[Bug c++/92105] [7/8/9/10 Regression] decltype(decltype(decltype)) prints exponential number of fix-it hints

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92105

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2019-10-15
      Known to work|                            |6.5.0
     Ever confirmed|0                           |1
      Known to fail|                            |10.0, 7.4.0, 8.3.0, 9.2.0

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
For that last example GCC 6 prints simply:

dt.cc:1:10: error: expected primary-expression before 'decltype'

decltype(decltype(decltype(decltype(decltype(decltype(decltype(decltype(decltype(decltype)))))))))
x = 42;
          ^~~~~~~~
dt.cc:1:10: error: expected ')' before 'decltype'
dt.cc:1:1: error: expected unqualified-id before 'decltype'

decltype(decltype(decltype(decltype(decltype(decltype(decltype(decltype(decltype(decltype)))))))))
x = 42;
 ^~~~~~~~