Constrained method type accepted in Haskell 98 mode

If I understand this paragraph of the GHC manual correctly, the following code should be rejected in Haskell 98 mode:

{-# LANGUAGE Haskell98 #-}

module Main where

class Compare a where
  comp :: Eq a => a -> a -> Bool

However, it compiles fine for me both with 7.4.2 and 7.6.1.

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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