Adds the bulk of Go's type-expression grammar:
[]T → (list :ty-slice T)
[N]T → (list :ty-array N T) — N is an expr
map[K]V → (list :ty-map K V)
chan T → (list :ty-chan :both T)
chan<- T → (list :ty-chan :send T)
<-chan T → (list :ty-chan :recv T)
gp-parse-type now dispatches on the head token: *, [, map, chan, <-,
or ident; each branch recurses for nested types. Channel direction
is encoded as :both / :send / :recv (Go-specific tag).
Coverage: nested types end-to-end — []*T, [][]int, map[string][]int,
chan map[K]V, *[]int — all via the v.(T) assertion carrier.
Logged a concrete kit-gap proposal in plans/go-on-sx.md Blockers for
canonical type-node shapes. The first six (:ty-name, :ty-sel, :ty-ptr,
:ty-slice, :ty-array, :ty-map) are universal across statically-typed
guests and worth promoting on the next consumer; channel/func shapes
stay guest-specific until a second user.
Phase 2 parse acceptance bar (80+ tests) crossed: parse 81/81, total
210/210. Func / struct / interface types and full decls + stmts still
keep Phase 2 open.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>