[GHC] #11256: ghc --make reports bad import errors too eagerly

[GHC]

#11256: ghc --make reports bad import errors too eagerly
-------------------------------------+-------------------------------------
        Reporter:  ezyang            |                Owner:  ezyang
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by ezyang):

 With the fix, three test cases see a diff like the following:

 {{{
 -Q.hs:3:8:
 -    Could not find module ‘Data.Set’
 -    It is a member of the hidden package
 ‘containers-<VERSION>@containers-<VERSION
 >’.
 +Q.hs:3:1:
 +    Failed to load interface for ‘Data.Set’
 +    It is a member of the hidden package ‘containers-<VERSION>’.
      Perhaps you need to add ‘containers’ to the build-depends in your
 .cabal file.
      Use -v to see a list of the files searched for.
 }}}

 Arguably, "Could not find module" is a better error message; however, this
 is indeed the message `-c` gives when it can't find the module, so surely
 it can't be that bad?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11256#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler