It can only be NULL if AvFILLp(isa_lin) is -1, and the code in the fast path
block will work cleanly in that case too.
AV* const isa_lin
= S_mro_get_linear_isa_c3(aTHX_ isa_item_stash, level + 1);
- if(items == 0 && AvFILLp(seqs) == -1 && AvARRAY(isa_lin)) {
+ if(items == 0 && AvFILLp(seqs) == -1) {
/* Only one parent class. For this case, the C3
linearisation is this class followed by the parent's
inearisation, so don't bother with the expensive