I understand that handling of keyword arguments has changed for mruby 3.1 (to be aligned with CRuby/MRI?), however both Ruby 3.0 and 3.1 handle this code well. At the very least, I think the error message is confusing. What's happening here? On "stable" branch:

puts RUBY_VERSION
class A; def initialize(a: 0); end; end
class B < A; def initialize(a: 0); super(a: a); end; end
class C < B; def initialize(b = 0, a: 0); super(a: a); end; end
p C.new(1)

3.1
trace (most recent call last):
	[3] test.rb:5
	[2] test.rb:5:in new
	[1] test.rb:4:in initialize
test.rb:3:in initialize: can't convert Integer into Proc (TypeError)

Is this related to this recent merge by any chance? 696589c