[GHC] #14084: Strange behavior of GHC by writing the types in GHCi

3 Aug 2017

      #14084: Strange behavior of GHC by writing the types in GHCi
-------------------------------------+-------------------------------------
           Reporter:  vanto          |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  GHCi           |           Version:  8.0.2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Incorrect result
  Unknown/Multiple                   |  at runtime
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 * A: you type {{{:set +t}}} then you write {{{1:2}}}, the answer is:\\

 {{{
 Prelude> :set +t
 }}}

 {{{
 Prelude> 1:2

 <interactive>:8:1: error:
     * Non type-variable argument in the constraint: Num [a]
       (Use FlexibleContexts to permit this)
     * When checking the inferred type
         it :: forall a. (Num [a], Num a) => [a]
 }}}
 \\
 * B: you type {{{:t 1:2}}}, the answer is:\\

 {{{
 Prelude> :t 1:2
 1:2 :: (Num [a], Num a) => [a]
 }}}
 \\
 There is an obvious bug. Don't answer me that this behavior is correct,
 please!
 The two answers should be the same.
 Either answer A or answer B.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14084
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