[GHC] #9573: Add warning for invalid digits in integer literals

[GHC]

#9573: Add warning for invalid digits in integer literals
-------------------------------------+-------------------------------------
              Reporter:  vlopez      |            Owner:  vlopez
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Compiler    |          Version:  7.9
  (Parser)                           |         Keywords:  parsing, integer,
            Resolution:              |  octal, binary, hexadecimal,
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Difficult (2-5
       Type of failure:              |  days)
  None/Unknown                       |       Blocked By:
             Test Case:              |  Related Tickets:
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------

Comment (by hvr):

 Replying to [comment:4 vlopez]:
 > However, there's at least one test case which would fail.¹

 ...damn, I spent quite a bit of time to come up with that test-case to
 make sure I covered all code-paths and didn't deviate from the octal
 literal's lexing ;-)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9573#comment:5>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler