28 lines
999 B
Haskell
28 lines
999 B
Haskell
{-# LANGUAGE QuasiQuotes, OverloadedStrings #-}
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module Core.HindleyMilnerSpec
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( spec
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)
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where
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----------------------------------------------------------------------------------
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import Core.Syntax
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import Core.TH (coreExpr)
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import Core.HindleyMilner (infer, TypeError(..), HMError)
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import Test.Hspec
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----------------------------------------------------------------------------------
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-- TODO: more tests. preferrably property-based. lol.
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spec :: Spec
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spec = do
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it "should infer `id 3` :: Int" $
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let g = [ ("id", "a" :-> "a") ]
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in infer g [coreExpr|id 3|] `shouldBe` Right TyInt
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it "should not infer `id 3` when `id` is specialised to `a -> a`" $
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let g = [ ("id", ("a" :-> "a") :-> "a" :-> "a") ]
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in infer g [coreExpr|id 3|] `shouldSatisfy` isUntypedVariableErr
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isUntypedVariableErr :: HMError a -> Bool
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isUntypedVariableErr (Left (TyErrCouldNotUnify _ _)) = True
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isUntypedVariableErr _ = False
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