File: concepts-requires16.C

package info (click to toggle)
gcc-arm-none-eabi 15%3A14.2.rel1-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 1,099,328 kB
  • sloc: cpp: 3,627,108; ansic: 2,571,498; ada: 834,230; f90: 235,082; makefile: 79,231; asm: 74,984; xml: 51,692; exp: 39,736; sh: 33,298; objc: 15,629; python: 15,069; fortran: 14,429; pascal: 7,003; awk: 5,070; perl: 3,106; ml: 285; lisp: 253; lex: 204; haskell: 135
file content (47 lines) | stat: -rw-r--r-- 1,102 bytes parent folder | download | duplicates (2) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 
// { dg-do compile { target c++20 } }

// A poor mans Integral concept.
template<typename T>
concept Integral = __is_same_as(T, int);

template<int N>
concept Nonnegative = N >= 0;

template<typename... Args>
concept UnaryPack = (sizeof...(Args) == 1);

template<typename... Args>
  requires Integral<Args...> // { dg-error "non-pack parameter" }
void f1();

template<typename... Args>
  requires Integral<Args>... // { dg-error "parameter packs not expanded|expected unqualified-id" }
void f2();

template<typename... Args>
  requires (Integral<Args> && ...)
void f3() { }

template<Integral... Args>
void f4() { }

// FIXME: This syntax is likely to be made invalid.
template<Nonnegative... Args> // { dg-error "does not constrain a type" }
void f5() { }

template<UnaryPack Arg> // requires UnaryPack<Arg>
void f6() { }

template<UnaryPack... Args> // requires (... && UnaryPack<Args>)
void f7() { }

void driver()
{
  f1<int, int>(); // { dg-error "" }
  f3<int, int>();
  f3<int, void>(); // { dg-error "" }
  f4<int, int>();
  f4<int, void>(); // { dg-error "" }
  f7<int>();
  f7<int, int>();
}