Handle mismatched end when using rescue without begin

[mauro-oto]

Handles cases where mismatched ends happens on methods using
rescue without begin:

unexpected `rescue', expecting `end'

[mauro-oto]

I was just reading #68, and it looks like this is related.. so probably not the best way to handle it, it fixes this case, but might make it confusing for other cases.

@schneems should we scope this to just rescue, or do you prefer I close it for the time being?

[schneems]

Before:

$ dead_end /tmp/scratch.rb

file: /tmp/scratch.rb
simplified:

    ❯ 1  def foo
    ❯ 2    if bar
    ❯ 4    else
    ❯ 6  rescue FooBar
    ❯ 7    nil
    ❯ 8  end

After:

$ exe/dead_end /tmp/scratch.rb

DeadEnd: Unmatched `end` detected

This code has an unmatched `end`. Ensure that all `end` lines
in your code have a matching syntax keyword  (`def`,  `do`, etc.)
and that you don't have any extra `end` lines.

file: /tmp/scratch.rb
simplified:

    ❯ 1  def foo
    ❯ 2    if bar
    ❯ 4    else
    ❯ 6  rescue FooBar
    ❯ 7    nil
    ❯ 8  end

That is improved, as you mention #68 though it causes some somewhat unexpected side effects, using the code from #68:

Before:

file: /tmp/scratch.rb
simplified:

      1  def foo
    ❯ 2    1,2,3,4]
      3  end

After:

DeadEnd: Unmatched `end` detected

This code has an unmatched `end`. Ensure that all `end` lines
in your code have a matching syntax keyword  (`def`,  `do`, etc.)
and that you don't have any extra `end` lines.

file: /tmp/scratch.rb
simplified:

      1  def foo
    ❯ 2    1,2,3,4]
      3  end

Which isn't correct. I'm not totally sure how to move forwards. I think the change is good, the behavior to not parse the error message when there's a backtick in it was more-or-less accidental.

I'm thinking that we merge this, and then consider this new behavior of identifying a missing bracket as a "missing end" as a separate bug.

What do you think?

Then regarding that bug I'm wondering if maybe it's good enough assumption that "unexpected comma expecting end" is an edge case and we can use that to filter or work around it?

[schneems]

Also, I filed some other label issues #84 and #85.