id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
4841	TypeSynonymInstances allow some flexible instances	benmachine		"The docs for !TypeSynonymInstances say:

  As always, using a type synonym is just shorthand for writing the RHS of the type synonym definition.

However, there are instances that can be defined with ''only'' !TypeSynonymInstances enabled that cannot be defined without it. The following compiles:

{{{
{-# LANGUAGE TypeSynonymInstances #-}
instance Bounded String where
  minBound = """"
  maxBound = maxBound : maxBound
}}}

even though the same with `[Char]` does not."	bug	closed	normal		Compiler	7.0.1	fixed			Unknown/Multiple	Unknown/Multiple	GHC accepts invalid program