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230 lines
11 KiB
230 lines
11 KiB
// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify -Wno-unused-value
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template<typename T, typename U>
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constexpr bool is_same_v = false;
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template<typename T>
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constexpr bool is_same_v<T, T> = true;
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// We use a hack in this file to make the compiler print out the requires
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// expression after it has been instantiated - we put false_v<requires {...}> as
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// the requires clause of a class template, then instantiate the template.
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// The requirement will not be satisfied, and the explaining diagnostic will
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// print out false_v<requires {...}> in its raw form (the false_v serves to
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// prevent the diagnostic from elaborating on why the requires expr wasn't
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// satisfied).
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template<bool v>
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constexpr bool false_v = false;
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template<typename... Ts>
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using void_t = void;
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// Check that requires parameters are instantiated correctly.
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template<typename T> requires
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false_v<requires (T t) { requires is_same_v<decltype(t), int>; }>
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// expected-note@-1 {{because 'false_v<requires (int t) { requires is_same_v<decltype(t), int>; }>' evaluated to false}}
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// expected-note@-2 {{because 'false_v<requires (char t) { requires is_same_v<decltype(t), int>; }>' evaluated to false}}
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struct r1 {};
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using r1i1 = r1<int>; // expected-error {{constraints not satisfied for class template 'r1' [with T = int]}}
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using r1i2 = r1<char>; // expected-error {{constraints not satisfied for class template 'r1' [with T = char]}}
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// Check that parameter packs work.
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template<typename... Ts> requires
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false_v<requires (Ts... ts) {requires ((sizeof(ts) == 2) && ...);}>
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// expected-note@-1 {{because 'false_v<requires (short ts, unsigned short ts) { requires (sizeof (ts) == 2) && (sizeof (ts) == 2); }>'}}
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// expected-note@-2 {{because 'false_v<requires (short ts) { requires (sizeof (ts) == 2); }>' evaluated to false}}
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struct r2 {};
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using r2i1 = r2<short, unsigned short>; // expected-error {{constraints not satisfied for class template 'r2' [with Ts = <short, unsigned short>]}}
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using r2i2 = r2<short>; // expected-error {{constraints not satisfied for class template 'r2' [with Ts = <short>]}}
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template<typename... Ts> requires
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false_v<(requires (Ts ts) {requires sizeof(ts) != 0;} && ...)>
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// expected-note@-1 {{because 'false_v<requires (short ts) { requires sizeof (ts) != 0; } && requires (unsigned short ts) { requires sizeof (ts) != 0; }>' evaluated to false}}
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// expected-note@-2 {{because 'false_v<requires (short ts) { requires sizeof (ts) != 0; }>' evaluated to false}}
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struct r3 {};
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using r3i1 = r3<short, unsigned short>; // expected-error {{constraints not satisfied for class template 'r3' [with Ts = <short, unsigned short>]}}
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using r3i2 = r3<short>; // expected-error {{constraints not satisfied for class template 'r3' [with Ts = <short>]}}
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template<typename T>
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struct identity { using type = T; };
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namespace type_requirement {
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struct A {};
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// check that nested name specifier is instantiated correctly.
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template<typename T> requires false_v<requires { typename T::type; }> // expected-note{{because 'false_v<requires { typename identity<int>::type; }>' evaluated to false}}
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struct r1 {};
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using r1i = r1<identity<int>>; // expected-error{{constraints not satisfied for class template 'r1' [with T = identity<int>]}}
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// check that template argument list is instantiated correctly.
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template<typename T>
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struct contains_template {
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template<typename U> requires is_same_v<contains_template<T>, U>
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using temp = int;
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};
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template<typename T> requires
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false_v<requires { typename T::template temp<T>; }>
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// expected-note@-1 {{because 'false_v<requires { typename contains_template<int>::temp<contains_template<int> >; }>' evaluated to false}}
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// expected-note@-2 {{because 'false_v<requires { typename contains_template<short>::temp<contains_template<short> >; }>' evaluated to false}}
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struct r2 {};
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using r2i1 = r2<contains_template<int>>; // expected-error{{constraints not satisfied for class template 'r2' [with T = type_requirement::contains_template<int>]}}
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using r2i2 = r2<contains_template<short>>; // expected-error{{constraints not satisfied for class template 'r2' [with T = type_requirement::contains_template<short>]}}
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// substitution error occurs, then requires expr is instantiated again
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template<typename T>
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struct a {
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template<typename U> requires (requires { typename T::a::a; }, false)
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// expected-note@-1{{because 'requires { <<error-type>>; } , false' evaluated to false}}
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struct r {};
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};
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using ari = a<int>::r<short>; // expected-error{{constraints not satisfied for class template 'r' [with U = short]}}
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// Parameter pack inside expr
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template<typename... Ts> requires
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false_v<(requires { typename Ts::type; } && ...)>
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// expected-note@-1 {{because 'false_v<requires { typename identity<short>::type; } && requires { typename identity<int>::type; } && requires { <<error-type>>; }>' evaluated to false}}
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struct r5 {};
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using r5i = r5<identity<short>, identity<int>, short>; // expected-error{{constraints not satisfied for class template 'r5' [with Ts = <identity<short>, identity<int>, short>]}}
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template<typename... Ts> requires
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false_v<(requires { typename void_t<Ts>; } && ...)> // expected-note{{because 'false_v<requires { typename void_t<int>; } && requires { typename void_t<short>; }>' evaluated to false}}
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struct r6 {};
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using r6i = r6<int, short>; // expected-error{{constraints not satisfied for class template 'r6' [with Ts = <int, short>]}}
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template<typename... Ts> requires
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false_v<(requires { typename Ts::template aaa<Ts>; } && ...)>
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// expected-note@-1 {{because 'false_v<requires { <<error-type>>; } && requires { <<error-type>>; }>' evaluated to false}}
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struct r7 {};
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using r7i = r7<int, A>; // expected-error{{constraints not satisfied for class template 'r7' [with Ts = <int, type_requirement::A>]}}
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}
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namespace expr_requirement {
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// check that compound/simple requirements are instantiated correctly.
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template<typename T> requires false_v<requires { sizeof(T); { sizeof(T) }; }>
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// expected-note@-1 {{because 'false_v<requires { sizeof(int); { sizeof(int) }; }>' evaluated to false}}
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// expected-note@-2 {{because 'false_v<requires { <<error-expression>>; { sizeof(T) }; }>' evaluated to false}}
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struct r1 {};
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using r1i1 = r1<int>; // expected-error{{constraints not satisfied for class template 'r1' [with T = int]}}
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using r1i2 = r1<void>; // expected-error{{constraints not satisfied for class template 'r1' [with T = void]}}
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// substitution error occurs in expr, then expr is instantiated again.
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template<typename T>
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struct a {
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template<typename U> requires (requires { sizeof(T::a); }, false) // expected-note{{because 'requires { <<error-expression>>; } , false' evaluated to false}}
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struct r {};
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};
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using ari = a<int>::r<short>; // expected-error{{constraints not satisfied for class template 'r' [with U = short]}}
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// check that the return-type-requirement is instantiated correctly.
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template<typename T, typename U = int>
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concept C1 = is_same_v<T, U>;
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template<typename T> requires false_v<requires(T t) { { t } -> C1<T>; }>
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// expected-note@-1 {{because 'false_v<requires (int t) { { t } -> C1<int>; }>' evaluated to false}}
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// expected-note@-2 {{because 'false_v<requires (double t) { { t } -> C1<double>; }>' evaluated to false}}
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struct r2 {};
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using r2i1 = r2<int>; // expected-error{{constraints not satisfied for class template 'r2' [with T = int]}}
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using r2i2 = r2<double>; // expected-error{{constraints not satisfied for class template 'r2' [with T = double]}}
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// substitution error occurs in return type requirement, then requires expr is
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// instantiated again.
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template<typename T>
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struct b {
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template<typename U> requires (requires { { 0 } -> C1<typename T::a>; }, false) // expected-note{{because 'requires { { 0 } -> <<error-type>>; } , false' evaluated to false}}
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struct r {};
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};
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using bri = b<int>::r<short>; // expected-error{{constraints not satisfied for class template 'r' [with U = short]}}
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template<typename... Ts> requires
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false_v<(requires { { 0 } noexcept -> C1<Ts>; } && ...)>
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// expected-note@-1 {{because 'false_v<requires { { 0 } noexcept -> C1<int>; } && requires { { 0 } noexcept -> C1<unsigned int>; }>' evaluated to false}}
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struct r3 {};
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using r3i = r3<int, unsigned int>; // expected-error{{constraints not satisfied for class template 'r3' [with Ts = <int, unsigned int>]}}
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template<typename T>
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struct r4 {
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constexpr int foo() {
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if constexpr (requires { this->invalid(); })
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return 1;
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else
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return 0;
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}
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constexpr void invalid() requires false { }
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};
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static_assert(r4<int>{}.foo() == 0);
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}
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namespace nested_requirement {
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// check that constraint expression is instantiated correctly
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template<typename T> requires false_v<requires { requires sizeof(T) == 2; }> // expected-note{{because 'false_v<requires { requires sizeof(int) == 2; }>' evaluated to false}}
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struct r1 {};
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using r1i = r1<int>; // expected-error{{constraints not satisfied for class template 'r1' [with T = int]}}
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// substitution error occurs in expr, then expr is instantiated again.
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template<typename T>
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struct a {
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template<typename U> requires
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(requires { requires sizeof(T::a) == 0; }, false) // expected-note{{because 'requires { requires <<error-expression>>; } , false' evaluated to false}}
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struct r {};
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};
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using ari = a<int>::r<short>; // expected-error{{constraints not satisfied for class template 'r' [with U = short]}}
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// Parameter pack inside expr
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template<typename... Ts> requires
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false_v<(requires { requires sizeof(Ts) == 0; } && ...)>
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// expected-note@-1 {{because 'false_v<requires { requires sizeof(int) == 0; } && requires { requires sizeof(short) == 0; }>' evaluated to false}}
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struct r2 {};
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using r2i = r2<int, short>; // expected-error{{constraints not satisfied for class template 'r2' [with Ts = <int, short>]}}
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}
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// Parameter pack inside multiple requirements
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template<typename... Ts> requires
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false_v<(requires { requires sizeof(Ts) == 0; sizeof(Ts); } && ...)>
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// expected-note@-1 {{because 'false_v<requires { requires sizeof(int) == 0; sizeof(Ts); } && requires { requires sizeof(short) == 0; sizeof(Ts); }>' evaluated to false}}
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struct r4 {};
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using r4i = r4<int, short>; // expected-error{{constraints not satisfied for class template 'r4' [with Ts = <int, short>]}}
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template<typename... Ts> requires
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false_v<(requires(Ts t) { requires sizeof(t) == 0; t++; } && ...)>
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// expected-note@-1 {{because 'false_v<requires (int t) { requires sizeof (t) == 0; t++; } && requires (short t) { requires sizeof (t) == 0; t++; }>' evaluated to false}}
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struct r5 {};
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using r5i = r5<int, short>; // expected-error{{constraints not satisfied for class template 'r5' [with Ts = <int, short>]}}
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template<typename T> requires
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false_v<(requires(T t) { T{t}; })> // T{t} creates an "UnevaluatedList" context.
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// expected-note@-1 {{because 'false_v<(requires (int t) { int{t}; })>' evaluated to false}}
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struct r6 {};
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using r6i = r6<int>;
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// expected-error@-1 {{constraints not satisfied for class template 'r6' [with T = int]}}
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