[Bug c++/82728] [8 regression] Incorrect -Wunused-but-set-variable warning with a const

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82728

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Thu Jan 11 19:08:41 2018
New Revision: 256550

URL: https://gcc.gnu.org/viewcvs?rev=256550&root=gcc&view=rev
Log:
        PR c++/82728 - wrong -Wunused-but-set-variable

        PR c++/82799
        PR c++/83690
        * call.c (perform_implicit_conversion_flags): Call mark_rvalue_use.
        * decl.c (case_conversion): Likewise.
        * semantics.c (finish_static_assert): Call
        perform_implicit_conversion_flags.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-switch2.C
    trunk/gcc/testsuite/g++.dg/warn/Wunused-var-27.C
    trunk/gcc/testsuite/g++.dg/warn/Wunused-var-28.C
    trunk/gcc/testsuite/g++.dg/warn/Wunused-var-29.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/call.c
    trunk/gcc/cp/decl.c
    trunk/gcc/cp/semantics.c