ensure clause is executed before begin clause ends ?

[yamam]

The following script raises StackOverflowError.

var = true

proc1 = proc do
    if var
        begin
            var = false
            proc1.call
        ensure
            var = true
        end
    end
end

proc1.call

jruby 9.0.0.0 (2.2.2) 2015-07-21 e10ec96 Java HotSpot(TM) Client VM 25.51-b03 on 1.8.0_51-b16 +jit [Windows 7-x86]
io/console not supported; tty will not be manipulated
Error: Your application used more stack memory than the safety cap of 2048K.
Specify -J-Xss####k to increase it (#### = cap size in KB).
Exception trace follows:
java.lang.StackOverflowError
        at test.RUBY$block$\=test\,rb$0(test.rb:7)
        at org.jruby.runtime.CompiledIRBlockBody.commonYieldPath(CompiledIRBlockBody.java:70)
        at org.jruby.runtime.IRBlockBody.call(IRBlockBody.java:58)
        at org.jruby.runtime.Block.call(Block.java:106)
        at org.jruby.RubyProc.call(RubyProc.java:324)
        at org.jruby.RubyProc.call19(RubyProc.java:308)
        at org.jruby.RubyProc$INVOKER$i$0$0$call19.call(RubyProc$INVOKER$i$0$0$call19.gen)
        at org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:197)
        at org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:193)
        at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:129)
        at test.invokeOther0:call(test.rb)
        at test.RUBY$block$\=test\,rb$0(test.rb:7)
        at org.jruby.runtime.CompiledIRBlockBody.commonYieldPath(CompiledIRBlockBody.java:70)
        at org.jruby.runtime.IRBlockBody.call(IRBlockBody.java:58)
        at org.jruby.runtime.Block.call(Block.java:106)
        ...

[subbuss]

This is a bug in LVA. It doesn't realize 'var' is still alive after the 'var = false' assignment which leads DCE to remove it.