| // RUN: %clang_cc1 -fsyntax-only -std=c++11 -pedantic -verify -fcxx-exceptions %s -fconstexpr-depth 128 |
| |
| // A conditional-expression is a core constant expression unless it involves one |
| // of the following as a potentially evaluated subexpression [...]: |
| |
| // - this (5.1.1 [expr.prim.general]) [Note: when evaluating a constant |
| // expression, function invocation substitution (7.1.5 [dcl.constexpr]) |
| // replaces each occurrence of this in a constexpr member function with a |
| // pointer to the class object. -end note]; |
| struct This { |
| int this1 : this1; // expected-error {{undeclared}} |
| int this2 : this->this1; // expected-error {{invalid}} |
| void this3() { |
| int n1[this->this1]; // expected-warning {{variable length array}} |
| int n2[this1]; // expected-warning {{variable length array}} |
| (void)n1, (void)n2; |
| } |
| }; |
| |
| // - an invocation of a function other than a constexpr constructor for a |
| // literal class or a constexpr function [ Note: Overload resolution (13.3) |
| // is applied as usual - end note ]; |
| struct NonConstexpr1 { |
| static int f() { return 1; } // expected-note {{here}} |
| int n : f(); // expected-error {{constant expression}} expected-note {{non-constexpr function 'f' cannot be used in a constant expression}} |
| }; |
| struct NonConstexpr2 { |
| constexpr NonConstexpr2(); // expected-note {{here}} |
| int n; |
| }; |
| struct NonConstexpr3 { |
| NonConstexpr3(); |
| int m : NonConstexpr2().n; // expected-error {{constant expression}} expected-note {{undefined constructor 'NonConstexpr2'}} |
| }; |
| struct NonConstexpr4 { |
| NonConstexpr4(); // expected-note {{declared here}} |
| int n; |
| }; |
| struct NonConstexpr5 { |
| int n : NonConstexpr4().n; // expected-error {{constant expression}} expected-note {{non-constexpr constructor 'NonConstexpr4' cannot be used in a constant expression}} |
| }; |
| |
| // - an invocation of an undefined constexpr function or an undefined |
| // constexpr constructor; |
| struct UndefinedConstexpr { |
| constexpr UndefinedConstexpr(); |
| static constexpr int undefinedConstexpr1(); // expected-note {{here}} |
| int undefinedConstexpr2 : undefinedConstexpr1(); // expected-error {{constant expression}} expected-note {{undefined function 'undefinedConstexpr1' cannot be used in a constant expression}} |
| }; |
| |
| // - an invocation of a constexpr function with arguments that, when substituted |
| // by function invocation substitution (7.1.5), do not produce a constant |
| // expression; |
| namespace NonConstExprReturn { |
| static constexpr const int &id_ref(const int &n) { |
| return n; // expected-note {{reference to temporary cannot be returned from a constexpr function}} |
| } |
| struct NonConstExprFunction { |
| int n : id_ref( // expected-error {{constant expression}} expected-note {{in call to 'id_ref(16)'}} |
| 16 // expected-note {{temporary created here}} |
| ); |
| }; |
| constexpr const int *address_of(const int &a) { |
| return &a; // expected-note {{pointer to 'n' cannot be returned from a constexpr function}} |
| } |
| constexpr const int *return_param(int n) { // expected-note {{declared here}} |
| return address_of(n); // expected-note {{in call to 'address_of(n)'}} |
| } |
| struct S { |
| int n : *return_param(0); // expected-error {{constant expression}} expected-note {{in call to 'return_param(0)'}} |
| }; |
| } |
| |
| // - an invocation of a constexpr constructor with arguments that, when |
| // substituted by function invocation substitution (7.1.5), do not produce all |
| // constant expressions for the constructor calls and full-expressions in the |
| // mem-initializers (including conversions); |
| namespace NonConstExprCtor { |
| struct T { |
| constexpr T(const int &r) : |
| r(r) { // expected-note 2{{reference to temporary cannot be used to initialize a member in a constant expression}} |
| } |
| const int &r; |
| }; |
| constexpr int n = 0; |
| constexpr T t1(n); // ok |
| constexpr T t2(0); // expected-error {{must be initialized by a constant expression}} expected-note {{temporary created here}} expected-note {{in call to 'T(0)'}} |
| |
| struct S { |
| int n : T(4).r; // expected-error {{constant expression}} expected-note {{temporary created here}} expected-note {{in call to 'T(4)'}} |
| }; |
| } |
| |
| // - an invocation of a constexpr function or a constexpr constructor that would |
| // exceed the implementation-defined recursion limits (see Annex B); |
| namespace RecursionLimits { |
| constexpr int RecurseForever(int n) { |
| return n + RecurseForever(n+1); // expected-note {{constexpr evaluation exceeded maximum depth of 128 calls}} expected-note 9{{in call to 'RecurseForever(}} expected-note {{skipping 118 calls}} |
| } |
| struct AlsoRecurseForever { |
| constexpr AlsoRecurseForever(int n) : |
| n(AlsoRecurseForever(n+1).n) // expected-note {{constexpr evaluation exceeded maximum depth of 128 calls}} expected-note 9{{in call to 'AlsoRecurseForever(}} expected-note {{skipping 118 calls}} |
| {} |
| int n; |
| }; |
| struct S { |
| int k : RecurseForever(0); // expected-error {{constant expression}} expected-note {{in call to}} |
| int l : AlsoRecurseForever(0).n; // expected-error {{constant expression}} expected-note {{in call to}} |
| }; |
| } |
| |
| // FIXME: |
| // - an operation that would have undefined behavior [Note: including, for |
| // example, signed integer overflow (Clause 5 [expr]), certain pointer |
| // arithmetic (5.7 [expr.add]), division by zero (5.6 [expr.mul]), or certain |
| // shift operations (5.8 [expr.shift]) -end note]; |
| namespace UndefinedBehavior { |
| void f(int n) { |
| switch (n) { |
| case (int)4.4e9: // expected-error {{constant expression}} expected-note {{value 4.4E+9 is outside the range of representable values of type 'int'}} |
| case (int)(unsigned)(long long)4.4e9: // ok |
| case (float)1e300: // expected-error {{constant expression}} expected-note {{value 1.0E+300 is outside the range of representable values of type 'float'}} |
| case (int)((float)1e37 / 1e30): // ok |
| case (int)(__fp16)65536: // expected-error {{constant expression}} expected-note {{value 65536 is outside the range of representable values of type 'half'}} |
| break; |
| } |
| } |
| |
| struct S { |
| int m; |
| }; |
| constexpr S s = { 5 }; // expected-note {{declared here}} |
| constexpr const int *p = &s.m + 1; |
| constexpr const int &f(const int *q) { |
| return q[0]; // expected-note {{dereferenced pointer past the end of subobject of 's' is not a constant expression}} |
| } |
| constexpr int n = (f(p), 0); // expected-error {{constant expression}} expected-note {{in call to 'f(&s.m + 1)'}} |
| struct T { |
| int n : f(p); // expected-error {{not an integer constant expression}} expected-note {{read of dereferenced one-past-the-end pointer}} |
| }; |
| |
| namespace Ptr { |
| struct A {}; |
| struct B : A { int n; }; |
| B a[3][3]; |
| constexpr B *p = a[0] + 4; // expected-error {{constant expression}} expected-note {{element 4 of array of 3 elements}} |
| B b = {}; |
| constexpr A *pa = &b + 1; // expected-error {{constant expression}} expected-note {{base class of pointer past the end}} |
| constexpr B *pb = (B*)((A*)&b + 1); // expected-error {{constant expression}} expected-note {{derived class of pointer past the end}} |
| constexpr const int *pn = &(&b + 1)->n; // expected-error {{constant expression}} expected-note {{field of pointer past the end}} |
| constexpr B *parr = &a[3][0]; // expected-error {{constant expression}} expected-note {{array element of pointer past the end}} |
| |
| constexpr A *na = nullptr; |
| constexpr B *nb = nullptr; |
| constexpr A &ra = *nb; // expected-error {{constant expression}} expected-note {{cannot access base class of null pointer}} |
| constexpr B &rb = (B&)*na; // expected-error {{constant expression}} expected-note {{cannot access derived class of null pointer}} |
| static_assert((A*)nb == 0, ""); |
| static_assert((B*)na == 0, ""); |
| constexpr const int &nf = nb->n; // expected-error {{constant expression}} expected-note {{cannot access field of null pointer}} |
| constexpr const int &np = (*(int(*)[4])nullptr)[2]; // expected-error {{constant expression}} expected-note {{cannot access array element of null pointer}} |
| } |
| } |
| |
| // - a lambda-expression (5.1.2); |
| struct Lambda { |
| // FIXME: clang crashes when trying to parse this! Revisit this check once |
| // lambdas are fully implemented. |
| //int n : []{ return 1; }(); |
| }; |
| |
| // - an lvalue-to-rvalue conversion (4.1) unless it is applied to |
| namespace LValueToRValue { |
| // - a non-volatile glvalue of integral or enumeration type that refers to a |
| // non-volatile const object with a preceding initialization, initialized |
| // with a constant expression [Note: a string literal (2.14.5 [lex.string]) |
| // corresponds to an array of such objects. -end note], or |
| volatile const int vi = 1; // expected-note {{here}} |
| const int ci = 1; |
| volatile const int &vrci = ci; |
| static_assert(vi, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type 'const volatile int'}} |
| static_assert(const_cast<int&>(vi), ""); // expected-error {{constant expression}} expected-note {{read of volatile object 'vi'}} |
| static_assert(vrci, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type}} |
| |
| // - a non-volatile glvalue of literal type that refers to a non-volatile |
| // object defined with constexpr, or that refers to a sub-object of such an |
| // object, or |
| struct S { |
| constexpr S(int=0) : i(1), v(1) {} |
| constexpr S(const S &s) : i(2), v(2) {} |
| int i; |
| volatile int v; |
| }; |
| constexpr S s; |
| constexpr volatile S vs; // expected-note {{here}} |
| constexpr const volatile S &vrs = s; |
| static_assert(s.i, ""); |
| static_assert(s.v, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type}} |
| static_assert(vs.i, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type}} |
| static_assert(const_cast<int&>(vs.i), ""); // expected-error {{constant expression}} expected-note {{read of volatile object 'vs'}} |
| static_assert(vrs.i, ""); // expected-error {{constant expression}} expected-note {{read of volatile-qualified type}} |
| |
| // - a non-volatile glvalue of literal type that refers to a non-volatile |
| // temporary object whose lifetime has not ended, initialized with a |
| // constant expression; |
| constexpr volatile S f() { return S(); } |
| static_assert(f().i, ""); // ok! there's no lvalue-to-rvalue conversion here! |
| static_assert(((volatile const S&&)(S)0).i, ""); // expected-error {{constant expression}} expected-note {{subexpression}} |
| } |
| |
| // FIXME: |
| // |
| // DR1312: The proposed wording for this defect has issues, so we ignore this |
| // bullet and instead prohibit casts from pointers to cv void (see core-20842 |
| // and core-20845). |
| // |
| // - an lvalue-to-rvalue conversion (4.1 [conv.lval]) that is applied to a |
| // glvalue of type cv1 T that refers to an object of type cv2 U, where T and U |
| // are neither the same type nor similar types (4.4 [conv.qual]); |
| |
| // FIXME: |
| // - an lvalue-to-rvalue conversion (4.1) that is applied to a glvalue that |
| // refers to a non-active member of a union or a subobject thereof; |
| |
| // - an id-expression that refers to a variable or data member of reference type |
| // unless the reference has a preceding initialization, initialized with a |
| // constant expression; |
| namespace References { |
| const int a = 2; |
| int &b = *const_cast<int*>(&a); |
| int c = 10; // expected-note 2 {{here}} |
| int &d = c; |
| constexpr int e = 42; |
| int &f = const_cast<int&>(e); |
| extern int &g; |
| constexpr int &h(); // expected-note 2{{here}} |
| int &i = h(); // expected-note {{here}} expected-note {{undefined function 'h' cannot be used in a constant expression}} |
| constexpr int &j() { return b; } |
| int &k = j(); |
| |
| struct S { |
| int A : a; |
| int B : b; |
| int C : c; // expected-error {{constant expression}} expected-note {{read of non-const variable 'c'}} |
| int D : d; // expected-error {{constant expression}} expected-note {{read of non-const variable 'c'}} |
| int D2 : &d - &c + 1; |
| int E : e / 2; |
| int F : f - 11; |
| int G : g; // expected-error {{constant expression}} |
| int H : h(); // expected-error {{constant expression}} expected-note {{undefined function 'h'}} |
| int I : i; // expected-error {{constant expression}} expected-note {{initializer of 'i' is not a constant expression}} |
| int J : j(); |
| int K : k; |
| }; |
| } |
| |
| // - a dynamic_cast (5.2.7); |
| namespace DynamicCast { |
| struct S { int n; }; |
| constexpr S s { 16 }; |
| struct T { |
| int n : dynamic_cast<const S*>(&s)->n; // expected-warning {{constant expression}} expected-note {{dynamic_cast}} |
| }; |
| } |
| |
| // - a reinterpret_cast (5.2.10); |
| namespace ReinterpretCast { |
| struct S { int n; }; |
| constexpr S s { 16 }; |
| struct T { |
| int n : reinterpret_cast<const S*>(&s)->n; // expected-warning {{constant expression}} expected-note {{reinterpret_cast}} |
| }; |
| struct U { |
| int m : (long)(S*)6; // expected-warning {{constant expression}} expected-note {{reinterpret_cast}} |
| }; |
| } |
| |
| // - a pseudo-destructor call (5.2.4); |
| namespace PseudoDtor { |
| int k; |
| typedef int I; |
| struct T { |
| int n : (k.~I(), 0); // expected-error {{constant expression}} expected-note{{subexpression}} |
| }; |
| } |
| |
| // - increment or decrement operations (5.2.6, 5.3.2); |
| namespace IncDec { |
| int k = 2; |
| struct T { |
| int n : ++k; // expected-error {{constant expression}} |
| int m : --k; // expected-error {{constant expression}} |
| }; |
| } |
| |
| // - a typeid expression (5.2.8) whose operand is of a polymorphic class type; |
| namespace std { |
| struct type_info { |
| virtual ~type_info(); |
| const char *name; |
| }; |
| } |
| namespace TypeId { |
| struct S { virtual void f(); }; |
| constexpr S *p = 0; |
| constexpr const std::type_info &ti1 = typeid(*p); // expected-error {{must be initialized by a constant expression}} expected-note {{typeid applied to expression of polymorphic type 'TypeId::S'}} |
| |
| struct T {} t; |
| constexpr const std::type_info &ti2 = typeid(t); |
| } |
| |
| // - a new-expression (5.3.4); |
| // - a delete-expression (5.3.5); |
| namespace NewDelete { |
| int *p = 0; |
| struct T { |
| int n : *new int(4); // expected-error {{constant expression}} expected-note {{subexpression}} |
| int m : (delete p, 2); // expected-error {{constant expression}} expected-note {{subexpression}} |
| }; |
| } |
| |
| // - a relational (5.9) or equality (5.10) operator where the result is |
| // unspecified; |
| namespace UnspecifiedRelations { |
| int a, b; |
| constexpr int *p = &a, *q = &b; |
| // C++11 [expr.rel]p2: If two pointers p and q of the same type point to |
| // different objects that are not members of the same array or to different |
| // functions, or if only one of them is null, the results of p<q, p>q, p<=q, |
| // and p>=q are unspecified. |
| constexpr bool u1 = p < q; // expected-error {{constant expression}} |
| constexpr bool u2 = p > q; // expected-error {{constant expression}} |
| constexpr bool u3 = p <= q; // expected-error {{constant expression}} |
| constexpr bool u4 = p >= q; // expected-error {{constant expression}} |
| constexpr bool u5 = p < 0; // expected-error {{constant expression}} |
| constexpr bool u6 = p <= 0; // expected-error {{constant expression}} |
| constexpr bool u7 = p > 0; // expected-error {{constant expression}} |
| constexpr bool u8 = p >= 0; // expected-error {{constant expression}} |
| constexpr bool u9 = 0 < q; // expected-error {{constant expression}} |
| constexpr bool u10 = 0 <= q; // expected-error {{constant expression}} |
| constexpr bool u11 = 0 > q; // expected-error {{constant expression}} |
| constexpr bool u12 = 0 >= q; // expected-error {{constant expression}} |
| void f(), g(); |
| |
| constexpr void (*pf)() = &f, (*pg)() = &g; |
| constexpr bool u13 = pf < pg; // expected-error {{constant expression}} |
| constexpr bool u14 = pf == pg; |
| |
| // FIXME: |
| // If two pointers point to non-static data members of the same object with |
| // different access control, the result is unspecified. |
| |
| // FIXME: |
| // [expr.rel]p3: Pointers to void can be compared [...] if both pointers |
| // represent the same address or are both the null pointer [...]; otherwise |
| // the result is unspecified. |
| |
| // FIXME: Implement comparisons of pointers to members. |
| // [expr.eq]p2: If either is a pointer to a virtual member function and |
| // neither is null, the result is unspecified. |
| } |
| |
| // - an assignment or a compound assignment (5.17); or |
| namespace Assignment { |
| int k; |
| struct T { |
| int n : (k = 9); // expected-error {{constant expression}} |
| int m : (k *= 2); // expected-error {{constant expression}} |
| }; |
| |
| struct Literal { |
| constexpr Literal(const char *name) : name(name) {} |
| const char *name; |
| }; |
| struct Expr { |
| constexpr Expr(Literal l) : IsLiteral(true), l(l) {} |
| bool IsLiteral; |
| union { |
| Literal l; |
| // ... |
| }; |
| }; |
| struct MulEq { |
| constexpr MulEq(Expr a, Expr b) : LHS(a), RHS(b) {} |
| Expr LHS; |
| Expr RHS; |
| }; |
| constexpr MulEq operator*=(Expr a, Expr b) { return MulEq(a, b); } |
| Literal a("a"); |
| Literal b("b"); |
| MulEq c = a *= b; // ok |
| } |
| |
| // - a throw-expression (15.1) |
| namespace Throw { |
| struct S { |
| int n : (throw "hello", 10); // expected-error {{constant expression}} expected-note {{subexpression}} |
| }; |
| } |
| |
| // PR9999 |
| template<bool v> |
| class bitWidthHolding { |
| public: |
| static const |
| unsigned int width = (v == 0 ? 0 : bitWidthHolding<(v >> 1)>::width + 1); |
| }; |
| |
| static const int width=bitWidthHolding<255>::width; |
| |
| template<bool b> |
| struct always_false { |
| static const bool value = false; |
| }; |
| |
| template<bool b> |
| struct and_or { |
| static const bool and_value = b && and_or<always_false<b>::value>::and_value; |
| static const bool or_value = !b || and_or<always_false<b>::value>::or_value; |
| }; |
| |
| static const bool and_value = and_or<true>::and_value; |
| static const bool or_value = and_or<true>::or_value; |