clang/test/AST/ByteCode/cxx2a.cpp

// RUN: %clang_cc1 -std=c++2a -fsyntax-only -fcxx-exceptions -verify=ref,both %s
// RUN: %clang_cc1 -std=c++2a -fsyntax-only -fcxx-exceptions -verify=expected,both %s -fexperimental-new-constant-interpreter

template <unsigned N>
struct S {
  S() requires (N==1) = default;
  S() requires (N==2) {} // both-note {{declared here}}
  consteval S() requires (N==3) = default;
};

consteval int aConstevalFunction() { // both-error {{consteval function never produces a constant expression}}
  S<2> s4; // both-note {{non-constexpr constructor 'S' cannot be used in a constant expression}}
  return 0;
}
/// We're NOT calling the above function. The diagnostics should appear anyway.

namespace Covariant {
  struct A {
    virtual constexpr char f() const { return 'Z'; }
    char a = f();
  };

  struct D : A {};
  struct Covariant1 {
    D d;
    virtual const A *f() const;
  };

  struct Covariant3 : Covariant1 {
    constexpr virtual const D *f() const { return &this->d; }
  };

  constexpr Covariant3 cb;
  constexpr const Covariant1 *cb1 = &cb;
  static_assert(cb1->f()->a == 'Z');
}