masgn an expression (array is needed):

    LINENUMBER 1 L0
    ALOAD 1
    ICONST_0
    INVOKESTATIC ruby/__dash_e__.setPosition (Lorg/jruby/runtime/ThreadContext;I)V
    ALOAD 6
    ALOAD 6
    INVOKESTATIC org/jruby/RubyFixnum.one (Lorg/jruby/Ruby;)Lorg/jruby/RubyFixnum;
    ALOAD 6
    INVOKESTATIC org/jruby/RubyFixnum.two (Lorg/jruby/Ruby;)Lorg/jruby/RubyFixnum;
    INVOKESTATIC org/jruby/javasupport/util/RuntimeHelpers.constructRubyArray (Lorg/jruby/Ruby;Lorg/jruby/runtime/builtin/IRubyObject;Lorg/jruby/runtime/builtin/IRubyObject;)Lorg/jruby/RubyArray;
    ALOAD 6
    ICONST_1
    INVOKESTATIC org/jruby/javasupport/util/RuntimeHelpers.ensureMultipleAssignableRubyArray (Lorg/jruby/runtime/builtin/IRubyObject;Lorg/jruby/Ruby;Z)Lorg/jruby/RubyArray;
    ASTORE 13
    ALOAD 13
    INVOKESTATIC org/jruby/javasupport/util/RuntimeHelpers.arrayEntryOrNilZero (Lorg/jruby/RubyArray;)Lorg/jruby/runtime/builtin/IRubyObject;
    ASTORE 11
    ALOAD 13
    INVOKESTATIC org/jruby/javasupport/util/RuntimeHelpers.arrayEntryOrNilOne (Lorg/jruby/RubyArray;)Lorg/jruby/runtime/builtin/IRubyObject;
    ASTORE 12
    ALOAD 13
    ARETURN

masgn not an expression:

    LINENUMBER 1 L0
    ALOAD 1
    ICONST_0
    INVOKESTATIC ruby/__dash_e__.setPosition (Lorg/jruby/runtime/ThreadContext;I)V
    ALOAD 6
    INVOKESTATIC org/jruby/RubyFixnum.one (Lorg/jruby/Ruby;)Lorg/jruby/RubyFixnum;
    ALOAD 6
    INVOKESTATIC org/jruby/RubyFixnum.two (Lorg/jruby/Ruby;)Lorg/jruby/RubyFixnum;
    SWAP
    ASTORE 11
    ASTORE 12
    ALOAD 6
    INVOKESTATIC org/jruby/RubyFixnum.one (Lorg/jruby/Ruby;)Lorg/jruby/RubyFixnum;
    ARETURN