[ruby/prism] Implicit rest nodes

Fundamentally, `foo { |bar,| }` is different from `foo { |bar, *| }`
because of arity checks. This PR introduces a new node to handle
that, `ImplicitRestNode`, which goes in the `rest` slot of parameter
nodes instead of `RestParameterNode` instances.

This is also used in a couple of other places, namely:

* pattern matching: `foo in [bar,]`
* multi target: `for foo, in bar do end`
* multi write: `foo, = bar`

Now the only splat nodes with a `NULL` value are when you're
forwarding, as in: `def foo(*) = bar(*)`.

https://github.com/ruby/prism/commit/dba2a3b652

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/prism/debug.rb b/lib/prism/debug.rb
index d0469adc9a..adbc402f32 100644
--- a/lib/prism/debug.rb
+++ b/lib/prism/debug.rb
@@ -121,7 +121,7 @@ module Prism
                 end
               end,
               *params.optionals.map(&:name),
-              *((params.rest.name || :*) if params.rest && params.rest.operator != ","),
+              *((params.rest.name || :*) if params.rest && !params.rest.is_a?(ImplicitRestNode)),
               *params.posts.map do |post|
                 if post.is_a?(RequiredParameterNode)
                   post.name