In general, my approach was to try to eliminate each unused parameter
using Eclipse's "Change Method Signature" refactoring. That did not
always succeed: a parameter may be unused in some base class method,
but then be used in subclass's override of that method. In cases
where refactoring to eliminate a parameter failed, I instead annotated
the parameter with '@SuppressWarnings("unused")' to silence the
warning.
Note: this group of changes creates a significant risk of
incompatibility for third-party WALA code. Some removed parameters
change externally-visible APIs. Furthermore, these changes do not
necessarily lead to Java compilation errors. For example, suppose
third-party code subclasses a WALA class or interface, overrides a
method, but does not annotate that method as @Override. Removing a
parameter means that the third-party method no longer overrides. This
can quietly change code behavior without compile-time errors or
warnings. This is exactly why one should use @Override wherever
possible, but we cannot guarantee that third-party WALA users have
done that.
If a method is private, there's no risk that a subclass elsewhere
might be overriding it and depending on dynamic dispatch to choose the
right implementation. So all of these private methods can safely be
declared static without risk of regression in either WALA code or
unseen third-party code.
Removing an unused field sometimes means removing constructor code
that used to initialize that field. Removing that initialization code
sometimes leaves whole constructor arguments unused. Removing those
unused arguments can leave us with unused code to compute those
arguments in constructors' callers, and so on. This commit tries to
clean all of this up, working backward from the unused fields that an
earlier commit already removed. Hopefully I have avoided removing
upstream code that had other important side effects, but it wouldn't
hurt for a WALA expert to review this change carefully.
Note: some of these methods are decidedly nontrivial. Perhaps they
should not actually be removed? If any should be kept around, please
identify them to me. I'll revise this change to retain those methods
and simply annotate them as needed to suppress Eclipse's warning.
Julian Dolby
Ben Liblit
Julian Dolby
Juergen Graf
Manu Sridharan