Viewing file:  concepts-lambda2.C (4.16 KB) -rw-r--r--
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// { dg-do compile { target c++20 } }
template<typename T>
concept False = false;
template<typename T>
concept C1 = __is_same_as(T, int)
|| __is_same_as(T, long long)
|| __is_same_as(T, char);
template<typename T>
concept IsNotLarge = !__is_same_as(T, long long);
template<typename T>
concept IsNotTiny = !__is_same_as(T, char);
template<IsNotLarge T>
struct Foo
{
static constexpr auto a = [](auto n) { return n; };
template<IsNotTiny S>
auto b()
{
return [](False auto n) { return n; };
}
};
template<IsNotTiny T>
struct Bar
{
static constexpr auto a =
[]<IsNotTiny R>(R t) { return t; }('a'); // { dg-error "no match" }
char b =
[]<IsNotTiny R>(R t) { return t; }('b'); // { dg-error "no match" }
static constexpr auto a2 =
[](char t) requires false { return t; }('a'); // { dg-error "no match" }
char b2 =
[](char t) requires false { return t; }('b'); // { dg-error "no match" }
};
template<IsNotLarge S>
S c =
[]<IsNotTiny R>(R t) { return t; }('c'); // { dg-error "no match" }
template<IsNotLarge S>
S c2 =
[](char t) requires false { return t; }('c'); // { dg-error "no match" }
Bar<long long> bar;
void test0()
{
auto bar_a = bar.a;
auto bar_b = bar.b;
auto c = ::c<char>;
auto bar_a2 = bar.a2;
auto bar_b2 = bar.b2;
auto c2 = ::c2<char>;
auto g0 = []<False T>(T t) { return t; };
auto g1 = []<typename T> requires False<T> (T t) { return t; };
auto g2 = []<typename T>(T t) requires False<decltype(t)> { return t; };
auto g3 = [](int t) requires False<decltype(t)> { return t; }; // { dg-error "non-templated" }
auto g4 = [](False auto t) { return t; };
auto g5 = [](auto t) requires False<decltype(t)> { return t; };
auto g6 = [](int t) requires False<int> { return t; }; // { dg-error "non-templated" }
auto g7 = [](int t) requires false { return t; }; // { dg-error "non-templated" }
g0(0); // { dg-error "no match" }
g1(0); // { dg-error "no match" }
g2(0); // { dg-error "no match" }
g3(0);
g4(0); // { dg-error "no match" }
g5(0); // { dg-error "no match" }
g6(0);
g7(0);
}
void test1()
{
int var{-1};
auto g0 = [&]<False T>(T t) { return t; };
auto g1 = [&]<typename T> requires False<T> (T t) { return t; };
auto g2 = [&]<typename T>(T t) requires False<decltype(t)> { return t; };
auto g3 = [&](int t) requires False<decltype(t)> { return t; }; // { dg-error "non-templated" }
auto g4 = [&](False auto t) { return t; };
auto g5 = [&](auto t) requires False<decltype(t)> { return t; };
auto g6 = [&](int t) requires False<int> { return t; }; // { dg-error "non-templated" }
auto g7 = [&](int t) requires false { return t; }; // { dg-error "non-templated" }
g0(0); // { dg-error "no match" }
g1(0); // { dg-error "no match" }
g2(0); // { dg-error "no match" }
g3(0);
g4(0); // { dg-error "no match" }
g5(0); // { dg-error "no match" }
g6(0);
g7(0);
}
void test2()
{
auto x = []<IsNotTiny T>(auto a, T t, auto b)
requires IsNotTiny<decltype(a)> && IsNotLarge<decltype(b)>
{ return a + t + (T)b; };
x(5LL, 2LL, 1);
x('0', 2LL, 1LL); // { dg-error "no match" }
x(5LL, '0', 1LL); // { dg-error "no match" }
x(5LL, 2LL, 1LL); // { dg-error "no match" }
}
void test3()
{
auto x = []<IsNotTiny T>(IsNotTiny auto a, T t, IsNotLarge auto b)
{ return a + t + (T)b; };
x(5LL, 2LL, 1);
x('0', 2LL, 1LL); // { dg-error "no match" }
x(5LL, '0', 1LL); // { dg-error "no match" }
x(5LL, 2LL, 1LL); // { dg-error "no match" }
}
void test4()
{
auto g = []<C1 T> requires IsNotTiny<T>(T t) -> T
requires IsNotLarge<decltype(t)> { return t; };
g(5.5); // { dg-error "no match" }
g('a'); // { dg-error "no match" }
g(1LL); // { dg-error "no match" }
}
void test5()
{
Foo<int> foo1;
foo1.a(5.5);
foo1.a(1LL);
foo1.b<char>(); // { dg-error "no match" }
foo1.b<long long>()(5); // { dg-error "no match" }
Foo<double> foo2;
foo2.a(5.5);
foo2.a(1LL);
foo2.b<char>(); // { dg-error "no match" }
foo2.b<long long>()(5); // { dg-error "no match" }
}
using Func = int(*)(int);
void test6()
{
Func f1 = [](int a) requires false { return a; }; // { dg-error "non-templated" }
Func f2 = [](auto a) requires false { return a; }; // { dg-error "cannot convert" }
}
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