Issue #9931 has been reported by Jesse Adkins.

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Bug #9931: irb: Really weird behavior for x = "#{x\"}" (ex: irb(main:009:-4))
https://bugs.ruby-lang.org/issues/9931

* Author: Jesse Adkins
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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# Our journey starts off rather simple:
irb(main):001:0> x = "#{x}"
=> ""
# Okay, makes sense.
irb(main):002:0> x = "#{x\"}"
irb(main):003:0" 
# Hmm...Still in a string? That's weird.
irb(main):003:0" "
irb(main):004:0> 
# Things seem back to normal but...
irb(main):004:0> x
# Nothing? But x is defined!
irb(main):005:0> 
# Nothing? Hmm...
irb(main):005:0> end
irb(main):006:-1> end
# Uhh...I don't think that's supposed to do that.
irb(main):007:-2> end
irb(main):008:-3> end
irb(main):009:-4> 
# ...I'm afraid to go deeper.
# Get me out of here!
irb(main):009:-4> quit
irb(main):010:-4> 
# O.O
irb(main):010:-4> ^C
irb(main):010:0> 
# ...Can I go now?
irb(main):010:0> quit
# Success!

# Additionally, if I put this in a file:
x = "#{x\"}"

# I get two syntax errors (ruby 1.9.3):
test.rb:1: syntax error, unexpected $undefined, expecting '}'
x = "#{x\"}"
         ^
test.rb:1: syntax error, unexpected $end, expecting '}'
x = "#{x\"}"
            ^




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