https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96003
Nadav Har'El <nyh at math dot technion.ac.il> changed:
What |Removed |Added
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CC| |nyh at math dot technion.ac.il
--- Comment #27 from Nadav Har'El <nyh at math dot technion.ac.il> ---
I think this problem still exists at least in some form, and should be
reopened. It just hit the Seastar project, with gcc 11.1.1 -
https://github.com/scylladb/seastar/issues/914.
The problem there is that it uses C-style callbacks (of the c-ares library)
that cannot be modified; The callback gets a void* argument. We pass a C++'s
object's address into this void*, and then inside the callback function itself,
cast the void* back (using reinterpret_cast) to the object pointer - and then
attempt to run methods of this pointer. Here is where gcc 11.1.1. warns us that
this pointer may be a null (the message erroneously says "is a null") -
although I know for a fact it cannot be a null, and sadly even adding an
assert(p) to tell the compiler I'm sure it is not a null - doesn't help.
