[GHC] #10738: Make Exception datatypes into newtypes

[GHC]

#10738: Make Exception datatypes into newtypes
-------------------------------------+-------------------------------------
              Reporter:              |             Owner:
  RyanGlScott                        |
                  Type:  feature     |            Status:  new
  request                            |
              Priority:  normal      |         Milestone:
             Component:              |           Version:  7.10.2
  libraries/base                     |
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
             Test Case:              |        Blocked By:
              Blocking:              |   Related Tickets:  #4961
Differential Revisions:              |
-------------------------------------+-------------------------------------
 Certain instances of `Exception` in `base` are datatypes with only one
 argument:

 {{{#!hs
 data RecUpdError = RecUpdError String
 data RecConError = RecConError String
 data RecSelError = RecSelError String
 data PatternMatchFail = PatternMatchFail String
 data NoMethodError = NoMethodError String
 data AssertionFailed = AssertionFailed String
 }}}

 Why not make these into `newtype`s?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10738>
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