84 lines · cpp
1// RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -std=c++11 -verify %s2 3// If an expression of literal class type is used in a context where an integral4// constant expression is required, then that class type shall have a single5// non-explicit conversion function to an integral or unscoped enumeration type6namespace std_example {7 8struct A {9 constexpr A(int i) : val(i) { }10 constexpr operator int() const { return val; } // expected-note {{here}}11 constexpr operator long() const { return 43; } // expected-note {{here}}12private:13 int val;14};15template<int> struct X { };16constexpr A a = 42;17X<a> x; // ok, unique conversion to int18int ary[a]; // expected-error {{ambiguous conversion from type 'const A' to an integral or unscoped enumeration type}}19 20}21 22struct OK {23 constexpr OK() {}24 constexpr operator int() const { return 8; }25} constexpr ok;26extern struct Incomplete incomplete; // expected-note 5{{forward decl}}27struct Explicit {28 constexpr Explicit() {}29 constexpr explicit operator int() const { return 4; } // expected-note 5{{here}}30} constexpr expl;31struct Ambiguous {32 constexpr Ambiguous() {}33 constexpr operator int() const { return 2; } // expected-note 5{{here}}34 constexpr operator long() const { return 1; } // expected-note 5{{here}}35} constexpr ambig;36 37constexpr int test_ok = ok; // ok38constexpr int test_explicit(expl); // ok39constexpr int test_ambiguous = ambig; // ok40 41static_assert(test_ok == 8, "");42static_assert(test_explicit == 4, "");43static_assert(test_ambiguous == 2, "");44 45// [expr.new]p6: Every constant-expression in a noptr-new-declarator shall be46// an integral constant expression47auto new1 = new int[1][ok];48auto new2 = new int[1][incomplete]; // expected-error {{incomplete}}49auto new3 = new int[1][expl]; // expected-error {{explicit conversion}}50auto new4 = new int[1][ambig]; // expected-error {{ambiguous conversion}}51 52// [dcl.enum]p5: If the underlying type is not fixed [...] the initializing53// value [...] shall be an integral constant expression.54enum NotFixed {55 enum1 = ok,56 enum2 = incomplete, // expected-error {{incomplete}}57 enum3 = expl, // expected-error {{explicit conversion}}58 enum4 = ambig // expected-error {{ambiguous conversion}}59};60 61// [dcl.align]p2: When the alignment-specifier is of the form62// alignas(assignment-expression), the assignment-expression shall be an63// integral constant expression64alignas(ok) int alignas1;65alignas(incomplete) int alignas2; // expected-error {{incomplete}}66alignas(expl) int alignas3; // expected-error {{explicit conversion}}67alignas(ambig) int alignas4; // expected-error {{ambiguous conversion}}68 69// [dcl.array]p1: If the constant-expression is present, it shall be an integral70// constant expression71int array1[ok];72int array2[incomplete]; // expected-error {{incomplete}}73int array3[expl]; // expected-error {{explicit conversion}}74int array4[ambig]; // expected-error {{ambiguous conversion}}75 76// [class.bit]p1: The constasnt-expression shall be an integral constant77// expression78struct Bitfields {79 int bitfield1 : ok;80 int bitfield2 : incomplete; // expected-error {{incomplete}}81 int bitfield3 : expl; // expected-error {{explicit conversion}}82 int bitfield4 : ambig; // expected-error {{ambiguous conversion}}83};84