[GHC] #8353: Easy way to defer type errors

[GHC]

#8353: Easy way to defer type errors
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       Reporter:  goldfire          |             Owner:
           Type:  feature request   |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  GHCi              |           Version:  7.6.3
       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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 A number of comments I've heard recently have focused on the joy of
 `-fdefer-type-errors`, especially for newcomers to Haskell. However, in
 GHCi, one has to

 1. be aware that `-fdefer-type-errors` exists
 2. know the `:set ...` syntax to turn it on, and then
 3. is stuck with this setting on until they turn it off

 Instead, I propose new `:load!` and `:reload!` commands (abbreviated to
 `:l!` and `:r!`) which turn on `-fdefer-type-errors` just for that one
 command. When a load or reload fails, the error message could suggest
 these alternate forms.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8353>
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