def xs:[_]T=arrlit was sized 0 (no DATA emitted, garbage indexed reads) on BOTH stages, byte-id-identical: #7 wired [_] length-inference only on the let decl path, never def. cstage check.c N_DEF pass-2 infers the length from the initialiser and re-points both d->type and the SK_DEF Sym (an indexed read resolves the def through its Sym); wwstage check.ww runs inferarraylen before resolvewalk. Checker-only — cgen lays the DATA correctly once the length is stamped. w6c and wwdump combined.ww regen'd (both embed the wcc checker).
Pin: table-driven test/wcc/814_def_arr_infer_len (index reads int/u8/2d + 1-elem edge + negative build-fail), teeth-proven against a reverted inference. Filed separately, not folded (rule-11): def-global .len GAP-A (#7 cgdot twin), def str-array element DATA GAP-B (#270), [0]T-vs-[_] alen==0 conflation (pre-existing in the #7 let path too).