[Bug c++/87408] Enhance -Wunused-value to catch more complex expressions

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87408

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-09-24
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Our warning talks about the statement, and without interprocedural analysis it
can't see that get() doesn't have an effect. Clang's warning is better because
it doesn't say anything about whether get() has an effect, just that get()->a
doesn't use the result of the class member access.