[GHC] #1974: length "foo" doesn't work with -XOverloadedStrings

[GHC]

#1974: length "foo" doesn't work with -XOverloadedStrings
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        Reporter:  ganesh            |                Owner:  (none)
            Type:  feature request   |               Status:  closed
        Priority:  normal            |            Milestone:  ⊥
       Component:  Compiler          |              Version:  6.8.1
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by sjakobi):

 * status:  new => closed
 * resolution:   => fixed


Comment:

 Replying to [comment:9 parcs]:
 > Have you considered changing the instance declaration from
 >
 > {{{
 > instance IsString String where
 > }}}
 >
 > to
 >
 > {{{
 > instance (a ~ Char) => IsString [a] where
 > }}}
 >
 > This new instance will make `length "foo"` happily typecheck, but it
 will also overlap with other `IsString` instances of the form `[T]`.
 (Though I don't think such instances are common in practice.)

 That change with in GHC-8.0 / base-4.9:

 {{{#!hs
 GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
 > length "foo"
 3
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1974#comment:10>
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