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Fix problem with variable shadowing when instantiating aliased types

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This commit is contained in:
Evan Czaplicki 2013-08-08 15:45:22 -07:00
parent c70d59fdf9
commit 143547e766
1 changed files with 28 additions and 28 deletions
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56
compiler/Type/Environment.hs
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@ -122,40 +122,40 @@ instantiator env sourceType = go sourceType
Src.Var x -> do
(dict, aliases) <- State.get
case Map.lookup x dict of
Just var -> return (VarN var)
Nothing ->
case Map.lookup x aliases of
Just t -> return t
Nothing ->
do var <- State.liftIO $ namedVar flex x
State.put (Map.insert x var dict, aliases)
return (VarN var)
where
flex | "number" `isPrefixOf` x = Is Number
| "comparable" `isPrefixOf` x = Is Comparable
| "appendable" `isPrefixOf` x = Is Appendable
| otherwise = Flexible
case (Map.lookup x dict, Map.lookup x aliases) of
(_, Just t) -> return t
(Just v, _) -> return (VarN v)
_ ->
do var <- State.liftIO $ namedVar flex x
State.put (Map.insert x var dict, aliases)
return (VarN var)
where
flex | "number" `isPrefixOf` x = Is Number
| "comparable" `isPrefixOf` x = Is Comparable
| "appendable" `isPrefixOf` x = Is Appendable
| otherwise = Flexible
Src.Data "String" [] ->
return (get env types "_List" <| get env types "Char")
Src.Data name ts -> do
ts' <- mapM go ts
case Map.lookup name (types env) of
Just t -> return $ foldl (<|) t ts'
Nothing ->
case Map.lookup name (aliases env) of
Nothing -> error $ "\nCould not find type constructor '" ++ name ++ "' while checking types."
Just (tvars, t) ->
let tvarLen = length tvars
msg = "\nType alias '" ++ name ++ "' expects " ++ show tvarLen ++
" type argument" ++ (if tvarLen == 1 then "" else "s") ++
" but was given " ++ show (length ts')
in if length ts' /= length tvars then error msg else
do (dict, aliases) <- State.get
State.put (dict, Map.union aliases . Map.fromList $ zip tvars ts')
go t
case (Map.lookup name (types env), Map.lookup name (aliases env)) of
(Just t, _) -> return $ foldl (<|) t ts'
(_, Just (tvars, t)) ->
let tvarLen = length tvars
msg = "\nType alias '" ++ name ++ "' expects " ++ show tvarLen ++
" type argument" ++ (if tvarLen == 1 then "" else "s") ++
" but was given " ++ show (length ts')
in if length ts' /= length tvars then error msg else
do (dict, aliases) <- State.get
let aliases' = Map.union (Map.fromList $ zip tvars ts') aliases
State.put (dict, aliases')
t' <- go t
State.put (dict, aliases)
return t'
_ -> error $ "\nCould not find type constructor '" ++
name ++ "' while checking types."
Src.EmptyRecord -> return (TermN EmptyRecord1)