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84 lines
3.2 KiB
84 lines
3.2 KiB
4 months ago
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// RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -std=c++11 -verify %s
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// If an expression of literal class type is used in a context where an integral
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// constant expression is required, then that class type shall have a single
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// non-explicit conversion function to an integral or unscoped enumeration type
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namespace std_example {
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struct A {
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constexpr A(int i) : val(i) { }
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constexpr operator int() const { return val; } // expected-note {{here}}
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constexpr operator long() const { return 43; } // expected-note {{here}}
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private:
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int val;
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};
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template<int> struct X { };
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constexpr A a = 42;
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X<a> x; // ok, unique conversion to int
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int ary[a]; // expected-error {{ambiguous conversion from type 'const std_example::A' to an integral or unscoped enumeration type}}
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}
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struct OK {
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constexpr OK() {}
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constexpr operator int() const { return 8; }
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} constexpr ok;
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extern struct Incomplete incomplete; // expected-note 5{{forward decl}}
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struct Explicit {
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constexpr Explicit() {}
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constexpr explicit operator int() const { return 4; } // expected-note 5{{here}}
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} constexpr expl;
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struct Ambiguous {
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constexpr Ambiguous() {}
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constexpr operator int() const { return 2; } // expected-note 5{{here}}
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constexpr operator long() const { return 1; } // expected-note 5{{here}}
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} constexpr ambig;
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constexpr int test_ok = ok; // ok
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constexpr int test_explicit(expl); // ok
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constexpr int test_ambiguous = ambig; // ok
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static_assert(test_ok == 8, "");
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static_assert(test_explicit == 4, "");
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static_assert(test_ambiguous == 2, "");
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// [expr.new]p6: Every constant-expression in a noptr-new-declarator shall be
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// an integral constant expression
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auto new1 = new int[1][ok];
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auto new2 = new int[1][incomplete]; // expected-error {{incomplete}}
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auto new3 = new int[1][expl]; // expected-error {{explicit conversion}}
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auto new4 = new int[1][ambig]; // expected-error {{ambiguous conversion}}
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// [dcl.enum]p5: If the underlying type is not fixed [...] the initializing
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// value [...] shall be an integral constant expression.
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enum NotFixed {
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enum1 = ok,
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enum2 = incomplete, // expected-error {{incomplete}}
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enum3 = expl, // expected-error {{explicit conversion}}
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enum4 = ambig // expected-error {{ambiguous conversion}}
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};
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// [dcl.align]p2: When the alignment-specifier is of the form
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// alignas(assignment-expression), the assignment-expression shall be an
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// integral constant expression
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alignas(ok) int alignas1;
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alignas(incomplete) int alignas2; // expected-error {{incomplete}}
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alignas(expl) int alignas3; // expected-error {{explicit conversion}}
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alignas(ambig) int alignas4; // expected-error {{ambiguous conversion}}
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// [dcl.array]p1: If the constant-expression is present, it shall be an integral
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// constant expression
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int array1[ok];
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int array2[incomplete]; // expected-error {{incomplete}}
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int array3[expl]; // expected-error {{explicit conversion}}
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int array4[ambig]; // expected-error {{ambiguous conversion}}
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// [class.bit]p1: The constasnt-expression shall be an integral constant
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// expression
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struct Bitfields {
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int bitfield1 : ok;
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int bitfield2 : incomplete; // expected-error {{incomplete}}
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int bitfield3 : expl; // expected-error {{explicit conversion}}
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int bitfield4 : ambig; // expected-error {{ambiguous conversion}}
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};
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