id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
2612	deriving Data.Typeable on phantom newtypes does not report that DeriveDataTypeable is needed	guest		"newtype Foo x = Foo deriving (Typeable)

reports the rather cryptic error message:
    Can't make a derived instance of `Typeable (Foo x)'
      (even with cunning newtype deriving:)
    In the newtype declaration for `Foo'

When newtype is replaced with data, this much more useful error message is given:
    Can't make a derived instance of `Typeable (Foo x)'
      (You need -XDeriveDataTypeable to derive an instance for this class)
    In the data type declaration for `Foo'
"	bug	closed	normal		Compiler	6.9	duplicate		tom.davie@…	MacOS X	x86		Unknown