Ruby

After backporting r50409 and r51617, TestSyntax#test_block_after_cond failed.

r51616 should be backported too?

I was implementing this in my Ruby parser and I found a much simpler solution than what you've implemented here: https://github.com/whitequark/parser/commit/113442eff1f9c6f7e7205ec0dac8cb858b3b0fc7

In short, instead of explicitly enumerating all contexts where a label is valid, I only disallow quoted label at EXPR_VALUE using an additional flag. It works just as well. It also would not exhibit the bug with %w during backport.

Might I suggest a simplification to parse.y?

Currently it's a bit flag in parse.y too.