Fix NodePattern raising errors on some inputs

[marcandre]

This fixes #5470

Note: the first two commits are not directly related, but make things a bit easier to debug.

[Drenmi]

Thanks @marcandre! 🙇

[Drenmi]

If you're hungry for more, there's a long standing request to add an "any child" matcher. This would be especially helpful when matching on hashes. Consider:

ruby-parse -e '{ foo: 1, bar: 2 }'

(hash
  (pair
    (sym :foo)
    (int 1))
  (pair
    (sym :bar)
    (int 2)))

We may be interested in hashes that have a foo: 1 pair, but the pairs can appear in any order, so we can't reliably match that in a pattern. 🙂

What is needed is a suggested extension to the syntax, and the actual implementation.

[marcandre]

@Drenmi Is there an issue already open for this? Doesn't seem very hard to do...

[Drenmi]

@marcandre I don't think there's an issue, but feel free to open one. 🙂

[marcandre]

@marcandre I don't think there's an issue, but feel free to open one. 🙂

Created #6841