PR analyzer/93950 reports an ICE when pruning the path of a
-Wanalyzer-null-dereference diagnostic.
The root cause is a bug in the state-tracking code, in which the
variable of interest is tracked from the callee to a "nullptr" param
at the caller, whereupon we have an INTEGER_CST "variable", and
the attempt to look up its lvalue fails.
This code could use a rewrite; in the meantime this patch extends
the bulletproofing from g:8525d1f5
for PR analyzer/93544 to all of the various places where var can
be updated, fixing the ICE.
gcc/analyzer/ChangeLog:
PR analyzer/93950
* diagnostic-manager.cc
(diagnostic_manager::prune_for_sm_diagnostic): Assert that var is
either NULL or not a constant. When updating var, bulletproof
against constant values.
gcc/testsuite/ChangeLog:
PR analyzer/93950
* g++.dg/analyzer/pr93950.C: New test.
