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  • Glasgow Haskell Compiler
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  • #2677
Closed
Open
Created Oct 09, 2008 by reinerp@trac-reinerp

Detection of TF instance conflict depends on instance order

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.

Trac metadata
Trac field Value
Version 6.9
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system Unknown/Multiple
Architecture Unknown/Multiple
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