ghc --make feature request

[Carl R. Witty]

"Simon Marlow" <simonmar@microsoft.com> writes:

> GHC actually has rather sophisticated recompilation checking which
> goes beyond just checking whether the interface changed - it keeps
> version information for each entity exported by a module and only
> recompiles if any of the entities actually used by the module have
> changed (this is described in the user's guide under the section on
> recompilation checking).

I've seen unexpected compiles using ghc --make.  I've got a system
with modules A, B, and C; A depends on B and B depends on C.  I've
seen the following sequence of events:

I change C
ghc --make A compiles C, B, and A
I change A
ghc --make A skips C and compiles B and A

I don't know of any reason why it would have compiled B in the second
case.

If this is not a known bug, I can try to reproduce it and submit a
formal bug report.

Carl Witty