auto lambda = [=, &y] () -> T {
  21     T i = x;
  22     return i + y;
  23   };
  24
  25   return lambda();
  26 }
  27
  28 struct X {
  29   X(const X&);
  30 };
  31
  32 X operator+(X, X);
  33 X operator-(X, X);
  34
  35 template int captures(int, int);
  36 template X captures(X, X);
  37
  38 template<typename T>
  39 int infer_result(T x, T y) {
  40   auto lambda = [=](bool b) { return x + y; };
  41   return lambda(true); // expected-error{{no viable conversion from returned value of type 'X' to function return type 'int'}}
  42 }
  43
  44 template int infer_result(int, int);
  45 template int infer_result(X, X); // expected-note{{in instantiation of function template specialization 'infer_result<X>' requested here}}
  46
  47 // Make sure that lambda's operator() can be used from templates.
  48 template<typename F>
  49 void accept_lambda(F f) {
  50   f(1);
  51 }
  52
  53 template<typename T>
  54 void pass_lambda(T x) {
  55   accept_lambda([&x](T y) { return x + y; });
  56 }
  57
  58 template void pass_lambda(int);
  59
  60 namespace std {
  61   class type_info;
  62 }
  63
  64 namespace p2 {
  65   struct P {
  66     virtual ~P();
  67   };
  68
  69   template<typename T>
  70   struct Boom {
  71     Boom(const Boom&) {
  72       T* x = 1; // expected-error{{cannot initialize a variable of type 'float *' with an rvalue of type 'int'}}
  73     }
  74     void tickle() const;
  75   };
  76
  77   template<typename R, typename T>
  78   void odr_used(R &r, Boom<T> boom) {
  79     const std::type_info &ti
  80       = typeid([=,&r] () -> R& { // expected-error{{lambda expression in an unevaluated operand}}
  81           boom.tickle();
  82           return r;
  83         }());
  84   }
  85
  86   template void odr_used(int&, Boom<int>); // expected-note{{in instantiation of function template specialization}}
  87
  88   template<typename R, typename T>
  89   void odr_used2(R &r, Boom<T> boom) {
  90     const std::type_info &ti
  91       = typeid([=,&r] () -> R& { // expected-note{{in instantiation of member function 'p2::Boom<float>::Boom' requested here}}
  92           boom.tickle();
  93           return r;
  94         }());
  95   }
  96
  97   template void odr_used2(P&, Boom<float>);
  98 }
  99
 100 namespace p5 {
 101   struct NonConstCopy {
 102     NonConstCopy(const NonConstCopy&) = delete;
 103     NonConstCopy(NonConstCopy&);
 104   };
 105
 106   template<typename T>
 107   void double_capture(T &nc) {
 108     [=] () mutable {
 109       [=] () mutable {
 110         T nc2(nc);
 111       }();
 112     }();
 113   }
 114
 115   template void double_capture(NonConstCopy&);
 116 }
 117
 118 namespace NonLocalLambdaInstantiation {
 119   template<typename T>
 120   struct X {
 121     static int value;
 122   };
 123
 124   template<typename T>
 125   int X<T>::value = []{ return T(); }(); // expected-error{{cannot initialize a variable of type 'int' with an rvalue of type 'int *'}}
 126
 127   template int X<int>::value;
 128   template int X<float>::value;
 129   template int X<int*>::value; // expected-note{{in instantiation of static data member }}
 130
 131   template<typename T>
 132   void defaults(int x = []{ return T(); }()) { }; // expected-error{{cannot initialize a parameter of type 'int' with an rvalue of type 'int *'}} \
 133      // expected-note{{passing argument to parameter 'x' here}}
 134
 135   void call_defaults() {
 136     defaults<int>();
 137     defaults<float>();
 138     defaults<int*>(); // expected-note{{in instantiation of default function argument expression for 'defaults<int *>' required here}}
 139   }
 140
 141   template<typename T>
 142   struct X2 { // expected-note{{in instantiation of default member initializer 'NonLocalLambdaInstantiation::X2<int *>::x'}}
 143     int x = []{ return T(); }(); // expected-error{{cannot initialize a member subobject of type 'int' with an rvalue of type 'int *'}}
 144   };
 145
 146   X2<int> x2i;
 147   X2<float> x2f;
 148   X2<int*> x2ip; // expected-note {{in evaluation of exception spec}}
 149 }