id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
1311	newtypes of unboxed types disallowed - documentation bug and/or feature request	Isaac Dupree		"Tested in 6.6.1 and today's 6.7 (which claims to be version 6.7.20070418),

{{{newtype FastBool = FastBool Int#}}}

doesn't work. However this is not documented in the unboxed-types documentation in the User's Guide that lists similar restrictions http://www.haskell.org/ghc/docs/latest/html/users_guide/primitives.html

Similarly (maybe), in phantom type arguments, even in GADTs where kind inference could be at work

{{{data Boo a where Boo :: Int# -> Boo Int#}}}

doesn't work.

I tried {{{newtype ( FastBool :: # ) = ...}}} , and {{{data Boo ( a :: # ) where...}}} , which just confused GHC.

Is there a reason that coercions of unlifted types shouldn't work, or is it just unimplemented?  (inspired by looking at GHC's 
compiler/utils/FastTypes.lhs and thinking that using newtypes instead of type synonyms in places like that would improve type-safety)"	feature request	new	low	_|_	Compiler	6.6.1				Unknown/Multiple	Unknown/Multiple		Unknown