Record typing bug

The following program causes a type error with nhc98:

  module Test where
  type S a = a
  data T a = A { f :: a } | B { f :: S a }

~/scratch > nhc98 test.hs 
/home/simonmar/fp/bin/i386-unknown-linux/nhc98: test: -ne: unary
operator expected
======  Errors after type inference/checking:
Type error (type-variable occurrence check fails)
when binding final type to function at 5:16.

I get the "test: -ne ..." error every time I start nhc98, so it's
probably unrelated.

I'm not quite sure which version of nhc98 I have here:

> nhc98 --version
/home/simonmar/fp/bin/i386-unknown-linux/nhc98: 2.01
  [ config: ix86-Linux/ by [email protected]
on 22 Aug 2002 ]

Cheers,
	Simon