exprtype's N_IDENT branch resolved a bare value-ident through the
flat-scope scopelookup, which bucket-walks and returns whichever
same-leaf symbol heads the bucket (the last-registered one). Under a
foreign curmod that binds a same-named symbol from the wrong module
and drags in its declaration's type: resolving `read` to io.read while
checking os pulled io.read's (size|eof|error) return node, whose bare
`error` then bound strconv.error instead of io.error. The mistyped
union variant made the tagged-tag remap's flatvariantidxt return -1
(correctly: the union held the wrong type), collapsing the tag to 0 —
the #226 fmt cs/ww asm divergence.
Resolve through scopelookupprefer(c.cur, c.curmod, e.str), preferring
the current module, mirroring cstage cmd/wcc/check.c:66
scope_lookup_prefer. Sibling bare-leaf sites already migrated: #56
(N_CALL callee), #53 (bare TNAME).
#226 is thereby an instance of #55, not a nominal-identity gap:
io.error is already a sound sym-cached singleton. The remaining
bare-leaf sites (N_DOT-callee leaf, varianterr, scruttype) and the
cgen-side cgident analogue are tracked separately. fmt's 777/780/781
stay STAGE_CS pending a separate spread-union residual.
test/wcc/794: cross-module bare-leaf value-ident, reject->accept
polarity (w6c_ww must accept the cstage-emitted combined); no byte-id
assertion as the minimal value-ident also trips the open cgen-side
cgident bug.
Hojun-Cho
f8aebc045d