Method lookup weirdness

Ruby
1

Hi,

I’m a bit mystified by the following:

Strange

module Foo
extend self
def bar; ‘bar’ end
end

Foo.bar

module Foo
remove_method :bar
end

Foo.bar

=> ‘bar’ # eh?

Normal

module Bar
extend self
def foo; ‘foo’ end
end

module Bar
remove_method :foo
end

Bar.foo

undefined method `foo’ for Bar:Module (NoMethodError)

Broken

$ irb
module Qux
extend self
def bar; ‘bar’ end
end

Qux.bar

module Qux
remove_method :bar
end

GC.start # eats Qux#bar ?

Qux.bar
[BUG] terminated node (0x4057fdd8)
ruby 1.8.4 (2005-12-24) [i486-linux]

The crash happens only in irb in my testing.

What might be causing this? If anyone with more
knowledge of Ruby’s internals could shed
light on this, I’d be grateful.