[GHC] #5108: Allow unicode sub/superscript symbols in both identifiers and operators

[GHC]

#5108: Allow unicode sub/superscript symbols in both identifiers and operators
-------------------------------------+-------------------------------------
        Reporter:                    |                   Owner:
  mikhail.vorozhtsov                 |                  Status:  infoneeded
            Type:  feature request   |               Milestone:  7.12.1
        Priority:  normal            |                 Version:  7.1
       Component:  Compiler          |                Keywords:  lexer
  (Parser)                           |  unicode
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by thomie):

 {{{
 λ> let ᵤxᵤy = 1
 }}}

 GHC 7.10 follows Unicode standard 7.0, in which `'ᵤ'` (`'\x2b9'`) is in
 the `ModifierLetter` (Lm) general category, so that will no longer
 compile.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5108#comment:16>
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