128 lines
3.6 KiB
C++
128 lines
3.6 KiB
C++
// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11
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// Implicitly-defined default constructors are constexpr if the implicit
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// definition would be.
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struct NonConstexpr1 { // expected-note {{here}}
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int a;
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};
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struct NonConstexpr2 { // expected-note {{here}}
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NonConstexpr1 nl;
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};
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struct NonConstexpr2a : NonConstexpr1 { };
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constexpr NonConstexpr1 nc1 = NonConstexpr1(); // ok, does not call constructor
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constexpr NonConstexpr2 nc2 = NonConstexpr2(); // ok, does not call constructor
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constexpr NonConstexpr2a nc2a = NonConstexpr2a(); // ok, does not call constructor
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constexpr int nc2_a = NonConstexpr2().nl.a; // ok
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constexpr int nc2a_a = NonConstexpr2a().a; // ok
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struct Helper {
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friend constexpr NonConstexpr1::NonConstexpr1(); // expected-error {{follows non-constexpr declaration}}
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friend constexpr NonConstexpr2::NonConstexpr2(); // expected-error {{follows non-constexpr declaration}}
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};
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struct Constexpr1 {};
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constexpr Constexpr1 c1 = Constexpr1(); // ok
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struct NonConstexpr3 : virtual Constexpr1 {}; // expected-note {{struct with virtual base}} expected-note {{declared here}}
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constexpr NonConstexpr3 nc3 = NonConstexpr3(); // expected-error {{non-literal type 'const NonConstexpr3'}}
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struct Constexpr2 {
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int a = 0;
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};
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constexpr Constexpr2 c2 = Constexpr2(); // ok
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int n;
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struct Member {
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Member() : a(n) {}
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constexpr Member(int&a) : a(a) {}
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int &a;
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};
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struct NonConstexpr4 { // expected-note {{here}}
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Member m;
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};
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constexpr NonConstexpr4 nc4 = NonConstexpr4(); // expected-error {{constant expression}} expected-note {{non-constexpr constructor 'NonConstexpr4'}}
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struct Constexpr3 {
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constexpr Constexpr3() : m(n) {}
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Member m;
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};
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constexpr Constexpr3 c3 = Constexpr3(); // ok
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struct Constexpr4 {
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Constexpr3 m;
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};
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constexpr Constexpr4 c4 = Constexpr4(); // ok
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// This rule breaks some legal C++98 programs!
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struct A {}; // expected-note {{here}}
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struct B {
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friend A::A(); // expected-error {{non-constexpr declaration of 'A' follows constexpr declaration}}
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};
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namespace UnionCtors {
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union A { // expected-note {{here}}
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int a;
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int b;
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};
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union B {
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int a;
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int b = 5;
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};
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union C {
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int a = 5;
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int b;
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};
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struct D {
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union {
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int a = 5;
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int b;
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};
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union {
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int c;
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int d = 5;
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};
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};
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struct E { // expected-note {{here}}
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union {
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int a;
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int b;
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};
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};
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struct Test {
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friend constexpr A::A() noexcept; // expected-error {{follows non-constexpr declaration}}
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friend constexpr B::B() noexcept;
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friend constexpr C::C() noexcept;
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friend constexpr D::D() noexcept;
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friend constexpr E::E() noexcept; // expected-error {{follows non-constexpr declaration}}
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};
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}
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namespace PR48763 {
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// FIXME: We implement a speculative wording fix here: if a class inherits a
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// default constructor and doesn't declare one itself, we declare an default
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// constructor implicitly. This allows us to meanignfully reason about
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// whether that default constructor is constexpr, trivial, and so on.
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struct A { constexpr A() {} };
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struct B : A {
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using A::A;
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constexpr B(int) {}
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};
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struct C { B b; };
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constexpr C c;
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struct D { int n; };
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struct E : D { using D::D; E(int); };
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static_assert(E().n == 0, "");
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static_assert(E{}.n == 0, "");
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struct F { E e; };
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static_assert(F().e.n == 0, "");
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static_assert(F{}.e.n == 0, "");
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union U { E e; };
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U u; // OK, trivial default constructor
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struct G { G(); };
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struct H : D { using D::D; H(int); G g; };
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union V { H h; }; // expected-note {{field 'h' has a non-trivial default constructor}}
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V v; // expected-error {{deleted}}
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}
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