[GHC] #9947: Unicode «other number» characters not consistently accepted in identifiers

[GHC]

#9947: Unicode «other number» characters not consistently accepted in identifiers
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              Reporter:  zardoz      |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.8.4
  (Parser)                           |  Operating System:  Unknown/Multiple
              Keywords:              |   Type of failure:  None/Unknown
          Architecture:              |        Blocked By:
  Unknown/Multiple                   |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 I’ve noticed that some characters classified as numeric by the Unicode
 standard will currently generate a lexical error. E.g., characters from
 the «enclosed alphanumerics» block don’t work, such as ① (circled digit
 one, U+2460), despite having being of the general Unicode category «other
 number». Usually, «other number» characters are accepted in identifiers.
 E.g., superscripts like «²» work fine.

 This is related to https://ghc.haskell.org/trac/ghc/ticket/5108 , where
 modifier letters (which are also alphanumeric in Unicode) also throw a
 lexical error.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9947>
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