ignoring contexts (version 6.4.20050304)

Hello,

is it a bug?

When defining

newtype Floating a => Vector a = Vector [a],

version 20050304 accepts e.g.

Vector [True,False], Vector "Hi".

Also making Vector an instance of Functor poses no problems, either by 
deriving or declaring it directly and does not reject

*Vector> fmap even (Vector [1 .. 7])
Vector [False,True,False,True,False,True,False].

Deriving the instance leads to the desired behaviour (rejecting non-Floatings) 
in version 6.2.2.

Is it a bug or intentional?

Cheers,

Daniel Fischer