Debugging letrec typechecking

parser-typechecker/src/Unison/ABT.hs

@@ -393,7 +393,7 @@ subtract _ t1s t2s =
 instance (Show1 f, Var v) => Show (Term f v a) where
   -- annotations not shown
   showsPrec p (Term _ _ out) = case out of
-    Var v -> (Text.unpack (Var.shortName v) ++)
+    Var v -> (show v ++)
     Cycle body -> showsPrec p body
     Abs v body -> showParen True $ (Text.unpack (Var.shortName v) ++) . showString ". " . showsPrec p body
     Tm f -> showsPrec1 p f

parser-typechecker/src/Unison/Term.hs

@@ -250,7 +250,7 @@ lam'' vs body = foldr lam body vs
 -- | Smart constructor for let rec blocks. Each binding in the block may
 -- reference any other binding in the block in its body (including itself),
 -- and the output expression may also reference any binding in the block.
-letRec :: Ord v => [(v,Term v)] -> Term v -> Term v
+letRec :: Ord v => [(v, Term' vt v)] -> Term' vt v -> Term' vt v
 letRec [] e = e
 letRec bindings e = ABT.cycle (foldr ABT.abs z (map fst bindings))
   where

parser-typechecker/src/Unison/TypeVar.hs

@@ -13,7 +13,7 @@ underlying (Universal v) = v
 underlying (Existential v) = v
 
 instance Show v => Show (TypeVar v) where
-  show (Universal v) = show v
+  show (Universal v) = "@" ++ show v
   show (Existential v) = "'" ++ show v
 
 instance Var v => Var (TypeVar v) where

parser-typechecker/src/Unison/Typechecker/Components.hs

@@ -6,7 +6,7 @@ import           Data.Maybe
 import           Data.Set (Set)
 import qualified Data.Set as Set
 import qualified Unison.ABT as ABT
-import           Unison.Term (Term)
+import           Unison.Term (Term')
 import qualified Unison.Term as Term
 import           Unison.Var (Var)
 
@@ -63,7 +63,7 @@ components' freeVars bs =
 --
 -- Gets rid of the let rec and replaces it with an ordinary `let`, such
 -- that `id` is suitably generalized.
-minimize :: Var v => Term v -> Maybe (Term v)
+minimize :: Var v => Term' vt v -> Maybe (Term' vt v)
 minimize (Term.LetRecNamed' bs e) = case components bs of
   [_single] -> Nothing
   cs -> Just $ foldr mklet e cs where
@@ -73,5 +73,5 @@ minimize (Term.LetRecNamed' bs e) = case components bs of
     mklet cycle e = Term.letRec cycle e
 minimize _ = Nothing
 
-minimize' :: Var v => Term v -> Term v
+minimize' :: Var v => Term' vt v -> Term' vt v
 minimize' term = fromMaybe term (minimize term)

parser-typechecker/src/Unison/Typechecker/Context.hs

@@ -42,6 +42,7 @@ import qualified Unison.Term as Term
 import qualified Unison.Type as Type
 import           Unison.TypeVar (TypeVar)
 import qualified Unison.TypeVar as TypeVar
+import           Unison.Typechecker.Components (minimize')
 import           Unison.Var (Var)
 import qualified Unison.Var as Var
 -- uncomment for debugging
@@ -67,10 +68,10 @@ data Element v
 
 instance Var v => Show (Element v) where
   show (Var v) = case v of
-    TypeVar.Universal v -> Text.unpack (Var.shortName v)
+    TypeVar.Universal x -> "@" <> show x
-    TypeVar.Existential v -> "'"++Text.unpack (Var.shortName v)
+    TypeVar.Existential x -> "'" ++ show x
   show (Solved v t) = "'"++Text.unpack (Var.shortName v)++" = "++show t
-  show (Ann v t) = Text.unpack (Var.shortName v)++" : "++show t
+  show (Ann v t) = Text.unpack (Var.shortName v) ++ " : " ++ show t
   show (Marker v) = "|"++Text.unpack (Var.shortName v)++"|"
 
 (===) :: Eq v => Element v -> Element v -> Bool
@@ -546,7 +547,9 @@ instantiateR t v = getContext >>= \ctx -> case Type.monotype t >>= solve ctx v o
       setContext $ ctx `append` context [Marker x', Existential x']
       instantiateR (ABT.bind body (Type.existential x')) v
       modifyContext (retract (Marker x'))
-    _ -> fail $ "could not instantiate right " ++ show t
+    _ -> do
+      logContext ("failed: instantiateR " <> show t <> " " <> show v)
+      fail $ "could not instantiate right " ++ show t
 
 withEffects :: [Type v] -> M v a -> M v a
 withEffects abilities' m =
@@ -593,7 +596,7 @@ check e t = getContext >>= \ctx -> scope ("check: " ++ show e ++ ":   " ++ show
         a <- synthesize e; ctx <- getContext
         subtype (apply ctx a) (apply ctx t)
       (as, t') = Type.stripEffect t
-    in withEffects as $ go e t'
+    in withEffects as $ go (minimize' e) t'
   else
     scope ("context: " ++ show ctx) .
     scope ("term: " ++ show e) .
@@ -618,6 +621,7 @@ annotateLetRecBindings letrec = do
   -- annotate each term variable w/ corresponding existential
   -- [marker e1, 'e1, 'e2, ... v1 : 'e1, v2 : 'e2 ...]
   appendContext $ context (Marker e1 : map Existential es ++ zipWith Ann vs (map Type.existential es))
+  logContext "annotating letrec bindings"
   -- check each `bi` against `ei`; sequencing resulting contexts
   Foldable.traverse_ (\(e,(_,binding)) -> check binding (Type.existential e)) (zip es bindings)
   -- compute generalized types `gt1, gt2 ...` for each binding `b1, b2...`;
@@ -632,7 +636,8 @@ annotateLetRecBindings letrec = do
 -- | Synthesize the type of the given term, updating the context in the process.
 -- | Figure 11 from the paper
 synthesize :: Var v => Term v -> M v (Type v)
-synthesize e = scope ("synth: " ++ show e) $ logContext "synthesize" >> go e where
+synthesize e = scope ("synth: " ++ show e) $ go (minimize' e)
+  where
   go :: Var v => Term v -> M v (Type v)
   go (Term.Var' v) = getContext >>= \ctx -> case lookupType ctx v of -- Var
     Nothing -> fail $ "type not known for term var: " ++ Text.unpack (Var.name v)
@@ -838,7 +843,7 @@ synthesizeApp ft arg = scope ("synthesizeApp: " ++ show ft ++ " " ++ show arg) $
     ambientEs <- getAbilities
     o <$ check arg (Type.effect ambientEs i)
   go (Type.Existential' a) = do -- a^App
-    [i,o] <- traverse freshenVar [a, ABT.v' "o"]
+    [i,o] <- traverse freshenVar [ABT.v' "i", ABT.v' "o"]
     let soln = Type.Monotype (Type.existential i `Type.arrow` Type.existential o)
     let ctxMid = context [Existential o, Existential i, Solved a soln]
     modifyContext' $ replace (Existential a) ctxMid

parser-typechecker/src/Unison/Var.hs

@@ -24,7 +24,7 @@ import qualified Data.Set as Set
 --     info attached to `v` values may participate in the `Eq` or `Ord` instances,
 --     it is 'just' metadata.
 --
-class (Eq v, Ord v) => Var v where
+class (Show v, Eq v, Ord v) => Var v where
   named :: Text -> v
   rename :: Text -> v -> v
   name :: v -> Text

parser-typechecker/tests/Unison/Test/Typechecker.hs

@@ -125,6 +125,17 @@ test = scope "typechecker" . tests $
              |r12 : UInt64
              |r12 = (x -> x) 64
              |
+             |id : forall a . a -> a
+             |id x = x
+             |
+             |r13 : (UInt64, Text)
+             |r13 = let
+             |  id = ((x -> x): forall a . a -> a)
+             |  (id 10, id "foo")
+             |
+             |r14 : (forall a . a -> a) -> (UInt64, Text)
+             |r14 id = (id 10, id "foo")
+             |
              |() |]
 
   , checks [r|effect Abort where
@@ -156,7 +167,19 @@ test = scope "typechecker" . tests $
              |bork = u -> 1 +_UInt64 (Abort.Abort ())
              |
              |() |]
-  , checks [r|--State effect
+  , checks [r|--State1 effect
+             |effect State se2 where
+             |  put : ∀ se . se -> {State se} ()
+             |  get : ∀ se . () -> {State se} se
+             |
+             |state woot eff = case eff of
+             |  { State.get () -> k } -> handle state woot in k woot
+             |  { State.put snew -> k } -> handle (state snew) in (k ())
+             |  { a } -> (woot, a)
+             |
+             |()
+             |]
+  , checks [r|--State2 effect
              |effect State se2 where
              |  put : ∀ se . se -> {State se} ()
              |  get : ∀ se . () -> {State se} se
@@ -165,13 +188,13 @@ test = scope "typechecker" . tests $
              |state woot eff = case eff of
              |  { State.get () -> k } -> handle (state woot) in (k woot)
              |  { State.put snew -> k } -> handle (state snew) in (k ())
-             |  { a } -> (woot, a)
              |
-             |ex : (UInt64, UInt64)
+             |()
-             |ex = handle (state 42) in State.get ()
-             |
-             |ex
              |]
+
+             --ex : (UInt64, UInt64)
+             --ex = handle (state 42) in State.get ()
+
   ]
   where c tm typ = scope tm . expect $ check (stripMargin tm) typ
         bombs s = scope s (expect . not . fileTypechecks $ s)