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Diffstat (limited to 'clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp')
-rw-r--r-- | clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp new file mode 100644 index 0000000..65573c7 --- /dev/null +++ b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p4.cpp @@ -0,0 +1,249 @@ +// RUN: %clang_cc1 -verify -std=c++11 -fcxx-exceptions %s + +namespace N { + typedef char C; +} + +namespace M { + typedef double D; +} + +struct NonLiteral { // expected-note 2{{no constexpr constructors}} + NonLiteral() {} + NonLiteral(int) {} +}; +struct Literal { + constexpr Literal() {} + explicit Literal(int); // expected-note 2 {{here}} + operator int() const { return 0; } +}; + +// In the definition of a constexpr constructor, each of the parameter types +// shall be a literal type. +struct S { + constexpr S(int, N::C) {} + constexpr S(int, NonLiteral, N::C) {} // expected-error {{constexpr constructor's 2nd parameter type 'NonLiteral' is not a literal type}} + constexpr S(int, NonLiteral = 42) {} // expected-error {{constexpr constructor's 2nd parameter type 'NonLiteral' is not a literal type}} + + // In addition, either its function-body shall be = delete or = default + constexpr S() = default; + constexpr S(Literal) = delete; +}; + +// or it shall satisfy the following constraints: + +// - the class shall not have any virtual base classes; +struct T : virtual S { // expected-note {{here}} + constexpr T() {} // expected-error {{constexpr constructor not allowed in struct with virtual base class}} +}; +namespace IndirectVBase { + struct A {}; + struct B : virtual A {}; // expected-note {{here}} + class C : public B { + public: + constexpr C() {} // expected-error {{constexpr constructor not allowed in class with virtual base class}} + }; +} + +// - its function-body shall not be a function-try-block; +struct U { + constexpr U() + try // expected-error {{function try block not allowed in constexpr constructor}} + : u() { + } catch (...) { + throw; + } + int u; +}; + +// - the compound-statememt of its function-body shall contain only +struct V { + constexpr V() { + // - null statements, + ; + + // - static_assert-declarations, + static_assert(true, "the impossible happened!"); + + // - typedef declarations and alias-declarations that do not define classes + // or enumerations, + typedef int I; + typedef struct S T; + using J = int; + using K = int[sizeof(I) + sizeof(J)]; + // Note, the standard requires we reject this. + struct U; + + // - using-declarations, + using N::C; + + // - and using-directives; + using namespace N; + } + + constexpr V(int(&)[1]) { + for (int n = 0; n < 10; ++n) // expected-error {{statement not allowed in constexpr constructor}} + /**/; + } + constexpr V(int(&)[2]) { + constexpr int a = 0; // expected-error {{variables cannot be declared in a constexpr constructor}} + } + constexpr V(int(&)[3]) { + constexpr int ForwardDecl(int); // expected-error {{statement not allowed in constexpr constructor}} + } + constexpr V(int(&)[4]) { + typedef struct { } S1; // expected-error {{types cannot be defined in a constexpr constructor}} + } + constexpr V(int(&)[5]) { + using S2 = struct { }; // expected-error {{types cannot be defined in a constexpr constructor}} + } + constexpr V(int(&)[6]) { + struct S3 { }; // expected-error {{types cannot be defined in a constexpr constructor}} + } + constexpr V(int(&)[7]) { + return; // expected-error {{statement not allowed in constexpr constructor}} + } +}; + +// - every non-static data member and base class sub-object shall be initialized +struct W { + int n; // expected-note {{member not initialized by constructor}} + constexpr W() {} // expected-error {{constexpr constructor must initialize all members}} +}; +struct AnonMembers { + int a; // expected-note {{member not initialized by constructor}} + union { // expected-note 2{{member not initialized by constructor}} + char b; + struct { + double c; + long d; // expected-note {{member not initialized by constructor}} + }; + union { + char e; + void *f; + }; + }; + struct { // expected-note {{member not initialized by constructor}} + long long g; + struct { + int h; // expected-note {{member not initialized by constructor}} + double i; // expected-note {{member not initialized by constructor}} + }; + union { // expected-note 2{{member not initialized by constructor}} + char *j; + AnonMembers *k; + }; + }; + + constexpr AnonMembers(int(&)[1]) : a(), b(), g(), h(), i(), j() {} // ok + // missing d, i, j/k union + constexpr AnonMembers(int(&)[2]) : a(), c(), g(), h() {} // expected-error {{constexpr constructor must initialize all members}} + constexpr AnonMembers(int(&)[3]) : a(), e(), g(), h(), i(), k() {} // ok + // missing h, j/k union + constexpr AnonMembers(int(&)[4]) : a(), c(), d(), g(), i() {} // expected-error {{constexpr constructor must initialize all members}} + // missing b/c/d/e/f union + constexpr AnonMembers(int(&)[5]) : a(), g(), h(), i(), k() {} // expected-error {{constexpr constructor must initialize all members}} + // missing a, b/c/d/e/f union, g/h/i/j/k struct + constexpr AnonMembers(int(&)[6]) {} // expected-error {{constexpr constructor must initialize all members}} +}; + +union Empty { + constexpr Empty() {} // ok +} constexpr empty1; + +struct EmptyVariant { + union {}; + struct {}; + constexpr EmptyVariant() {} // ok +} constexpr empty2; + +template<typename T> using Int = int; +template<typename T> +struct TemplateInit { + T a; + int b; // desired-note {{not initialized}} + Int<T> c; // desired-note {{not initialized}} + struct { + T d; + int e; // desired-note {{not initialized}} + Int<T> f; // desired-note {{not initialized}} + }; + struct { + Literal l; + Literal m; + Literal n[3]; + }; + union { // desired-note {{not initialized}} + T g; + T h; + }; + // FIXME: This is ill-formed (no diagnostic required). We should diagnose it. + constexpr TemplateInit() {} // desired-error {{must initialize all members}} +}; +template<typename T> struct TemplateInit2 { + Literal l; + constexpr TemplateInit2() {} // ok +}; + +template<typename T> struct weak_ptr { + constexpr weak_ptr() : p(0) {} + T *p; +}; +template<typename T> struct enable_shared_from_this { + weak_ptr<T> weak_this; + constexpr enable_shared_from_this() {} // ok +}; +constexpr int f(enable_shared_from_this<int>); + +// - every constructor involved in initializing non-static data members and base +// class sub-objects shall be a constexpr constructor. +struct ConstexprBaseMemberCtors : Literal { + Literal l; + + constexpr ConstexprBaseMemberCtors() : Literal(), l() {} // ok + constexpr ConstexprBaseMemberCtors(char) : // expected-error {{constexpr constructor never produces a constant expression}} + Literal(0), // expected-note {{non-constexpr constructor}} + l() {} + constexpr ConstexprBaseMemberCtors(double) : Literal(), // expected-error {{constexpr constructor never produces a constant expression}} + l(0) // expected-note {{non-constexpr constructor}} + {} +}; + +// - every assignment-expression that is an initializer-caluse appearing +// directly or indirectly within a brace-or-equal-initializer for a non-static +// data member that is not named by a mem-initializer-id shall be a constant +// expression; and +// +// Note, we deliberately do not implement this bullet, so that we can allow the +// following example. (See N3308). +struct X { + int a = 0; + int b = 2 * a + 1; // ok, not a constant expression. + + constexpr X() {} + constexpr X(int c) : a(c) {} // ok, b initialized by 2 * c + 1 +}; + +// - every implicit conversion used in converting a constructor argument to the +// corresponding parameter type and converting a full-expression to the +// corresponding member type shall be one of those allowed in a constant +// expression. +// +// We implement the proposed resolution of DR1364 and ignore this bullet. +// However, we implement the intent of this wording as part of the p5 check that +// the function must be able to produce a constant expression. +int kGlobal; // expected-note {{here}} +struct Z { + constexpr Z(int a) : n(a) {} + constexpr Z() : n(kGlobal) {} // expected-error {{constexpr constructor never produces a constant expression}} expected-note {{read of non-const}} + int n; +}; + + +namespace StdExample { + struct Length { + explicit constexpr Length(int i = 0) : val(i) { } + private: + int val; + }; +} |