[Truffle] Issue with zsuper calls and optional arguments

[nirvdrum]

Truffle currently will not pass the default values for optional arguments up to super calls. E.g.,

class A
  def m(x, y, z)
    p "A#m(#{x}, #{y}, #{z})"
  end
end

class B < A
  def m(x, y, z = nil)
    super
    p "B#m(#{x}, #{y}, #{z})"
  end
end

B.new.m(5, 4, 3)
B.new.m(5, 4)

Running in MRI we get:

> ruby -v zsuper.rb 
ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-linux]
A#m(5, 4, 3)
B#m(5, 4, 3)
A#m(5, 4, )
B#m(5, 4, )

In JRuby+Truffle, we get:

> bin/jruby -X+T -v zsuper.rb 
jruby 9.0.0.0-SNAPSHOT (2.2.2) 2015-05-14 5ed91b4 Java HotSpot(TM) 64-Bit Server VM 25.45-b02 on 1.8.0_45-b14 +jit [linux-amd64]
A#m(5, 4, 3)
B#m(5, 4, 3)
zsuper.rb:2:in `m': wrong number of arguments (2 for 3) (ArgumentError)
    from zsuper.rb:9:in `m'
    from zsuper.rb:15:in `<main>'

[chrisseaton]

Specs in d265a61

[chrisseaton]

Fixed in various commits. There are still limitations if we have both rest arguments and named args, and probably also with unnamed rest args, but these are now documented in failing specs.