Enumerator combined with reduce using symbols fails

require 'prime'

# FAILS:
p Prime.each(3).reduce(:+)  == 5
p Prime.each(3).reduce(0, :+)  == 5

# Issue seems to be connected with Enumerator
p Enumerator.new{|y| y << 1}.reduce(:+) == 1
p Enumerator.new{|y| y << 1}.reduce(0, :+) == 1


=begin

# WORKS
jruby-1.7.0.preview2 :001 > Enumerator.new{|y| y << 1}.reduce{|sum, n| sum + n}
 => 1 
jruby-1.7.0.preview2 :002 > Enumerator.new{|y| y << 1}.reduce(0){|sum, n| sum + n}
 => 1

# FAILS
jruby-1.7.0.preview2 :003 > Enumerator.new{|y| y << 1}.reduce(:+)
 => nil 
jruby-1.7.0.preview2 :004 > Enumerator.new{|y| y << 1}.reduce(0, :+)
Java::JavaLang::NullPointerException: 
	from org.jruby.RubyNumeric.coerceBody(RubyNumeric.java:447)
	from org.jruby.RubyNumeric.doCoerce(RubyNumeric.java:456)
	from org.jruby.RubyNumeric.coerceBin(RubyNumeric.java:478)
	from org.jruby.RubyFixnum.addOther(RubyFixnum.java:407)
	from org.jruby.RubyFixnum.op_plus(RubyFixnum.java:347)
	from org.jruby.RubyFixnum$INVOKER$i$1$0$op_plus.call(RubyFixnum$INVOKER$i$1$0$op_plus.gen)
	from org.jruby.RubyClass.finvoke(RubyClass.java:749)
	from org.jruby.javasupport.util.RuntimeHelpers.invoke(RuntimeHelpers.java:540)
	from org.jruby.RubyBasicObject.callMethod(RubyBasicObject.java:361)
	from org.jruby.RubyEnumerable$26.call(RubyEnumerable.java:832)
	from org.jruby.runtime.CallBlock.call(CallBlock.java:66)
	from org.jruby.runtime.Block.call(Block.java:89)
	from org.jruby.RubyProc.call(RubyProc.java:271)
	from org.jruby.RubyProc.call19(RubyProc.java:259)
	from org.jruby.RubyYielder.yield(RubyYielder.java:86)
	from org.jruby.RubyYielder.op_lshift(RubyYielder.java:94)
... 149 levels...
	from org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:75)
	from org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:182)
	from org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:192)
	from org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:312)
	from org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:169)
	from Users.aa.$_dot_rvm.rubies.jruby_minus_1_dot_7_dot_0_dot_preview2.bin.irb.__file__(/Users/aa/.rvm/rubies/jruby-1.7.0.preview2/bin/irb:17)
	from Users.aa.$_dot_rvm.rubies.jruby_minus_1_dot_7_dot_0_dot_preview2.bin.irb.load(/Users/aa/.rvm/rubies/jruby-1.7.0.preview2/bin/irb)
	from org.jruby.Ruby.runScript(Ruby.java:780)
	from org.jruby.Ruby.runScript(Ruby.java:773)
	from org.jruby.Ruby.runNormally(Ruby.java:650)
	from org.jruby.Ruby.runFromMain(Ruby.java:499)
	from org.jruby.Main.doRunFromMain(Main.java:376)
	from org.jruby.Main.internalRun(Main.java:265)
	from org.jruby.Main.run(Main.java:231)
	from org.jruby.Main.run(Main.java:215)
	from org.jruby.Main.main(Main.java:195)

=end