clang/test/PCH/cxx1z-decomposition.cpp

   1 // No PCH:
   2 // RUN: %clang_cc1 -pedantic -std=c++1z -include %s -verify %s
   3 //
   4 // With PCH:
   5 // RUN: %clang_cc1 -pedantic -std=c++1z -emit-pch -fallow-pch-with-compiler-errors %s -o %t
   6 // RUN: %clang_cc1 -pedantic -std=c++1z -include-pch %t -fallow-pch-with-compiler-errors -verify %s
   7
   8 // RUN: %clang_cc1 -pedantic -std=c++1z -emit-pch -fallow-pch-with-compiler-errors -fpch-instantiate-templates %s -o %t
   9 // RUN: %clang_cc1 -pedantic -std=c++1z -include-pch %t -fallow-pch-with-compiler-errors -verify %s
  10
  11 #ifndef HEADER
  12 #define HEADER
  13
  14 template<typename T> auto decomp(const T &t) {
  15   auto &[a, b] = t;
  16   return a + b;
  17 }
  18
  19 struct Q { int a, b; };
  20 constexpr int foo(Q &&q) {
  21   auto &[a, b] = q;
  22   return a * 10 + b;
  23 }
  24
  25 auto [noinit]; // expected-error{{decomposition declaration '[noinit]' requires an initializer}}
  26
  27 #else
  28
  29 int arr[2];
  30 int k = decomp(arr);
  31
  32 static_assert(foo({1, 2}) == 12);
  33
  34 // expected-error@15 {{cannot decompose non-class, non-array type 'const int'}}
  35 int z = decomp(10); // expected-note {{instantiation of}}
  36
  37 #endif