#1465: Type errors due to different package versions are a bit cryptic
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Reporter: guest | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 6.8
Component: Compiler (Type checker) | Version: 6.6.1
Severity: normal | Resolution:
Keywords: | Difficulty: Easy (1 hr)
Os: Unknown | Testcase: tcfail182
Architecture: Unknown |
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Changes (by simonpj):
* testcase: => tcfail182
Comment:
Excellent suggestion. I've arranged to print more info if the two types
have the same occurrence name, since some confusion may then occur. For
example:
{{{
module Foo where
import qualified Prelude
import Prelude hiding( Maybe )
data Maybe a = Foo
f :: Prelude.Maybe a -> Int
f Foo = 3
}}}
now produces the error:
{{{
Foo.hs:11:2:
Couldn't match expected type `Prelude.Maybe a'
against inferred type `Maybe a1'
`Prelude.Maybe' is defined in module `Data.Maybe' from package
`base'
`Maybe' is defined in this module
In the pattern: Foo
In the definition of `f': f Foo = 3
}}}
Can you check that your use-case is also improved, and if so close the
bug?
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1465>
GHC <http://www.haskell.org/ghc/>
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