[Bug bootstrap/101574] gcc/sparseset.h:215:20: error: suggest parentheses around assignment used as truth value [-Werror=parentheses]

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101574

--- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> ---
The symptom in comment #6 does look similar to the problem discussed in
pr101292.  I haven't debugged it yet but when developing the warning control
patch I struggled with keeping the garbage collector from collecting the global
hash map between location_t and the nowarn_spec_t struct.  My suspicion is that
either the annotation on the hash_map isn't correct (it's a simple GTY("") so
it's hard to imagine what might be wrong with it), or the integration with the
garbage collector is incomplete (I had to change the hash_map definition itself
to let hash_map<location_t, nowarn_spec_t> even compile).