119 lines · cpp
1// RUN: %clang_cc1 -verify=expected,both -std=c++20 %s -fexperimental-new-constant-interpreter2// RUN: %clang_cc1 -verify=ref,both -std=c++20 %s3 4/// FIXME: Slight difference in diagnostic output here.5 6struct Foo {7 int a;8};9 10constexpr int dead1() {11 12 Foo *F2 = nullptr;13 {14 Foo F{12}; // expected-note {{declared here}}15 F2 = &F;16 } // Ends lifetime of F.17 18 return F2->a; // expected-note {{read of variable whose lifetime has ended}} \19 // ref-note {{read of object outside its lifetime is not allowed in a constant expression}}20}21static_assert(dead1() == 1, ""); // both-error {{not an integral constant expression}} \22 // both-note {{in call to}}23 24 25struct S {26 int &&r; // both-note {{reference member declared here}}27 int t;28 constexpr S() : r(0), t(r) {} // both-error {{reference member 'r' binds to a temporary object whose lifetime would be shorter than the lifetime of the constructed object}} \29 // ref-note {{read of object outside its lifetime is not allowed in a constant expression}} \30 // expected-note {{temporary created here}} \31 // expected-note {{read of temporary whose lifetime has ended}}32};33constexpr int k1 = S().t; // both-error {{must be initialized by a constant expression}} \34 // both-note {{in call to}}35 36 37namespace MoveFnWorks {38 template<typename T> constexpr T &&ref(T &&t) { return (T&&)t; }39 40 struct Buf {};41 42 struct A {43 constexpr A(Buf &buf) : buf(buf) { }44 Buf &buf;45 };46 47 constexpr bool dtor_calls_dtor() {48 struct B {49 A &&d;50 constexpr B(Buf &buf) : d(ref(A(buf))) {}51 };52 53 Buf buf;54 {55 B b(buf);56 }57 58 return true;59 }60 static_assert(dtor_calls_dtor(), "");61}62 63namespace PrimitiveMoveFn {64 /// This used to crash.65 void test() {66 const float y = 100;67 const float &x = y;68 }69}70 71/// FIXME:72/// 1) This doesn't work for parameters73/// 2) We need to do this for all fields in composite scenarios74namespace PseudoDtor {75 typedef int I;76 constexpr bool foo() { // both-error {{never produces a constant expression}}77 {78 int a; // both-note {{destroying object 'a' whose lifetime has already ended}}79 a.~I();80 }81 return true;82 }83 84 int k;85 struct T {86 int n : (k.~I(), 1); // both-error {{constant expression}} \87 // both-note {{visible outside that expression}}88 };89}90 91/// Diagnostic differences92namespace CallScope {93 struct Q {94 int n = 0;95 constexpr int f() const { return 0; }96 };97 constexpr Q *out_of_lifetime(Q q) { return &q; } // both-warning {{address of stack}} \98 // expected-note 2{{declared here}}99 constexpr int k3 = out_of_lifetime({})->n; // both-error {{must be initialized by a constant expression}} \100 // expected-note {{read of variable whose lifetime has ended}} \101 // ref-note {{read of object outside its lifetime}}102 103 constexpr int k4 = out_of_lifetime({})->f(); // both-error {{must be initialized by a constant expression}} \104 // expected-note {{member call on variable whose lifetime has ended}} \105 // ref-note {{member call on object outside its lifetime}}106}107 108namespace ExprDoubleDestroy {109 template <typename T>110 constexpr bool test() {111 T{}.~T(); // both-note {{lifetime has already ended}}112 return true;113 }114 115 struct S { int x; };116 constexpr bool t = test<S>(); // both-error {{must be initialized by a constant expression}} \117 // both-note {{in call to}}118}119