id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
5853	Out-of-memory crash when using RULES and type families	porges	simonpj	"GHC(i) 7.4.1 crashes with an OOM error on the following code:

{{{
{-# LANGUAGE NoImplicitPrelude, TypeFamilies #-}

import Prelude (undefined,Bool(..),Show(..),(.))

type family Elem f :: *
type family Subst f b :: *

class (Subst fa (Elem fa) ~ fa) => F fa where
	(<$>) :: (Elem fa ~ a, Elem fb ~ b,
	          Subst fa b ~ fb, Subst fb a ~ fa) =>
			 (a -> b) -> (fa -> fb)

{-# RULES
""map/map"" forall f g xs. f <$> (g <$> xs) = (f.g) <$> xs
	#-}
}}}"	bug	closed	high	7.4.2	Compiler	7.4.1	fixed		dimitris@…	Windows	x86_64 (amd64)	Compile-time crash	Unknown	typecheck/should_fail/T5853