gcc/testsuite/g++.dg/cpp1z/decomp11.C

   1 // Test for decltype of direct decomposition.
   2 // { dg-options -std=c++17 }
   3
   4 template <class,class> struct same_type;
   5 template <class T> struct same_type<T,T> {};
   6
   7 struct A {
   8   int i;
   9   const int ci = 42;
  10   mutable int mi;
  11   int& r = i;
  12   const int& cr = ci;
  13 } a;
  14
  15 void f() {
  16   auto [i,ci,mi,r,cr] = a;
  17
  18   same_type<decltype(i),int>{};
  19   same_type<decltype(ci),const int>{};
  20   same_type<decltype(mi),int>{};
  21   same_type<decltype(r),int&>{};
  22   same_type<decltype(cr),const int&>{};
  23 }
  24 void frr() {
  25   auto &&[i,ci,mi,r,cr] = a;
  26
  27   same_type<decltype(i),int>{};
  28   same_type<decltype(ci),const int>{};
  29   same_type<decltype(mi),int>{};
  30   same_type<decltype(r),int&>{};
  31   same_type<decltype(cr),const int&>{};
  32 }
  33 void fc() {
  34   const auto [i,ci,mi,r,cr] = a;
  35
  36   same_type<decltype(i),const int>{};
  37   same_type<decltype(ci),const int>{};
  38   same_type<decltype(mi),int>{};
  39   same_type<decltype(r),int&>{};
  40   same_type<decltype(cr),const int&>{};
  41 }
  42 void frc() {
  43   const A ca{};
  44   auto &[i,ci,mi,r,cr] = ca;
  45
  46   same_type<decltype(i),const int>{};
  47   same_type<decltype(ci),const int>{};
  48   same_type<decltype(mi),int>{};
  49   same_type<decltype(r),int&>{};
  50   same_type<decltype(cr),const int&>{};
  51 }