p2-0x.cpp revision c1c5f27c64dfc3332d53ad30e44d626e4f9afac3
1c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// RUN: %clang_cc1 -fsyntax-only -std=c++11 -pedantic -verify -fcxx-exceptions %s 2c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 3c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// A conditional-expression is a core constant expression unless it involves one 4c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// of the following as a potentially evaluated subexpression [...]: 5c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 6c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - this (5.1.1 [expr.prim.general]) [Note: when evaluating a constant 7c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// expression, function invocation substitution (7.1.5 [dcl.constexpr]) 8c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// replaces each occurrence of this in a constexpr member function with a 9c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// pointer to the class object. -end note]; 10c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct This { 11c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int this1 : this1; // expected-error {{undeclared}} 12c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int this2 : this->this1; // expected-error {{invalid}} 13c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith void this3() { 14c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n1[this->this1]; // expected-warning {{variable length array}} 15c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n2[this1]; // expected-warning {{variable length array}} 16c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith (void)n1, (void)n2; 17c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 18c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 19c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 20c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an invocation of a function other than a constexpr constructor for a 21c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// literal class or a constexpr function [ Note: Overload resolution (13.3) 22c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// is applied as usual - end note ]; 23c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct NonConstexpr1 { 24c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith static int f() { return 1; } // expected-note {{here}} 25c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : f(); // expected-error {{constant expression}} expected-note {{non-constexpr function 'f' cannot be used in a constant expression}} 26c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 27c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct NonConstexpr2 { 28c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr NonConstexpr2(); // expected-note {{here}} 29c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n; 30c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 31c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct NonConstexpr3 { 32c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith NonConstexpr3(); 33c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int m : NonConstexpr2().n; // expected-error {{constant expression}} expected-note {{undefined constructor 'NonConstexpr2'}} 34c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 35c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct NonConstexpr4 { 36c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith NonConstexpr4(); 37c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n; 38c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 39c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct NonConstexpr5 { 40c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : NonConstexpr4().n; // expected-error {{constant expression}} expected-note {{non-literal type 'NonConstexpr4' cannot be used in a constant expression}} 41c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 42c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 43c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an invocation of an undefined constexpr function or an undefined 44c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// constexpr constructor; 45c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct UndefinedConstexpr { 46c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr UndefinedConstexpr(); 47c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith static constexpr int undefinedConstexpr1(); // expected-note {{here}} 48c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int undefinedConstexpr2 : undefinedConstexpr1(); // expected-error {{constant expression}} expected-note {{undefined function 'undefinedConstexpr1' cannot be used in a constant expression}} 49c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 50c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 51c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an invocation of a constexpr function with arguments that, when substituted 52c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// by function invocation substitution (7.1.5), do not produce a constant 53c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// expression; 54c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace NonConstExprReturn { 55c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith static constexpr const int &id_ref(const int &n) { 56c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith return n; // expected-note {{reference to temporary cannot be returned from a constexpr function}} 57c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 58c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct NonConstExprFunction { 59c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : id_ref( // expected-error {{constant expression}} 60c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 16 // expected-note {{temporary created here}} 61c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith ); 62c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 63c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr const int *address_of(const int &a) { 64c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith return &a; // expected-note {{pointer to 'n' cannot be returned from a constexpr function}} 65c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 66c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr const int *return_param(int n) { // expected-note {{declared here}} 67c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith return address_of(n); 68c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 69c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { 70c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : *return_param(0); // expected-error {{constant expression}} 71c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 72c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 73c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 74c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an invocation of a constexpr constructor with arguments that, when 75c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// substituted by function invocation substitution (7.1.5), do not produce all 76c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// constant expressions for the constructor calls and full-expressions in the 77c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// mem-initializers (including conversions); 78c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace NonConstExprCtor { 79c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 80c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr T(const int &r) : 81c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith r(r) { // expected-note {{reference to temporary cannot be used to initialize a member in a constant expression}} 82c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 83c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith const int &r; 84c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 85c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr int n = 0; 86c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr T t1(n); // ok 87c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr T t2(0); // expected-error {{must be initialized by a constant expression}} 88c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 89c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { 90c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : T(4).r; // expected-error {{constant expression}} expected-note {{temporary created here}} 91c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 92c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 93c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 94c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an invocation of a constexpr function or a constexpr constructor that would 95c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// exceed the implementation-defined recursion limits (see Annex B); 96c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace RecursionLimits { 97c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr int RecurseForever(int n) { 98c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith return n + RecurseForever(n+1); // expected-note {{constexpr evaluation exceeded maximum depth of 512 calls}} 99c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 100c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct AlsoRecurseForever { 101c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr AlsoRecurseForever(int n) : 102c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith n(AlsoRecurseForever(n+1).n) // expected-note {{constexpr evaluation exceeded maximum depth of 512 calls}} 103c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith {} 104c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n; 105c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 106c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { 107c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int k : RecurseForever(0); // expected-error {{constant expression}} 108c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int l : AlsoRecurseForever(0).n; // expected-error {{constant expression}} 109c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 110c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 111c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 112c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// FIXME: 113c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an operation that would have undefined behavior [Note: including, for 114c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// example, signed integer overflow (Clause 5 [expr]), certain pointer 115c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// arithmetic (5.7 [expr.add]), division by zero (5.6 [expr.mul]), or certain 116c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// shift operations (5.8 [expr.shift]) -end note]; 117c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace UndefinedBehavior { 118c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith void f(int n) { 119c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith switch (n) { 120c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith case (int)4.4e9: // expected-error {{constant expression}} expected-note {{value 4.4E+9 is outside the range of representable values of type 'int'}} 121c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith case (int)(unsigned)(long long)4.4e9: // ok 122c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith case (float)1e300: // expected-error {{constant expression}} expected-note {{value 1.0E+300 is outside the range of representable values of type 'float'}} 123c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith case (int)((float)1e37 / 1e30): // ok 124c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith case (int)(__fp16)65536: // expected-error {{constant expression}} expected-note {{value 65536 is outside the range of representable values of type 'half'}} 125c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith break; 126c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 127c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 128c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 129c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { 130c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int m; 131c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 132c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr S s = { 5 }; // expected-note {{declared here}} 133c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr const int *p = &s.m + 1; 134c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr const int &f(const int *q) { 135c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith return q[0]; // expected-note {{dereferenced pointer past the end of subobject of 's' is not a constant expression}} 136c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith } 137c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 138c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : f(p); // expected-error {{not an integer constant expression}} 139c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 140c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 141c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 142c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a lambda-expression (5.1.2); 143c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithstruct Lambda { 144c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // FIXME: clang crashes when trying to parse this! Revisit this check once 145c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // lambdas are fully implemented. 146c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith //int n : []{ return 1; }(); 147c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith}; 148c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 149c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// FIXME: 150c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an lvalue-to-rvalue conversion (4.1) unless it is applied to 151c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// 152c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a non-volatile glvalue of integral or enumeration type that refers to a 153c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// non-volatile const object with a preceding initialization, initialized with 154c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// a constant expression [Note: a string literal (2.14.5 [lex.string]) 155c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// corresponds to an array of such objects. -end note], or 156c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// 157c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a non-volatile glvalue of literal type that refers to a non-volatile 158c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// object defined with constexpr, or that refers to a sub-object of such an 159c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// object, or 160c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// 161c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a non-volatile glvalue of literal type that refers to a non-volatile 162c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// temporary object whose lifetime has not ended, initialized with a constant 163c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// expression; 164c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 165c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// FIXME: 166c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// 167c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// DR1312: The proposed wording for this defect has issues, so we instead 168c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// prohibit casts from pointers to cv void (see core-20842 and core-20845). 169c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// 170c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an lvalue-to-rvalue conversion (4.1 [conv.lval]) that is applied to a 171c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// glvalue of type cv1 T that refers to an object of type cv2 U, where T and U 172c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// are neither the same type nor similar types (4.4 [conv.qual]); 173c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 174c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// FIXME: 175c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an lvalue-to-rvalue conversion (4.1) that is applied to a glvalue that 176c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// refers to a non-active member of a union or a subobject thereof; 177c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 178c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// FIXME: 179c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an id-expression that refers to a variable or data member of reference type 180c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// unless the reference has a preceding initialization, initialized with a 181c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// constant expression; 182c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace References { 183c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith const int a = 2; 184c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int &b = *const_cast<int*>(&a); 185c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int c = 10; 186c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int &d = c; 187c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr int e = 42; 188c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int &f = const_cast<int&>(e); 189c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith extern int &g; 190c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr int &h(); // expected-note {{here}} 191c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int &i = h(); 192c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr int &j() { return b; } 193c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int &k = j(); 194c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 195c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { 196c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int A : a; 197c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int B : b; 198c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int C : c; // expected-error {{constant expression}} 199c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int D : d; // expected-error {{constant expression}} 200c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int D2 : &d - &c + 1; 201c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int E : e / 2; 202c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int F : f - 11; 203c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int G : g; // expected-error {{constant expression}} 204c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int H : h(); // expected-error {{constant expression}} expected-note {{undefined function 'h'}} 205c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int I : i; // expected-error {{constant expression}} 206c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int J : j(); 207c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int K : k; 208c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 209c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 210c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 211c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a dynamic_cast (5.2.7); 212c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace DynamicCast { 213c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { int n; }; 214c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr S s { 16 }; 215c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 216c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : dynamic_cast<const S*>(&s)->n; // expected-warning {{constant expression}} expected-note {{dynamic_cast}} 217c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 218c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 219c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 220c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a reinterpret_cast (5.2.10); 221c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace ReinterpretCast { 222c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { int n; }; 223c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr S s { 16 }; 224c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 225c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : reinterpret_cast<const S*>(&s)->n; // expected-warning {{constant expression}} expected-note {{reinterpret_cast}} 226c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 227c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct U { 228c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int m : (long)(S*)6; // expected-warning {{constant expression}} expected-note {{reinterpret_cast}} 229c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 230c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 231c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 232c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a pseudo-destructor call (5.2.4); 233c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace PseudoDtor { 234c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int k; 235c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith typedef int I; 236c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 237c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : (k.~I(), 0); // expected-error {{constant expression}} expected-note{{subexpression}} 238c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 239c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 240c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 241c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - increment or decrement operations (5.2.6, 5.3.2); 242c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace IncDec { 243c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int k = 2; 244c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 245c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : ++k; // expected-error {{constant expression}} 246c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int m : --k; // expected-error {{constant expression}} 247c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 248c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 249c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 250c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a typeid expression (5.2.8) whose operand is of a polymorphic class type; 251c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace std { 252c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct type_info { 253c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith virtual ~type_info(); 254c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith const char *name; 255c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 256c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 257c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace TypeId { 258c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { virtual void f(); }; 259c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr S *p = 0; 260c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr const std::type_info &ti1 = typeid(*p); // expected-error {{must be initialized by a constant expression}} 261c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 262c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // FIXME: Implement typeid evaluation. 263c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T {} t; 264c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr const std::type_info &ti2 = typeid(t); // unexpected-error {{must be initialized by a constant expression}} 265c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 266c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 267c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a new-expression (5.3.4); 268c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a delete-expression (5.3.5); 269c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace NewDelete { 270c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int *p = 0; 271c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 272c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : *new int(4); // expected-error {{constant expression}} expected-note {{subexpression}} 273c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int m : (delete p, 2); // expected-error {{constant expression}} expected-note {{subexpression}} 274c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 275c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 276c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 277c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a relational (5.9) or equality (5.10) operator where the result is 278c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// unspecified; 279c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace UnspecifiedRelations { 280c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int a, b; 281c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr int *p = &a, *q = &b; 282c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // C++11 [expr.rel]p2: If two pointers p and q of the same type point to 283c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // different objects that are not members of the same array or to different 284c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // functions, or if only one of them is null, the results of p<q, p>q, p<=q, 285c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // and p>=q are unspecified. 286c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u1 = p < q; // expected-error {{constant expression}} 287c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u2 = p > q; // expected-error {{constant expression}} 288c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u3 = p <= q; // expected-error {{constant expression}} 289c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u4 = p >= q; // expected-error {{constant expression}} 290c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u5 = p < 0; // expected-error {{constant expression}} 291c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u6 = p <= 0; // expected-error {{constant expression}} 292c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u7 = p > 0; // expected-error {{constant expression}} 293c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u8 = p >= 0; // expected-error {{constant expression}} 294c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u9 = 0 < q; // expected-error {{constant expression}} 295c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u10 = 0 <= q; // expected-error {{constant expression}} 296c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u11 = 0 > q; // expected-error {{constant expression}} 297c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u12 = 0 >= q; // expected-error {{constant expression}} 298c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith void f(), g(); 299c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 300c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr void (*pf)() = &f, (*pg)() = &g; 301c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u13 = pf < pg; // expected-error {{constant expression}} 302c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr bool u14 = pf == pg; 303c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 304c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // FIXME: 305c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // If two pointers point to non-static data members of the same object with 306c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // different access control, the result is unspecified. 307c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 308c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // FIXME: 309c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // [expr.rel]p3: Pointers to void can be compared [...] if both pointers 310c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // represent the same address or are both the null pointer [...]; otherwise 311c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // the result is unspecified. 312c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 313c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // FIXME: Implement comparisons of pointers to members. 314c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // [expr.eq]p2: If either is a pointer to a virtual member function and 315c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // neither is null, the result is unspecified. 316c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 317c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 318c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - an assignment or a compound assignment (5.17); or 319c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace Assignment { 320c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int k; 321c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct T { 322c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : (k = 9); // expected-error {{constant expression}} 323c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int m : (k *= 2); // expected-error {{constant expression}} 324c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 325c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 326c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct Literal { 327c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr Literal(const char *name) : name(name) {} 328c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith const char *name; 329c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 330c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct Expr { 331c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr Expr(Literal l) : IsLiteral(true), l(l) {} 332c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith bool IsLiteral; 333c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith union { 334c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith Literal l; 335c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith // ... 336c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 337c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 338c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct MulEq { 339c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr MulEq(Expr a, Expr b) : LHS(a), RHS(b) {} 340c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith Expr LHS; 341c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith Expr RHS; 342c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 343c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith constexpr MulEq operator*=(Expr a, Expr b) { return MulEq(a, b); } 344c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith Literal a("a"); 345c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith Literal b("b"); 346c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith MulEq c = a *= b; // ok 347c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 348c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith 349c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith// - a throw-expression (15.1) 350c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smithnamespace Throw { 351c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith struct S { 352c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith int n : (throw "hello", 10); // expected-error {{constant expression}} expected-note {{subexpression}} 353c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith }; 354c1c5f27c64dfc3332d53ad30e44d626e4f9afac3Richard Smith} 35563fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor 35663fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor// PR9999 35763fe6814f339df30b8463b39995947cbdf920e48Douglas Gregortemplate<bool v> 35863fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorclass bitWidthHolding { 35963fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorpublic: 36063fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor static const 36163fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor unsigned int width = (v == 0 ? 0 : bitWidthHolding<(v >> 1)>::width + 1); 36263fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor}; 36363fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor 36463fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorstatic const int width=bitWidthHolding<255>::width; 36563fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor 36663fe6814f339df30b8463b39995947cbdf920e48Douglas Gregortemplate<bool b> 36763fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorstruct always_false { 36863fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor static const bool value = false; 36963fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor}; 37063fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor 37163fe6814f339df30b8463b39995947cbdf920e48Douglas Gregortemplate<bool b> 37263fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorstruct and_or { 37363fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor static const bool and_value = b && and_or<always_false<b>::value>::and_value; 37463fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor static const bool or_value = !b || and_or<always_false<b>::value>::or_value; 37563fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor}; 37663fe6814f339df30b8463b39995947cbdf920e48Douglas Gregor 37763fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorstatic const bool and_value = and_or<true>::and_value; 37863fe6814f339df30b8463b39995947cbdf920e48Douglas Gregorstatic const bool or_value = and_or<true>::or_value; 379