File: cxx1z-decomposition.cpp

package info (click to toggle)
llvm-toolchain-15 1%3A15.0.6-4
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,554,644 kB
  • sloc: cpp: 5,922,452; ansic: 1,012,136; asm: 674,362; python: 191,568; objc: 73,855; f90: 42,327; lisp: 31,913; pascal: 11,973; javascript: 10,144; sh: 9,421; perl: 7,447; ml: 5,527; awk: 3,523; makefile: 2,520; xml: 885; cs: 573; fortran: 567
file content (33 lines) | stat: -rw-r--r-- 876 bytes parent folder | download | duplicates (29) 
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
 
// RUN: %clang_cc1 -std=c++1z -verify %s

struct A { int x, y; };
typedef int B[2];
struct C { template<int> int get(); };
struct D { int x, y, z; };
struct E { int *p, n; };

namespace std {
  using size_t = decltype(sizeof(0));
  template<typename> struct tuple_size;
  template<size_t, typename> struct tuple_element { using type = int; };
}

template<> struct std::tuple_size<C> { enum { value = 2 }; };

template<typename T> int decomp(T &t) { 
  auto &[a, b] = t; // expected-error {{type 'D' decomposes into 3 elements, but only 2 names were provided}}
  return a + b; // expected-error {{cannot initialize return object of type 'int' with an rvalue of type 'int *'}}
}

void test() {
  A a;
  B b;
  C c;
  D d;
  E e;
  decomp(a);
  decomp(b);
  decomp(c);
  decomp(d); // expected-note {{in instantiation of}}
  decomp(e); // expected-note {{in instantiation of}}
}