The bound returned mate-depth pruning must be accompanied by a defined
depth.
beta -= (beta <= curEval);
if(ff->checker == CK_NONE) killers[ply+1][0] = killers[ply+1][1] /* = killers[ply+1][2]*/ = 0;
else if(ply > 0) killers[ply+1][0] = killers[ply-1][0], killers[ply+1][1] = killers[ply-1][1]; // inherit killers after check+evasion
- if(-INF >= beta) { moveSP = oldSP; return -INF+1; }
+ if(-INF >= beta) { moveSP = oldSP; ff->depth = MAXPLY; return -INF+1; }
// check test