[Bug c++/83806] [6/7/8 Regression] Spurious -Wunused-but-set-parameter with nullptr

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83806

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-01-13
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |msebor at gcc dot gnu.org
      Known to work|                            |5.4.0
            Summary|Spurious                    |[6/7/8 Regression] Spurious
                   |unused-but-set-parameter    |-Wunused-but-set-parameter
                   |with nullptr                |with nullptr
     Ever confirmed|0                           |1
      Known to fail|                            |6.4.0, 7.2.0, 8.0

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Confirmed.  Introduced by r232436 (gcc 6.0.0):

r232436 | jason | 2016-01-15 10:57:07 -0500 (Fri, 15 Jan 2016) | 6 lines

        PR c++/69257
        * typeck.c (decay_conversion): Don't call mark_rvalue_use for
        array/function-to-pointer conversion.  Call
        complete_type_or_maybe_complain for lvalue-to-rvalue conversion.
        * call.c (convert_like_real): Print call context if
        decay_conversion errors.