[GHC] #10138: hpc does not handle absolute paths correctly

[GHC]

#10138: hpc does not handle absolute paths correctly
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        Reporter:  thomie            |                   Owner:
            Type:  bug               |                  Status:  patch
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Code Coverage     |                 Version:  7.8.4
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:  hpc/T10138
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:  Phab:D703
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Comment (by Thomas Miedema <thomasmiedema@…>):

 In [changeset:"801f4b98fa5198ab7e033949dd84aaae00162993/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="801f4b98fa5198ab7e033949dd84aaae00162993"
 hpc: use System.FilePath.(</>) instead of (++)

 Summary:
 BAD: "." ++ "/" ++ "/absolute/path" == ".//absolute/path"
 GOOD: "." </> "/absolute/path" == "/absolute path"

 Also replace `++ ".ext"` with `<.> "ext"`. Although it doesn't fix any
 bugs in this instance, it might in some other. As a general rule it's
 better not to use (++) on FilePaths.

 Reviewed By: austin, hvr

 Differential Revision: https://phabricator.haskell.org/D703

 GHC Trac Issues: #10138
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10138#comment:2>
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