[GHC] #15115: `Numeric.showEFloat` does not honor precision with 0 digits

[GHC]

#15115: `Numeric.showEFloat` does not honor precision with 0 digits
-------------------------------------+-------------------------------------
        Reporter:  guibou            |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.6.1
       Component:  libraries/base    |              Version:  8.4.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  libraries/base/tests/Numeric/num008
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4665
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"9039f847a568ac69436d449b9fe090ecd03b9e06/ghc"
 9039f847/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="9039f847a568ac69436d449b9fe090ecd03b9e06"
 base: Fix handling of showEFloat (Just 0)

 Previously `showEFloat (Just 0) pi ""` would produce `3.0e0`. Of
 course, this
 blatantly disrespects the user's request to print with zero digits of
 precision.
 Fix this.

 This is tested by base's `num008` testcase.

 Test Plan: Validate

 Reviewers: hvr

 Subscribers: rwbarton, thomie, carter

 GHC Trac Issues: #15115

 Differential Revision: https://phabricator.haskell.org/D4665
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15115#comment:3>
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