Hojun-Cho
85af051cd1
wwstage UNDER — aliaslookup's leaf-only first-match walk let a
cross-module leaf collision (`type invalid = !i32;` ahead of
`type invalid = !void;` in c.aliases) shadow module M's own
alias. Silent-correct-by-zero-init: the let-decl prologue zeroed
the slot 8B-wide (typeis8byteprimitive's void-aliased path,
post-#22), so MOVSXD on the misresolved !i32 produced the right
value while diverging from cstage's MOVQ — bootstrap byte-id
held until any caller bumped the alias-chain ordering. Mirrors
cstage scope_lookup_prefer (cmd/wcc/check.c:65); module-
qualified pkg.alias path unchanged.
Polarity catalog: wwstage UNDER — aliaslookup missing module-
preferring scope discipline. Convergence wwstage → cstage's
resolver pattern (rule 10; cstage already correct via
scope_lookup_prefer). Two-pass walk: same-module first, then
existing first-match fallback. Sea-of-stars shape preserved.
Surfaced by lib/strings landing: utf8's `type invalid = !void;`
and strconv's `type invalid = !i32;` registered in the same flat
c.aliases under one combined.ww, with strconv's later-registered
entry sitting at the head of the chain. utf8.next/decode's
`return e;` (e: invalid) packed via MOVSXD instead of MOVQ. Four
sites in main.s, contributing to 993/995 byte-id divergence in
the wwstage rebuild path.
Tests:
- 726_alias_leaf_collision row 1 pins MOVQ post-zero-init on
both stages and cstage↔wwstage cmp -s byte-id for the
`(invalid:!void via beta)` shape with `alpha.invalid = !i32`
seeded ahead in c.aliases. Sentinel-flip-verified: revert →
wwstage emits MOVSXD post-zero-init + cmp diverges.
- Row 2 (i32_local_read_keeps_movsxd) gates against future
symptom-fix attempts: legitimate `let i: i32; return (i:i64);`
must still emit MOVSXD on both stages (>=2 narrow signed loads
in the promote fn TEXT). Independent of the aliaslookup fix.
98/98 ok. 995_self_rebuild stays green (ww2==ww3==ww4 byte-id).