#2677: Detection of TF instance conflict depends on instance order
-------------------------------------+--------------------------------------
Reporter: reinerp | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler (Type checker)
Version: 6.9 | Severity: normal
Keywords: TF instance conflict | Testcase:
Architecture: Unknown/Multiple | Os: Unknown/Multiple
-------------------------------------+--------------------------------------
With 6.10 RC1, the following code compiles without complaint:
{{{
{-# OPTIONS -fglasgow-exts #-}
module OverlapTest where
type family A x
type instance A a = Bool
type instance A Int = Char
}}}
even though the overlapping instances "A a" and "A Int" conflict.
Reordering the instances to
{{{
{-# OPTIONS -fglasgow-exts #-}
module OverlapTest where
type family A x
type instance A Int = Char
type instance A a = Bool
}}}
correctly doesn't compile, complaining about conflicting instances.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2677>
GHC <http://www.haskell.org/ghc/>
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