ghc --make and missing interface files

Hello all, I have a file BinaryIO.  This used to import a module
HGetCharHack to work around an annoying problem with ghc5.04 which
meant that hGetChar was blocking unexpectedly.  However I see that
this problem has now been fixed in ghc6 (ta very much, Simon) so I
deleted the files HGetCharHack.*, modified BinaryIO to stop importing
it, and then tried to compile it using ghc --make.  However the thing
fell over, as follows:

> Skipping ... (lots of files) ...
> Skipping UnionFind
>
> Could not find interface file for `HGetCharHack'
> (use -v to see a list of the files searched for)

What I think is happening is that ghc --make is picking up BinaryIO.hi
somehow, discovering that it refers to HGetCharHack, and complaining
when it can't find HGetCharHack.  At any rate, deleting BinaryIO.hi
fixed the problem.

What I think it should do is not look at BinaryIO.hi when BinaryIO.hs
is newer, or at least not be so surprised when an obsolete BinaryIO.hi
refers to non-existent modules.

****

Oh, by the way, I don't think I've said thank you very much for ghc6,
which in general is very good, and mostly works fine, so please take
that as read now.  Alas there isn't a glasgow-haskell-thanks@xxxxxxxxxxx
list, so -bugs will have to do ...