tinfofornode's TNAME arm collapsed aliases to their underlying tinfo; flip
it to build a per-decl TY_NAMED wrapper cached on sym.type_, so every TNAME
resolving to the same decl yields one tinfo pointer -- ptr-identity =
nominal identity. Mirrors cstage's two-phase type_named (cmd/wcc/check.c:
1900-1929, resolve_typename :60-88): create the NAMED, pre-bind sym.type_
BEFORE resolving under (self-ref cycle-break, e.g. `type node = struct
{next: *node}`), then patch under + copy size/align/slotsize off the
immediate body. CHAINS not flatten (`type a=b` gives under=NAMED(b)),
matching resolve_typename returning the inner NAMED.
aliassym factored out of resolvealias for the one-level decl lookup;
resolvealias delegates and is behaviorally identical.
Semantically INERT until typeeq consumes nominal identity (step 3, #16) --
live type equality today is the AST-keyed typeeqast, and typeeq has no live
callers. The #63 structural-walker peels + cstage-mirrored single-if peels
keep all tinfo.kind sites correct with NAMED flowing -- byte-id 990-997
unchanged (133/133, independently re-confirmed on a quiescent tree).
Hojun-Cho
3866ea24f5