[GHC] #3: DiffArray should be instance of Show

[GHC]

#3: DiffArray should be instance of Show
--------------------------------+--------------------
       Reporter:  magunter      |      Owner:  nobody
           Type:  bug           |     Status:  closed
       Priority:  normal        |  Milestone:
      Component:  hslibs/lang   |    Version:  5.0
     Resolution:  Fixed         |   Keywords:
Type of failure:  None/Unknown  |
--------------------------------+--------------------
Changes (by Ben Gamari <ben@…>):

 * failure:   => None/Unknown


Comment:

 In [changeset:"83ee930fdd125d74939307ed3fa1bf6a2ba7fb36/ghc"
 83ee930f/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="83ee930fdd125d74939307ed3fa1bf6a2ba7fb36"
 fix a memory leak in osNumaMask

 got an error when using asan:
 ```
 ==1866689==ERROR: LeakSanitizer: detected memory leaks

 Direct leak of 16 byte(s) in 1 object(s) allocated from:
     #0 0x10640568 in malloc ??:?
     #1 0x154d867e in numa_bitmask_alloc .../numactl-2.0.8/libnuma_nosymve
 r.c:204
     #2 0x154d867e in numa_allocate_nodemask
 .../numactl-2.0.8/libnuma_nosymve r.c:724
     #3 0x154d867e in numa_get_mems_allowed
 .../numactl-2.0.8/libnuma_nosymve r.c:1141
     #4 0x10b54a45 in osNumaMask ...ghc-8.0.2/rts/posix/OSMem.c:59 8
 ```

 Test Plan: compile, validate

 Reviewers: simonmar, niteria, austin, bgamari, erikd

 Reviewed By: bgamari

 Subscribers: rwbarton, thomie

 Differential Revision: https://phabricator.haskell.org/D3537
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3#comment:4>
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