resolvealias only walked N_TNAME with unqualified names; cross-module
type aliases (parser emits them as one TNAME with str="pkg.alias"
via parse.ww:258-265 joindotted) returned the AST verbatim, and
checkisas at :1098-1108 then flagged "operand is not a tagged union"
on every `match (x: lib.maybe) { ... }` shape.
resolvealias now recognizes the joined-dotted form: split on the
rightmost '.', scopelookupinmodule(c.cur, head, leaf), recurse if
the body is itself an alias. Mirrors cstage resolve_typename at
cmd/wcc/check.c:74-83.
scruttype gains an N_DOT scrutinee arm — `match (pkg.var) { ... }`
or `pkg.var is T` now resolve through scopelookupinmodule. Module
head gating distinguishes top-level imported sym refs from struct
field access (both spell as N_DOT in the AST).
Standalone correctness fix; surfaces no current fixture failure
(those were enum-int reinterprets, tracked separately as #52). Sets
up #50 to wire checkfile into the wwstage cgen pipeline once #52
also lands.
Hojun-Cho
c7c756d9c8