Mercurial > hg > CbC > CbC_gcc

comparison gcc/testsuite/g++.dg/cpp2a/concepts-decltype.C @ 145:1830386684a0

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
parents
children
comparison
equal deleted inserted replaced
131:84e7813d76e9 145:1830386684a0
1 // { dg-do compile { target c++2a } }
2
3 // Tests constrained decltype(auto).
4
5 template<typename T>
6 concept Type = true;
7
8 template<typename T>
9 concept Int = __is_same_as(T, int);
10
11 template<typename T, typename U>
12 concept SameAs = __is_same_as(T, U);
13
14 template<typename T, typename U>
15 requires SameAs<T, U>
16 constexpr bool check = true;
17
18 int z = 0;
19 const int cz = 0;
20
21 Type decltype(auto) x1 = 0;
22 static_assert(check<decltype(x1), int>);
23 Type decltype(auto) x2 = z;
24 static_assert(check<decltype(x2), int>);
25 Type decltype(auto) x3 = (z);
26 static_assert(check<decltype(x3), int&>);
27 Type decltype(auto) x4 = cz;
28 static_assert(check<decltype(x4), const int>);
29 Type decltype(auto) x5 = (cz);
30 static_assert(check<decltype(x5), const int&>);
31
32 Type decltype(auto) f1() { return 0; }
33 static_assert(check<decltype(f1()), int>);
34 Type decltype(auto) f2() { return z; }
35 static_assert(check<decltype(f2()), int>);
36 Type decltype(auto) f3() { return (z); }
37 static_assert(check<decltype(f3()), int&>);
38 Type decltype(auto) f4() { return cz; }
39 static_assert(check<decltype(f4()), int>); // Top-level const is removed?
40 Type decltype(auto) f5() { return (cz); }
41 static_assert(check<decltype(f5()), const int&>);
42
43 bool b = true;
44 const bool cb = true;
45
46 Int decltype(auto) b1 = true; // { dg-error "deduced initializer" }
47 Int decltype(auto) b2 = (b); // { dg-error "deduced initializer" }
48 Int decltype(auto) b3 = (cb); // { dg-error "deduced initializer" }
49
50 Int decltype(auto) g1() { } // { dg-error "deduced return type" }
51 Int decltype(auto) g2() { return; } // { dg-error "deduced return type" }
52 Int decltype(auto) g3() { return true; } // { dg-error "deduced return type" }
53 int g4(Type decltype(auto) x) { return 0; } // { dg-error "cannot declare" }
54 int g5(decltype(auto) x) { return 0; } // { dg-error "cannot declare" }
55
56 template<Type decltype(auto) X, typename T>
57 requires SameAs<decltype(X), T>
58 constexpr bool deduced_as = true;
59
60 constexpr int Z = 10;
61
62 static_assert(deduced_as<0, int>);
63 static_assert(deduced_as<0, int&>); // { dg-error "invalid variable template" }
64 static_assert(deduced_as<Z, const int>);
65 static_assert(deduced_as<(Z), const int>); // { dg-error "invalid variable template" }
66 static_assert(deduced_as<(Z), const int&>);
67