;; instance-where.sx — Phase 13: where-clauses inside instance bodies.

(hk-test
  "instance method body with where-helper (Bool)"
  (hk-deep-force
    (hk-run
      "class Greet a where\n  greet :: a -> String\ninstance Greet Bool where\n  greet x = mkMsg x\n    where mkMsg True = \"yes\"\n          mkMsg False = \"no\"\nmain = greet True"))
  "yes")

(hk-test
  "instance method body with where-helper (False branch)"
  (hk-deep-force
    (hk-run
      "class Greet a where\n  greet :: a -> String\ninstance Greet Bool where\n  greet x = mkMsg x\n    where mkMsg True = \"yes\"\n          mkMsg False = \"no\"\nmain = greet False"))
  "no")

(hk-test
  "instance method body with where-binding referenced multiple times"
  (hk-deep-force
    (hk-run
      "class Twice a where\n  twice :: a -> Int\ninstance Twice Int where\n  twice x = h + h\n    where h = x + 1\nmain = twice 5"))
  12)

(hk-test
  "instance method body with multi-binding where"
  (hk-deep-force
    (hk-run
      "class Calc a where\n  calc :: a -> Int\ninstance Calc Int where\n  calc x = a + b\n    where a = x * 2\n          b = x + 1\nmain = calc 3"))
  10)

{:fails hk-test-fails :pass hk-test-pass :fail hk-test-fail}