[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     |           Status:  new
  request                            |        Milestone:
              Priority:  normal      |          Version:  7.6.3
             Component:  GHCi        |         Keywords:  newcomer
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:              |  Related Tickets:
  None/Unknown                       |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Changes (by goldfire):

 * keywords:   => newcomer


Comment:

 Though I originally encountered my desire for this feature in a teaching
 setting, it happens in my own work, too.

 Say I have a big file with lots of definitions. Somewhere, there is a type
 error. To fix the type error, I need to check the types of other
 definitions in my file. But, I can't use GHCi to query my definitions,
 because the file has a type error. Urgh. So, today, I have to enable
 `-fdefer-type-errors`, load the file, see my type ''warnings'', and then
 query the definitions I need to fix everything up. A big annoyance of this
 workflow is that, now, `-fdefer-type-errors` is on and stays on until I
 reboot GHCi.

 None of this is the end of anybody's world, but I just think it would be
 easier for everyone -- particularly newcomers to Haskell -- if there were
 just a way to "force" loading, by enabling deferred type errors for one
 compilation. That's the proposal here.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8353#comment:2>
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