[GHC] #8051: GHCi: confusing `:set +m`/`:{` interaction & wrong line-numbers in multi-line input

[GHC]

#8051: GHCi: confusing `:set +m`/`:{` interaction & wrong line-numbers in multi-
line input
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        Reporter:  hvr               |            Owner:
            Type:  bug               |           Status:  patch
        Priority:  highest           |        Milestone:  7.8.1
       Component:  GHCi              |          Version:  7.7
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by Herbert Valerio Riedel <hvr@…>):

 In [changeset:43111a0b58f5b2b4cf77b4119bef7b5f3b69d0b3/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="43111a0b58f5b2b4cf77b4119bef7b5f3b69d0b3"
 GHCi: Fix multi-line input line/column-number refs

 This commit addresses #8051 by fixing

  - Incorrect column indices reported in error messages for
    single-line and multi-line input,

  - incorrect line numbers reported in error messages for
    expressions entered in multi-line input, and

  - inhibiting the confusing interaction between `:{` and `:set +m`
    causing the triggering of implicit multi-line continuation
    mode right after `:}` terminates the multi-line entry block.
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8051#comment:4>
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