Implement failure in a less hackish way

elm-format-lib/src/Parse/Helpers.hs

@@ -16,6 +16,7 @@ import qualified Parse.State as State
 import Parse.Comments
 import Parse.IParser
 import Parse.Whitespace
+import qualified Parse.Primitives as EP
 import qualified Reporting.Annotation as A
 import qualified Reporting.Error.Syntax as Syntax
 import qualified Reporting.Region as R
@@ -511,12 +512,18 @@ commentedKeyword elmVersion word parser =
 
 -- ODD COMBINATORS
 
+-- Behaves the same as `Parse.ParsecAdapter.fail` except that the consumed
+-- continuation is called instead of the empty continuation.
 failure :: String -> IParser String
-failure msg = do
-  inp <- getInput
-  setInput ('x':inp)
-  _ <- anyToken
-  fail msg
+failure msg =
+  EP.Parser $ \s _ _ cerr _ ->
+    let
+      (EP.Parser p) = fail msg
+    in
+    -- This looks really unsound, but `p` which was created with `fail` will
+    -- only ever call the empty error continuation (which in this case
+    -- re-routes to the consumed error continuation)
+    p s undefined undefined undefined cerr
 
 
 until :: IParser a -> IParser b -> IParser b

elm-format-lib/src/Parse/ParsecAdapter.hs

@@ -28,8 +28,6 @@ module Parse.ParsecAdapter
   , skipMany
   , runParserT
   , getPosition
-  , getInput
-  , setInput
   , getState
   , updateState
   -- Text.Parsec.Pos
@@ -311,23 +309,6 @@ getPosition =
       return $ newPos sourceName row col
 
 
--- TODO: Figure out why this function is never reached by the test suite.
---
--- This function is needed for elm-format to compile, but leaving it undefined
--- doesn't cause any of the tests to fail.
--- Is there missing coverage in the test suite? Or is this function required by
--- dead code?
---
--- `setInput` is in the same situation.
-getInput :: Parser String
-getInput = undefined
-
-
--- TODO: See `getInput`
-setInput :: String -> Parser ()
-setInput = undefined
-
-
 getState :: Parser State
 getState =
   do  (EP.State _ _ _ _ _ _ _ newline) <- getParserState