Re: [GHC] #10341: hs-boot files can have bogus declarations if they're not exported

22 Apr 2015

      #10341: hs-boot files can have bogus declarations if they're not exported
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        Reporter:  ezyang            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  low               |               Milestone:
       Component:  Compiler (Type    |                 Version:  7.11
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  GHC accepts       |               Test Case:
  invalid program                    |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:                    |
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Description changed by simonpj:

Old description:
...
Consider:
{{{
-- A.hs-boot
module A(foo) where
data A  = AC { bar :: Int } | CC
-- B.hs
module B where
import {-# SOURCE #-} A
-- A.hs
module A(foo) where
import B
data A = AC { foo :: Int } | BC
}}}
GHC won't complain that `A` is incompatibly defined, since it's not
exported.
Seems relatively harmless though.
New description:

 Consider:

 {{{
 -- A.hs-boot
 module A(foo) where
   foo :: A -> Int
   data A  = AC { bar :: Int } | CC
    -- NB: A is not exported

 -- B.hs
 module B where
   import {-# SOURCE #-} A

 -- A.hs
 module A(foo) where
   import B
   data A = AC { foo :: Int } | BC
 }}}

 GHC won't complain that `A` is incompatibly defined, since it's not
 exported.

 Seems relatively harmless though.

--

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10341#comment:1
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