An explicit [N]T = [init] with more initializers than N silently
mis-compiled for N==0: the over-fill length-mismatch check was suppressed
when alen==0, because alen==0 doubles as the [_] infer-sentinel after
resolve_type collapses the two. So def/let [0]int=[1,2] silently resized
(cstage exit 2) or OOB-read/segfaulted (wwstage) instead of the loud
length-mismatch that [N]=[init>N] gets everywhere else.
The AST keeps the distinction the Type loses: [_] leaves the N_TARRAY
length-child NULL, an explicit [N] carries N_INTLIT. cstage adds an
is_infer_arr() helper, drops the alen>0 exemption at the over-fill check,
and gates the 4 infer-resize/no-init sites on is_infer_arr so an explicit
[0] flows to the over-fill -> loud. wwstage flips the one shared count
gate (checkarrlitfits) from declen>0 to arrtn.rhs!=nil, which also
dissolves a wwstage local-resize/module-OOB inconsistency.
[_] inference, [0]=[] empty, and [_]-no-init louding all preserved.
Under-long (count<N) stays out of scope (#10). byte-id 990-997 8/8.
test/wcc/820 table-driven; its one empty-[0] global row carves out
byte-id (pre-existing spurious-DATAW divergence, task #15).
Hojun-Cho
29a2ab2a72