[Bug c++/56958] Spurious set but not used variable warning in empty pack expansion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56958

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-26 14:23:27 UTC ---
Well, you aren't using spurious, are you?  Because t + spurious... expands to
nothing.

If mark_exp_read isn't called while processing_template_decl because the
expression is type dependent, and during instantiation is lost altogether, not
sure where could we call mark_rvalue_use etc.