The depth->=2 chained `t.m.l = s` struct-ident field copy selected its tail with (tail==4)?MOVL:(tail==1?MOVB:MOVQ), so every tail in {2,3,5,6,7} fell to an 8-byte MOVQ that over-wrote past the destination field — clobbering a @packed neighbour (t.m.l=s wrote s's slop over t.m.z: cstage exit 0 vs wwstage's correct 222) and diverging cs!=ww gate-blind. Replace with a descending 4/2/1 MOVL/MOVW/MOVB ladder comparing to ssz (the field's natural type-table size), aligning cstage UP to wwstage's sized ladder + cg_aggcopy. New table-driven gate 949_chained_dot_struct_copy_run (7 sizes x runtime-exit oracle on both drivers + cs==ww byte-id; negative-control proven).
Hojun-Cho
801d105c0f