I cannot recreate this:

$ irb
irb(main):001:0> *a = 1
=> 1
irb(main):002:0> a
=> [1]
irb(main):003:0>    # Ctrl-D pressed here

Just returns to prompt.

ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux]

Installed with rvm on Arch Linux x86_64.