[GHC] #10320: -ddump-to-file should create empty dump files when there was nothing to dump

[GHC]

#10320: -ddump-to-file should create empty dump files when there was nothing to
dump
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        Reporter:  rwbarton          |                Owner:  kaiha
            Type:  bug               |               Status:  merge
        Priority:  low               |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.1
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2015
       Wiki Page:                    |
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Changes (by bgamari):

 * status:  patch => merge
 * milestone:   => 8.0.1


@@ -1,5 +1,5 @@
- For example, I ran with -ddump-rule-firings -ddump-to-file when there were
- no rule firings. GHC should have created an empty foo.dump-rule-firings
- file. (Instead it left the existing foo.dump-rule-firings from a previous
- run intact, which could have been misleading if I didn't already know that
- the most recent run had no rule firings.)
+ For example, I ran with `-ddump-rule-firings -ddump-to-file` when there
+ were no rule firings. GHC should have created an empty `foo.dump-rule-
+ firings` file. (Instead it left the existing `foo.dump-rule-firings` from
+ a previous run intact, which could have been misleading if I didn't
+ already know that the most recent run had no rule firings.)

New description:

 For example, I ran with `-ddump-rule-firings -ddump-to-file` when there
 were no rule firings. GHC should have created an empty `foo.dump-rule-
 firings` file. (Instead it left the existing `foo.dump-rule-firings` from
 a previous run intact, which could have been misleading if I didn't
 already know that the most recent run had no rule firings.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10320#comment:18>
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