[Checkers] Framework Change Request

[Mahmood Ali]

> Here's what I opted for instead --
> it's very low impact (in terms of patch size) but also probably less
> effective (in terms of performance boost) than what you've proposed:
>
> - add a cache to AnnotatedTypeFactory that maps Trees to TreePaths
I don't think that such cache is necessary beneficial.  fromExpression  
and getAnnotatedType is called on expression trees almost only once,  
and on class, method, and field trees multiple times but they would be  
calculated only once (due to caching).

I believe that we only need to know the current tree path only.

> I really like your idea better from a design standpoint, though it
> might be a pain to use in some places -- we're not always calling
> getAnnotatedType() in a place where the path is readily available
> (TypeFromTree?), and sometimes even in visitors we call it on a child
> of the current path (e.g., node.getExpression() in visitMemberSelect),
> in which case the path needs to be extended.
Agreed.  I just realized that changing the interface would complicate  
the client code.  It is quite annoying to construct TreePaths all the  
time.

- Mahmood