FULL PRODUCT VERSION :
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Darwin c056.local 14.5.0 Darwin Kernel Version 14.5.0: Wed Jul 29 02:26:53 PDT 2015; root:xnu-2782.40.9~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
The following code incorrectly produces `4` in Nashorn (it should produce `2`):

(function(f){
  return function(a1, a2, a3, a4){
    return f.apply(this, arguments);
  }
})
(function(){
  return arguments.length;
})
(1, 2);

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Observe that the code provided in the description produces an incorrect result when run through Nashorn.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
2, the number of arguments with which the function is called.
ACTUAL -
4, the number of formal parameters of the function.

REPRODUCIBILITY :
This bug can be reproduced always.