haskell: Phase 8 — Read class stub (reads/readsPrec/read) (+3 tests, 10/10)

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

lib/haskell/tests/show.sx

@@ -41,4 +41,19 @@
       "buildJust3 s = showString \"Just \" (shows 3 s)\nmain = showParen True buildJust3 \"\""))
   "(Just 3)")
 
+(hk-test
+  "reads: stub returns empty list (null-check)"
+  (hk-deep-force (hk-run "main = show (null (reads \"42\"))"))
+  "True")
+
+(hk-test
+  "readsPrec: stub returns empty list"
+  (hk-deep-force (hk-run "main = show (null (readsPrec 0 \"True\"))"))
+  "True")
+
+(hk-test
+  "reads: type-checks in expression context (length)"
+  (hk-deep-force (hk-run "main = show (length (reads \"abc\"))"))
+  "0")
+
 {:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}