clang/test/SemaCXX/constexpr-never-constant.cpp

// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify -fcxx-exceptions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++23 -Winvalid-constexpr -verify -fcxx-exceptions %s
// Note: for a diagnostic that defaults to an error, -Wno-foo -Wfoo will
// disable the diagnostic and then re-enable it *as a warning* rather than as
// an error. So we manually enable it as an error again with -Werror to keep
// the diagnostic checks consistent.
// RUN: %clang_cc1 -fsyntax-only -std=c++23 -Wno-invalid-constexpr -Winvalid-constexpr -Werror=invalid-constexpr -verify -fcxx-exceptions %s

// RUN: %clang_cc1 -fsyntax-only -Wno-invalid-constexpr -verify=good -fcxx-exceptions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++23 -verify=good -fcxx-exceptions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++23 -Wno-invalid-constexpr -verify=good -fcxx-exceptions %s
// RUN: %clang_cc1 -fsyntax-only -std=c++23 -Winvalid-constexpr -Wno-invalid-constexpr -verify=good -fcxx-exceptions %s
// RUN: %clang_cc1 -fsyntax-only -Wno-invalid-constexpr -verify=good -fcxx-exceptions %s
// good-no-diagnostics

constexpr void func() { // expected-error {{constexpr function never produces a constant expression}}
  throw 12;             // expected-note {{subexpression not valid in a constant expression}}
}

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Winvalid-constexpr"
constexpr void other_func() {
#pragma clang diagnostic pop

  throw 12;
}

namespace GH149041 {
  // Make sure these don't trigger the diagnostic.
  extern const bool& b;
  constexpr bool fun1() { return b; }
  constexpr bool fun2(const bool& b) { return b; }
}