[plt-scheme] macro question

Hi,

Does the compiler use the types to produce more efficient code? Or are  
the types used just for maintainability purposes?
Also: does the compiler make any kind of type inferencing on user  
defined functions to optimize the compiled code or does it just  
optimize stuff that it already knew about and inline functions/ 
propagate results where it knew it could without analyzing user code?

I would assume it can optimize user code but I'd like to know some  
more details.

s/compiler/JIT/g if it's appropriate.

   - Filipe Cabecinhas