[GHC] #8407: Module re-exports at the package level

[GHC]

#8407: Module re-exports at the package level
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        Reporter:  nomeata           |            Owner:  ezyang
            Type:  feature request   |           Status:  new
        Priority:  high              |        Milestone:  7.10.1
       Component:  Package system    |          Version:  7.6.3
      Resolution:                    |         Keywords:  backpack
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by Edward Z. Yang <ezyang@…>):

 In [changeset:"7f5c10864e7c26b90c7ff4ed09d00c8a09aa4349/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="7f5c10864e7c26b90c7ff4ed09d00c8a09aa4349"
 Module reexports, fixing #8407.

 The general approach is to add a new field to the package database,
 reexported-modules, which considered by the module finder as possible
 module declarations.  Unlike declaring stub module files, multiple
 reexports of the same physical package at the same name do not
 result in an ambiguous import.

 Has submodule updates for Cabal and haddock.

 NB: When a reexport renames a module, that renaming is *not* accessible
 from inside the package.  This is not so much a deliberate design choice
 as for implementation expediency (reexport resolution happens only when
 a package is in the package database.)

 TODO: Error handling when there are duplicate reexports/etc is not very
 well tested.

 Signed-off-by: Edward Z. Yang <ezyang at cs.stanford.edu>

 Conflicts:
         compiler/main/HscTypes.lhs
         testsuite/.gitignore
         utils/haddock
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8407#comment:13>
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