[GHC] #11573: Inferred CallStacks expose implicit parameter

[GHC]

#11573: Inferred CallStacks expose implicit parameter
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:  gridaphobe
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  8.0.1-rc2
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11383            |  Differential Rev(s):  Phab:D1911,
       Wiki Page:                    |  Phab:D1912
-------------------------------------+-------------------------------------
Changes (by gridaphobe):

 * differential:  Phab:D1911 => Phab:D1911, Phab:D1912
 * related:   => #11383


Comment:

 > Here we infer foo :: [a] -> a, without a HasCallStack constraint.
 Correct?

 That's incorrect as of the reworked solver, but as you've seen D1912 is
 going to put the original "don't infer top-level call-stacks" behavior
 back in place.

 > - The user manual was updated to be a more complete and accurate spec
 > - It referred to the wiki page

 Sure, I didn't realize we linked to the wiki from the manual.

 > - The wiki page was updated to reflect reality

 I've been treating the wiki page as append-only, so I'll add a section
 that explains the final design.

 > I think that a let binding in GHCi should have the same status as a top-
 level binding in a module

 I agree, and D1912 does treat them as top-level.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11573#comment:5>
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