| 1 | // RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -std=c++11 -verify %s |
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| 2 | |
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| 3 | // If an expression of literal class type is used in a context where an integral |
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| 4 | // constant expression is required, then that class type shall have a single |
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| 5 | // non-explicit conversion function to an integral or unscoped enumeration type |
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| 6 | namespace std_example { |
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| 7 | |
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| 8 | struct A { |
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| 9 | constexpr A(int i) : val(i) { } |
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| 10 | constexpr operator int() const { return val; } |
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| 11 | constexpr operator long() const { return 43; } |
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| 12 | private: |
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| 13 | int val; |
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| 14 | }; |
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| 15 | template<int> struct X { }; |
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| 16 | constexpr A a = 42; |
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| 17 | X<a> x; // ok, unique conversion to int |
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| 18 | int ary[a]; // expected-error {{size of array has non-integer type 'const std_example::A'}} |
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| 19 | |
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| 20 | } |
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| 21 | |
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| 22 | struct OK { |
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| 23 | constexpr OK() {} |
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| 24 | constexpr operator int() const { return 8; } |
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| 25 | } constexpr ok; |
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| 26 | extern struct Incomplete incomplete; // expected-note 4{{forward decl}} |
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| 27 | struct Explicit { |
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| 28 | constexpr Explicit() {} |
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| 29 | constexpr explicit operator int() const { return 4; } // expected-note 4{{here}} |
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| 30 | } constexpr expl; |
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| 31 | struct Ambiguous { |
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| 32 | constexpr Ambiguous() {} |
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| 33 | constexpr operator int() const { return 2; } // expected-note 4{{here}} |
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| 34 | constexpr operator long() const { return 1; } // expected-note 4{{here}} |
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| 35 | } constexpr ambig; |
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| 36 | |
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| 37 | constexpr int test_ok = ok; // ok |
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| 38 | constexpr int test_explicit(expl); // ok |
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| 39 | constexpr int test_ambiguous = ambig; // ok |
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| 40 | |
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| 41 | static_assert(test_ok == 8, ""); |
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| 42 | static_assert(test_explicit == 4, ""); |
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| 43 | static_assert(test_ambiguous == 2, ""); |
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| 44 | |
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| 45 | // [expr.new]p6: Every constant-expression in a noptr-new-declarator shall be |
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| 46 | // an integral constant expression |
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| 47 | auto new1 = new int[1][ok]; |
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| 48 | auto new2 = new int[1][incomplete]; // expected-error {{incomplete}} |
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| 49 | auto new3 = new int[1][expl]; // expected-error {{explicit conversion}} |
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| 50 | auto new4 = new int[1][ambig]; // expected-error {{ambiguous conversion}} |
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| 51 | |
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| 52 | // [dcl.enum]p5: If the underlying type is not fixed [...] the initializing |
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| 53 | // value [...] shall be an integral constant expression. |
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| 54 | enum NotFixed { |
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| 55 | enum1 = ok, |
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| 56 | enum2 = incomplete, // expected-error {{incomplete}} |
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| 57 | enum3 = expl, // expected-error {{explicit conversion}} |
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| 58 | enum4 = ambig // expected-error {{ambiguous conversion}} |
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| 59 | }; |
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| 60 | |
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| 61 | // [dcl.align]p2: When the alignment-specifier is of the form |
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| 62 | // alignas(assignment-expression), the assignment-expression shall be an |
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| 63 | // integral constant expression |
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| 64 | alignas(ok) int alignas1; |
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| 65 | alignas(incomplete) int alignas2; // expected-error {{incomplete}} |
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| 66 | alignas(expl) int alignas3; // expected-error {{explicit conversion}} |
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| 67 | alignas(ambig) int alignas4; // expected-error {{ambiguous conversion}} |
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| 68 | |
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| 69 | // [dcl.array]p1: If the constant-expression is present, it shall be an integral |
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| 70 | // constant expression |
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| 71 | // FIXME: The VLA recovery results in us giving diagnostics which aren't great |
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| 72 | // here. |
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| 73 | int array1[ok]; |
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| 74 | int array2[incomplete]; // expected-error {{non-integer type}} |
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| 75 | int array3[expl]; // expected-error {{non-integer type}} |
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| 76 | int array4[ambig]; // expected-error {{non-integer type}} |
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| 77 | |
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| 78 | // [class.bit]p1: The constasnt-expression shall be an integral constant |
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| 79 | // expression |
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| 80 | struct Bitfields { |
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| 81 | int bitfield1 : ok; |
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| 82 | int bitfield2 : incomplete; // expected-error {{incomplete}} |
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| 83 | int bitfield3 : expl; // expected-error {{explicit conversion}} |
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| 84 | int bitfield4 : ambig; // expected-error {{ambiguous conversion}} |
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| 85 | }; |
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| 86 | |
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