Should insert_after & insert_before clobber at the same insertion point?

[marcandre]

I feel that insert_before and insert_after should be revised in light of #399.

In particular, the following code currently raises clobbering errors:

      @rewriter.
        insert_after(range(5, 1), '>').
        insert_before(range(6, 0), '[').
        insert_after(range(6, 0), ']').
        insert_before(range(6, 1), '<').
        process

I feel that the code above should be allowed without errors. One argument is that the following code is equivalent but does not raise a clobbering error:

      @rewriter.
        replace(range(5, 1), "#{range(5, 1).source}>").
        replace(range(6, 0), "[#{range(6, 0).source}]").
        replace(range(6, 1), "<#{range(6, 1).source}").
        process

The above examples should both produce 'foo ba>[]<r baz.

In short, I'd suggest that there should be no cloberring error as long as there's at most one of each insert done on a non-empty range, and at most one of each done on an empty range (like in the example above).

Let me know if I should provide a PR for this.

[whitequark]

@alexdowad @JoshCheek thoughts?

[alexdowad]

This makes a lot of sense. Thumbs up!