haskell: Phase 11 — tests/map.sx (26/26, plan ≥20)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plans/haskell-completeness.md

@@ -190,9 +190,12 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
 - [x] Updating: `adjust`, `insertWith`, `insertWithKey`, `alter`.
 - [x] Module wiring: `import Data.Map` and `import qualified Data.Map as Map`
   resolve to the `map.sx` namespace dict in the eval import handler.
-- [ ] Unit tests in `lib/haskell/tests/map.sx` (≥ 20 tests: empty, singleton,
-  insert + lookup hit/miss, delete root, fromList with duplicates,
-  toAscList ordering, unionWith, foldlWithKey).
+- [x] Unit tests in `lib/haskell/tests/map.sx` (26 tests, well past ≥20 target:
+  empty/singleton/insert/lookup hit&miss/overwrite/delete/member at the SX
+  level, fromList with duplicates last-wins, toAscList ordering, elems in
+  order, unionWith/intersectionWith/difference, foldlWithKey/mapWithKey/
+  filterWithKey, adjust/insertWith/alter, plus 4 end-to-end tests via
+  `import qualified Data.Map as Map`.)
 - [ ] Conformance programs:
   - `wordfreq.hs` — word-frequency histogram using `Data.Map`. Source from
     Rosetta Code "Word frequency" Haskell entry.
@@ -304,6 +307,12 @@ No OCaml changes are needed. The view type is fully representable as an SX dict.
 
 _Newest first._
 
+**2026-05-07** — Phase 11 unit tests `tests/map.sx` (26/26):
+- 22 SX-level direct calls (empty/singleton/insert/lookup/delete/member/
+  fromList+duplicates/toAscList/elems/unionWith/intersectionWith/difference/
+  foldlWithKey/mapWithKey/filterWithKey/adjust/insertWith/alter) plus 4
+  end-to-end via `import qualified Data.Map as Map`. Plan asked for ≥20.
+
 **2026-05-07** — Phase 11 module wiring: `import Data.Map`:
 - Added `hk-bind-data-map!` helper in `eval.sx` that registers
   `<alias>.empty/singleton/insert/lookup/member/size/null/delete` as Haskell