// RUN: %clang_cc1 -fsyntax-only -std=c++17 -Wc++2a-compat-pedantic -verify %s // RUN: %clang_cc1 -fsyntax-only -std=c++2a -pedantic -verify %s struct A { // expected-note 0+{{candidate}} A() = default; // expected-note 0+{{candidate}} int x, y; }; A a1 = {1, 2}; #if __cplusplus <= 201703L // expected-warning@-2 {{aggregate initialization of type 'A' with user-declared constructors is incompatible with C++2a}} #else // expected-error@-4 {{no matching constructor}} #endif A a2 = {}; struct B : A { A a; }; B b1 = {{}, {}}; // ok B b2 = {1, 2, 3, 4}; #if __cplusplus <= 201703L // expected-warning@-2 2{{aggregate initialization of type 'A' with user-declared constructors is incompatible with C++2a}} #else // expected-error@-4 2{{no viable conversion from 'int' to 'A'}} #endif // Essentially any use of a u8 string literal in C++<=17 is broken by C++20. // Just warn on all such string literals. struct string { string(const char*); }; // expected-note 0+{{candidate}} char u8arr[] = u8"hello"; const char *u8ptr = "wo" u8"rld"; string u8str = u8"test" u8"test"; #if __cplusplus <= 201703L // expected-warning@-4 {{type of UTF-8 string literal will change}} expected-note@-4 {{remove 'u8' prefix}} // expected-warning@-4 {{type of UTF-8 string literal will change}} expected-note@-4 {{remove 'u8' prefix}} // expected-warning@-4 {{type of UTF-8 string literal will change}} expected-note@-4 {{remove 'u8' prefix}} #else // expected-error@-8 {{ISO C++20 does not permit initialization of char array with UTF-8 string literal}} // expected-error@-8 {{cannot initialize a variable of type 'const char *' with an lvalue of type 'const char8_t [6]'}} // expected-error@-8 {{no viable conversion from 'const char8_t [9]' to 'string'}} #endif