clang/test/CXX/expr/expr.prim/expr.prim.lambda/p5-generic-lambda-1y.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++1y -DCXX1Y
   2
   3 namespace test_factorial {
   4
   5 auto Fact = [](auto Self, unsigned n) -> unsigned {
   6     return !n ? 1 : Self(Self, n - 1) * n;
   7 };
   8
   9 auto six = Fact(Fact, 3);
  10
  11 }
  12
  13 namespace overload_generic_lambda {
  14   template <class F1, class F2> struct overload : F1, F2 {
  15     using F1::operator();
  16     using F2::operator();
  17     overload(F1 f1, F2 f2) : F1(f1), F2(f2) { }
  18   };
  19
  20   auto NumParams = [](auto Self, auto h, auto ... rest) -> unsigned {
  21     return 1 + Self(Self, rest...);
  22   };
  23   auto Base = [](auto Self, auto h) -> unsigned {
  24       return 1;
  25   };
  26   overload<decltype(Base), decltype(NumParams)> O(Base, NumParams);
  27   int num_params =  O(O, 5, 3, "abc", 3.14, 'a');
  28 }
  29
  30
  31 namespace overload_generic_lambda_return_type_deduction {
  32   template <class F1, class F2> struct overload : F1, F2 {
  33     using F1::operator();
  34     using F2::operator();
  35     overload(F1 f1, F2 f2) : F1(f1), F2(f2) { }
  36   };
  37
  38   auto NumParams = [](auto Self, auto h, auto ... rest) {
  39     return 1 + Self(Self, rest...);
  40   };
  41   auto Base = [](auto Self, auto h) {
  42       return 1;
  43   };
  44   overload<decltype(Base), decltype(NumParams)> O(Base, NumParams);
  45   int num_params =  O(O, 5, 3, "abc", 3.14, 'a');
  46 }
  47
  48 namespace test_standard_p5 {
  49 // FIXME: This test should eventually compile without an explicit trailing return type
  50 auto glambda = [](auto a, auto&& b) ->bool { return a < b; };
  51 bool b = glambda(3, 3.14); // OK
  52
  53 }
  54 namespace test_deduction_failure {
  55  int test() {
  56    auto g = [](auto *a) { //expected-note{{candidate template ignored}}
  57     return a;
  58    };
  59    struct X { };
  60    X *x;
  61    g(x);
  62    g(3); //expected-error{{no matching function}}
  63    return 0;
  64  }
  65
  66 }
  67
  68 namespace test_instantiation_or_sfinae_failure {
  69 int test2() {
  70   {
  71     auto L = [](auto *a) {
  72                 return (*a)(a); }; //expected-error{{called object type 'double' is not a function}}
  73     double d;
  74     L(&d); //expected-note{{in instantiation of}}
  75     auto M = [](auto b) { return b; };
  76     L(&M); // ok
  77   }
  78   {
  79     auto L = [](auto *a) ->decltype (a->foo()) { //expected-note2{{candidate template ignored:}}
  80                 return (*a)(a); };
  81     double d;
  82     L(&d); //expected-error{{no matching function for call}}
  83     auto M = [](auto b) { return b; };
  84     L(&M); //expected-error{{no matching function for call}}
  85
  86   }
  87   return 0;
  88 }
  89
  90
  91 }
  92
  93 namespace test_misc {
  94 auto GL = [](auto a, decltype(a) b) //expected-note{{candidate function}}
  95                 -> int { return a + b; };
  96
  97 void test() {
  98    struct X { };
  99    GL(3, X{}); //expected-error{{no matching function}}
 100 }
 101
 102 void test2() {
 103   auto l = [](auto *a) -> int {
 104               (*a)(a); return 0; }; //expected-error{{called object type 'double' is not a function}}
 105   l(&l);
 106   double d;
 107   l(&d); //expected-note{{in instantiation of}}
 108 }
 109
 110 }
 111
 112 namespace nested_lambdas {
 113   int test() {
 114     auto L = [](auto a) {
 115                  return [=](auto b) {
 116                            return a + b;
 117                         };
 118               };
 119   }
 120   auto get_lambda() {
 121     return [](auto a) {
 122       return a;
 123     };
 124   };
 125
 126   int test2() {
 127     auto L = get_lambda();
 128     L(3);
 129   }
 130 }
 131