Forbid "leftover" args to interactive commands

src/GHCMod.hs

@@ -110,7 +110,7 @@ legacyInteractiveLoop symdbreq world = do
     res <- flip gcatches interactiveHandlers $ do
       pargs <- maybe (throw $ InvalidCommandLine $ Left cmdArg) return
               $ parseArgsInteractive cmdArg
-      case fst pargs of
+      case pargs of
         CmdFind symbol ->
             lookupSymbol symbol =<< checkDb symdbreq =<< getDb symdbreq
 

src/GHCMod/Options.hs

@@ -37,7 +37,7 @@ parseArgs =
            $$  fullDesc
            <=> header "ghc-mod: Happy Haskell Programming"
 
-parseArgsInteractive :: String -> Maybe (GhcModCommands, [String])
+parseArgsInteractive :: String -> Maybe GhcModCommands
 parseArgsInteractive args =
   getParseResult $ execParserPure (prefs idm) opts $ parseCmdLine args
   where

src/GHCMod/Options/Commands.hs

@@ -179,12 +179,10 @@ commands =
               , text "(See also: https://github.com/kazu-yamamoto/ghc-mod/issues/311)"
               ]
 
-interactiveCommandsSpec :: Parser (GhcModCommands, [String])
+interactiveCommandsSpec :: Parser GhcModCommands
 interactiveCommandsSpec =
-    (,) <$> subparser' icmds <*> leftover
-    where
-      icmds =
-           commands
+    subparser'
+        $  commands
         <> command "map-file"
               $$  info (helper <*> mapArgSpec)
               $$  progDesc "tells ghc-modi to read `file.hs` source from stdin"
@@ -201,7 +199,6 @@ interactiveCommandsSpec =
               $$ progDesc "Exit interactive mode"
         <> command ""
               $$ info (pure CmdQuit) idm
-      leftover = many (strArg "")
 
 strArg :: String -> Parser String
 strArg = argument str . metavar