[GHC] #11047: Provide call stacks in GHCi

[GHC]

#11047: Provide call stacks in GHCi
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        Reporter:  simonmar          |                Owner:  simonmar
            Type:  task              |               Status:  new
        Priority:  high              |            Milestone:  8.0.1
       Component:  GHCi              |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #545, #4837       |  Differential Rev(s):  Phab:D1407
       Wiki Page:                    |
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Comment (by Simon Marlow <marlowsd@…>):

 In [changeset:"8988be8561ce0857f3befd6ab3b6c29060685c0a/ghc" 8988be8/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="8988be8561ce0857f3befd6ab3b6c29060685c0a"
 Make 'error' include the CCS call stack when profiled

 Summary:
 The idea here is that this gives a more detailed stack trace in two
 cases:

 1. With `-prof` and `-fprof-auto`
 2. In GHCi (see #11047)

 Example, with an error inserted in nofib/shootout/binary-trees:

 ```
 $ ./Main 3
 Main: z
 CallStack (from ImplicitParams):
   error, called at Main.hs:67:29 in main:Main
 CallStack (from -prof):
   Main.check' (Main.hs:(67,1)-(68,82))
   Main.check (Main.hs:63:1-21)
   Main.stretch (Main.hs:32:35-57)
   Main.main.c (Main.hs:32:9-57)
   Main.main (Main.hs:(27,1)-(43,42))
   Main.CAF (<entire-module>)
 ```

 This doesn't quite obsolete +RTS -xc, which also attempts to display
 more information in the case when the error is in a CAF, but I'm
 exploring other solutions to that.

 Includes submodule updates.

 Test Plan: validate

 Reviewers: simonpj, ezyang, gridaphobe, bgamari, hvr, austin

 Reviewed By: bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D1426
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11047#comment:10>
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