:: Ord a => [a] -> [a] -package:containers -package:ghc is:exact -package:basement -package:extra -package:Cabal -package:mono-traversable -package:base -package:hedgehog -package:hxt -package:Cabal-syntax package:parsers
Take a parser that may consume input, and on failure, go back to where
we started and fail as if we didn't consume input.