Failure in "Invalid bit strings" bit string literal test

[Matthewar]

  Parser tests
    Parser token types constructors
      Bit string constructor
        Invalid bit strings:                                            FAIL
          *** Failed! Falsifiable (after 9 tests):
          Exception thrown while showing test case:
            test/Spec/Parser/Types/Token.hs:(135,17)-(137,41): Non-exhaustive patterns in function findInvalid

          Use --quickcheck-replay=925432 to reproduce.

On commit 567baf1

[Matthewar]

Presumably missing case is when list is empty which has no match, but the list should never be empty.

[Matthewar]

Issue must occur when the list is either empty, or only has valid characters.
Problem found in checkInvalid, there is no state where it is not true, if all characters are valid it eventually checks the empty list which counts as an invalid input as wanted.