19f39f8 · elk · git.iko.soy

git.iko.soy/elk

Avoid cascading errors

When a constraint fails, rather than propagating some bad type through, just assume the type is “anything”. This means the user will get the root issue, but not a bunch of stuff that comes from that. Once it is fixed, they will see any subsequent errors, if there are any.

commit19f39f86ebebe5a8332a2cfdfbf99baa07312f75 authorEvan Czaplicki <info@elm-lang.org> dateThu 9 Jul 2015, 20:18 (11 years ago) parent8972f1e

2 files changed+42−23

compare with master

unifiedsplit

src/Type/Type.hs+16−9 src/Type/Unify.hs+26−14

src/Type/Type.hs+16−9

@@ -92,6 +92,7 @@ data Flex

9292 | Flexible

9393 | Constant

9494 | Is SuperType

95+ | Error

9596 deriving (Eq)

9697

9798data SuperType

@@ -152,15 +153,21 @@ namedVar flex name = UF.fresh $ Descriptor

152153

153154

154155variable :: Flex -> IO Variable

155−variable flex = UF.fresh $ Descriptor

156− { structure = Nothing

157− , rank = noRank

158− , flex = flex

159− , name = Nothing

160− , copy = Nothing

161− , mark = noMark

162− , alias = Nothing

163− }

156+variable flex =

157+ UF.fresh (descriptor flex)

158+

159+

160+descriptor :: Flex -> Descriptor

161+descriptor flex =

162+ Descriptor

163+ { structure = Nothing

164+ , rank = noRank

165+ , flex = flex

166+ , name = Nothing

167+ , copy = Nothing

168+ , mark = noMark

169+ , alias = Nothing

170+ }

164171

165172

166173-- CONSTRAINT HELPERS

src/Type/Unify.hs+26−14

@@ -53,6 +53,9 @@ typeError

5353typeError leftType rightType note =

5454 do leftSrcType <- liftIO (toSrcType leftType)

5555 rightSrcType <- liftIO (toSrcType rightType)

56+ liftIO $ do

57+ UF.setDescriptor leftType (Type.descriptor Error)

58+ UF.setDescriptor rightType (Type.descriptor Error)

5659 throwError (RawMismatch (leftSrcType, rightSrcType, note))

5760

5861

@@ -118,8 +121,11 @@ actuallyUnify variable1 variable2 = do

118121

119122 unifyNumber svar (Var.Canonical home name) =

120123 case home of

121− Var.BuiltIn | name `elem` ["Int","Float"] -> flexAndUnify svar

122− Var.Local | List.isPrefixOf "number" name -> flexAndUnify svar

124+ Var.BuiltIn | name `elem` ["Int","Float"] ->

125+ flexAndUnify svar

126+

127+ Var.Local | List.isPrefixOf "number" name ->

128+ flexAndUnify svar

123129 _ ->

124130 typeError variable1 variable2 Nothing

125131

@@ -134,9 +140,12 @@ actuallyUnify variable1 variable2 = do

134140

135141 unifyComparable v (Var.Canonical home name) =

136142 case home of

137− Var.BuiltIn | name `elem` ["Int","Float","Char","String"] -> flexAndUnify v

138− Var.Local | List.isPrefixOf "comparable" name -> flexAndUnify v

139− _ -> comparableError Nothing

143+ Var.BuiltIn | name `elem` ["Int","Float","Char","String"] ->

144+ flexAndUnify v

145+ Var.Local | List.isPrefixOf "comparable" name ->

146+ flexAndUnify v

147+ _ ->

148+ comparableError Nothing

140149

141150 unifyComparableStructure varSuper varFlex =

142151 do struct <- liftIO $ collectApps varFlex

@@ -148,11 +157,11 @@ actuallyUnify variable1 variable2 = do

148157 do flexAndUnify varSuper

149158 unifyHelp v =<< liftIO (variable $ Is Comparable)

150159

151− Tuple vs

152− | length vs > 6 ->

160+ Tuple vs ->

161+ if length vs > 6 then

153162 comparableError $ Just $

154163 "Furthermore, it cannot be a tuple with more than 6 elements."

155− | otherwise ->

164+ else

156165 do flexAndUnify varSuper

157166 cmpVars <- liftIO $ forM [1..length vs] $ \_ -> variable (Is Comparable)

158167 zipWithM_ unifyHelp vs cmpVars

@@ -194,14 +203,17 @@ actuallyUnify variable1 variable2 = do

194203 _ -> typeError variable1 variable2 Nothing

195204

196205 case (structure desc1, structure desc2) of

197− (Nothing, Nothing) | flex desc1 == Flexible && flex desc1 == Flexible ->

198− merge

206+ (Nothing, Nothing)

207+ | flex desc1 == Flexible && flex desc1 == Flexible ->

208+ merge

199209

200− (Nothing, _) | flex desc1 == Flexible ->

201− merge2

210+ (Nothing, _)

211+ | flex desc1 == Flexible -> merge2

212+ | flex desc1 == Error -> return ()

202213

203− (_, Nothing) | flex desc2 == Flexible ->

204− merge1

214+ (_, Nothing)

215+ | flex desc2 == Flexible -> merge1

216+ | flex desc2 == Error -> return ()

205217

206218 (Just (Var1 v), _) ->

207219 unifyHelp v variable2