If searching for a Tree-based match, the target may use extra parenthesis for aesthetical reasons, which do not influence the actual semantics. 
The CopyFinder should (optionally) support such situation and match a tree that differs only in meaningless parenthesis.

Likewise for commutative operations, variable on either side should match.

Some operations are not strictly commutative, but can be flipped provided that operator changes, i.e. x >= y is equivalent to y <= x. 

In the case of integer literals (or compile-time constant references) the above is also requivalent to x > (y - 1) etc.

Allowing such equivalent matches would allow to code less triggers for hints and potentially find more duplicates of tree fragments.