- formatter: global format mutex becomes a sync.Pool of doc arenas, so concurrent formats stop serializing; pinned by concurrency tests under -race - syntax: export IsKeyword, IsTypeKeyword, PrevReal, NextReal; source, formatter, and parser drop their private copies - lsp/source: CycleCheck reads Snapshot.Dependents off the COW include graph instead of rebuilding its own reachability; checker-level tests pin code, severity, and reported edges - doc: delete the unused heap-constructor API; print tests port to the arena and catch Arena.Join(nil-parts) building a nil Doc concat that crashed the printer - main: add missing --set-separator / --break-set flags - ci: run go test -race