Commits on Feb 8, 2022

1. Fixed #425: Show the correct reference type for structured bindings. …

   This patch changes the behavior of how the resulting reference type of a
   binding is determined. Now, the code uses the holding variables
   type information of a `BindingDecl`. This seems to be consistent with
   what Clang does.
   
   The reference kind of a binding is determined by the declaration of the
   structured binding.
   
   In [dcl.struct.bind] the standard says that the reference type for a
   binding is an lvalue reference if the initializer is an lvalue and
   otherwise a rvalue reference. The initializer here donates to the hidden
   object, referenced as e. WE declare this implicitly by declaring the
   structured binding.
   
   We get an rvalue reference in case we declare the structured binding as
   a non-reference like this:
   ```
   auto [a, b, c]
   ```
   
   We get an lvalue reference if the structured binding is declared as
   this:
   
   ```
   auto& [a, b, c]
   ```
   
   In the rvalue case we could profit from move because the contents of the
   implicitly created object can be moved out.
   
   If we have a reference to the original object moving wouldn't be a good
   ting to do, hence an lvalue reference.
   
   `std::get` has overloads for both l- and rvalues and returns the
   respective reference type for each overload.
   
   This behavior is observable thanks to #381 which shows the implicit cast
   of the hidden object to a rvalue.

   

   andreasfertig committed Feb 8, 2022
   Configuration menu

   • View commit details
   • Copy full SHA for f317d9a
   • Browse repository at this point

   Copy the full SHA

   f317d9a View commit details

   Browse the repository at this point in the history