unused import not always reported

[Simon Marlow]

> How is it possible that an unused import warning is not 
> always emitted?
> 
> Below I get a warning when I recompile everything, but no 
> warning when I 
> only recompile the Main module (that contains the unused import). In 
> fact Main.hi changes.

It could be a bug, but we'll need to reproduce it here to be sure.
Could you send the sources please?

Cheers,
	Simon