clang/test/Parser/cxx2a-template-lambdas.cpp

   1 // RUN: %clang_cc1 -std=c++23 %s -verify
   2 // RUN: %clang_cc1 -std=c++20 %s -verify
   3
   4 auto L0 = []<> { }; //expected-error {{cannot be empty}}
   5
   6 auto L1 = []<typename T1, typename T2> { };
   7 auto L2 = []<typename T1, typename T2>(T1 arg1, T2 arg2) -> T1 { };
   8 auto L3 = []<typename T>(auto arg) { T t; };
   9 auto L4 = []<int I>() { };
  10
  11 // http://llvm.org/PR49736
  12 auto L5 = []<auto>(){};
  13 auto L6 = []<auto>{};
  14 auto L7 = []<auto>() noexcept {};
  15 auto L8 = []<auto> noexcept {};
  16 #if __cplusplus <= 202002L
  17 // expected-warning@-2 {{lambda without a parameter clause is a C++23 extension}}
  18 #endif
  19 auto L9 = []<auto> requires true {};
  20 auto L10 = []<auto> requires true(){};
  21 auto L11 = []<auto> requires true() noexcept {};
  22 auto L12 = []<auto> requires true noexcept {};
  23 #if __cplusplus <= 202002L
  24 // expected-warning@-2 {{is a C++23 extension}}
  25 #endif
  26 auto L13 = []<auto>() noexcept requires true {};
  27 auto L14 = []<auto> requires true() noexcept requires true {};
  28
  29 auto XL0 = []<auto> noexcept requires true {};               // expected-error {{expected body of lambda expression}}
  30 auto XL1 = []<auto> requires true noexcept requires true {}; // expected-error {{expected body}}
  31 #if __cplusplus <= 202002L
  32 // expected-warning@-3 {{is a C++23 extension}}
  33 // expected-warning@-3 {{is a C++23 extension}}
  34 #endif
  35
  36 namespace GH64962 {
  37 void f() {
  38   [] <typename T>(T i) -> int[] // expected-error {{function cannot return array type 'int[]'}}
  39                                 // extension-warning {{explicit template parameter list for lambdas is a C++20 extension}}
  40     { return 3; } (v); // expected-error {{use of undeclared identifier 'v'}}
  41 }
  42 }