[Bug c++/47851] New: [4.6 Regression] [C++0x] Incorrect decltype result for conditional operator

["mimomorin at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47851

           Summary: [4.6 Regression] [C++0x] Incorrect decltype result for
                    conditional operator
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mimomorin@gmail.com


Created attachment 23436
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23436
Test case

Suppose we have a code

    struct Type {};

    typedef Type const ConstType;

    struct ConvertibleToType {
        operator Type&() { return *reinterpret_cast<Type*>(this); }
    };

Then expression `true ? ConvertibleToType() : ConstType()` has type `Type`.
But `decltype(true ? ConvertibleToType() : ConstType())` is `Type const`.

Note that, in gcc 4.5, both the type of the expression and its `decltype` are
`Type`.
(In clang TOT, both are `Type const`.)