IronRuby Rake and -X:PrivateBinding

Question

I'm trying to setup a Rake script to run all my IronRuby rspec tests. The tests need to have access to internal constructors and methods. IronRuby supports this with the -X:PrivateBinding switch on ir.exe.

So, for example, if my test is called some_tests.rb, the following command works:

ir -X:PrivateBinding -S spec some_tests.rb

However, when I try to run rake that way it bombs out.

To repo, follow these steps:

Write a rakefile like the following:

task :test do
  puts "TEST PASSED"
end

Running this command will succeed:

ir -S rake test

Running this command will fail:

ir -X:PrivateBinding -S rake test

with the following error: C:/IronRuby 1.1/lib/ironruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1275: syntax error, unexpected `.'

I'm running IronRuby 1.1.0.0 on .NET 4.0.30319.1 with rake 0.8.7.