[GHC] #15849: Error message: "Perhaps you need a let in a do block", when there is no do block.

2 Nov 2018

      #15849: Error message: "Perhaps you need a let in a do block", when there is no do
block.
-------------------------------------+-------------------------------------
           Reporter:  cdsmith        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 This code:

 {{{#!haskell
 main = return ()
  foo = return ()
 }}}

 Gives the error message:

 {{{
 parse error on input ‘=’
     Perhaps you need a 'let' in a 'do' block?
     e.g. 'let x = 5' instead of 'x = 5'
 }}}

 But this isn't in a do block.  It would be awesome if GHC checked whether
 there's a do block before giving a suggestion that depends on there being
 a do block.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15849
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