Fix inverted logic

Author: elopez

lib/Echidna/SourceAnalysis/Slither.hs

@@ -185,4 +185,5 @@ emptySlitherInfo = SlitherInfo mempty mempty mempty mempty mempty [] [] []
 
 isEmptySlitherInfo :: Maybe SlitherInfo -> Bool
 isEmptySlitherInfo (Just (SlitherInfo _ _ _ _ _ [] [] [])) = True
+isEmptySlitherInfo Nothing = True
 isEmptySlitherInfo _ = False

lib/Echidna/UI.hs

@@ -127,7 +127,7 @@ ui vm dict initialCorpus cliSelectedContract = do
           , timeStarted = now
           , timeStopped = Nothing
           , now = now
-          , slitherSucceeded = isEmptySlitherInfo env.slitherInfo
+          , slitherSucceeded = not $ isEmptySlitherInfo env.slitherInfo
           , fetchedContracts = mempty
           , fetchedSlots = mempty
           , fetchedDialog = B.dialog (Just $ str " Fetched contracts/slots ") Nothing 80

lib/Echidna/UI/Widgets.hs

@@ -228,8 +228,8 @@ slitherWidget
   :: Bool
   -> Widget Name
 slitherWidget slitherSucceeded = if slitherSucceeded
-  then alert (str "No Slither in use")
-  else success (str "Slither succeeded")
+  then success (str "Slither succeeded")
+  else alert (str "No Slither in use!")
 
 outOf :: Int -> Int -> Widget n
 outOf n m =