id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
2937	source file that compiled fine fails to recompile after touching it (yes, another one)	rwbarton	simonpj	"I'm using the development snapshot `ghc-6.11.20090107` and ran into a bug very similar to #2888, but I think it is different because I could not reproduce that bug in my version.

The setup is very similar: File `A.hs` contains
{{{
{-# LANGUAGE TypeFamilies #-}
module A where
class Foo a where
  data Bar a :: * -> *
}}}
and file `B.hs` contains
{{{
{-# LANGUAGE TypeFamilies #-}
module B where
import A
instance Foo Int where
  data Bar Int x where
    Baz :: Bar Int String
}}}
Then:
{{{
rwbarton@functor:/tmp/a$ ghc --make B
[1 of 2] Compiling A                ( A.hs, A.o )
[2 of 2] Compiling B                ( B.hs, B.o )
rwbarton@functor:/tmp/a$ touch B.hs
rwbarton@functor:/tmp/a$ ghc --make B
[2 of 2] Compiling B                ( B.hs, B.o )

B.hs:8:2:
    Arguments that do not correspond to a class parameter must be variables
    Instead of a variable, found Int
    In the associated type instance for `Bar'
    In the instance declaration for `Foo Int'
}}}"	bug	closed	normal	6.10.2	Compiler	6.11	fixed			Unknown/Multiple	Unknown/Multiple		Unknown	tc245