1 // RUN: %clang_cc1 -fsyntax-only -verify %s -Wno-unused-value -std=c++17 2 // expected-no-diagnostics 3 namespace test1 { 4 return_num()5template <int num> int return_num() { return num; } 6 7 template <typename lambda> struct lambda_wrapper { 8 lambda &outer_lambda; lambda_wrappertest1::lambda_wrapper9 lambda_wrapper(lambda& outer_lambda) : outer_lambda(outer_lambda) {} operator +test1::lambda_wrapper10 template <typename T> auto operator+(T t) { outer_lambda(t); return 1; } 11 }; 12 13 template <int... nums, typename lambda> bw(lambda & outer_lambda)14void bw(lambda& outer_lambda) { 15 (lambda_wrapper(outer_lambda) + ... + return_num<nums>()); 16 } 17 check_return_type(lambda inner_lambda)18template <typename lambda> auto check_return_type(lambda inner_lambda) { 19 using inner_lambda_return_type = decltype(inner_lambda(5)); 20 } 21 cs()22void cs() { 23 auto outer_lambda = [](auto param) { 24 auto inner_lambda = [](auto o) -> decltype(param) {}; 25 check_return_type(inner_lambda); 26 }; 27 bw<1,2>(outer_lambda); 28 } 29 30 } // namespace test1 31 32 namespace test2 { 33 34 template <typename lambda> run_lambda_with_zero(lambda l)35auto run_lambda_with_zero(lambda l) { 36 l(0); 37 } 38 template <typename ... Ts, typename lambda> run_lambda_once_per_type(lambda l)39void run_lambda_once_per_type(lambda l) { 40 ((Ts{}, run_lambda_with_zero(l)), ...); 41 } inner_function()42template <typename> void inner_function() { 43 char c; 44 [](auto param) -> decltype(c) { return param; }(0); 45 } run()46void run() { 47 auto x = [](auto) -> void { inner_function<int>(); }; 48 run_lambda_once_per_type<int>(x); 49 } 50 51 } // namespace test2 52