[GHC] #12851: Regression: GHC doesn't show filepaths by default anymore

[GHC]

#12851: Regression: GHC doesn't show filepaths by default anymore
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        Reporter:  hvr               |                Owner:
            Type:  bug               |               Status:  new
        Priority:  low               |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:  regression
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by hsyl20):

 Author of the aformentioned patch here. Sorry for the lack of advertising
 of this change.

 1. I didn't want the patch to be too radical, that is why I left the
 extensions "(.hs -> .o)": the paths could be inferred from the module name
 (at least in simple cases) but the extensions may not (.lhs for instance).
 I kept the previous object path display: "nothing"/"interpreted" when the
 target is HscNothing/HscInterpreted.

     Nevertheless I agree that we could totally avoid it. It is already
 what haskell-mode is doing (thanks @gracjan for the comment on
 Phab:D2679#79222). So this doesn't seem to be controversial and I will
 make a patch for this.

 2. Do we need a new flag? Initially SPJ asked for one in #12807 to restore
 the old behaviour and it avoids enabling a too verbose mode. Also we would
 like verbosity levels to be aliases for sets of verbosity flags (see
 #12822).

 3. Flag name: there has been a little bikeshedding about the flag name
 already (see Phab:D2679#77954). Initially I chose "-fshow-module-paths"
 but @nomeata thought "-fshow-source-paths" would be better and I don't
 have a strong opinion on it. I agree that having two flags (for
 source/object paths) would be more correct.

 4. Hiding the object path by default: it doesn't seem controversial. Let's
 do that.

 5. Hiding the the source path by default: I think we should as it is more
 newcomer friendly and in most cases I think we don't care about it (but I
 agree that it depends on your workflow). haskell-mode already hides it.
 Maybe we should have a poll on haskell-cafe or something.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12851#comment:2>
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