128         if (sobj.isScope()) {
 129             return createGlobalPropertySetter();
 130         }
 131 
 132         return createNewPropertySetter(builtinSwitchPoint);
 133     }
 134 
 135     private void checkStrictCreateNewVariable() {
 136         // In strict mode, assignment can not create a new variable.
 137         // See also ECMA Annex C item 4. ReferenceError is thrown.
 138         if (NashornCallSiteDescriptor.isScope(desc) && NashornCallSiteDescriptor.isStrict(desc)) {
 139             throw referenceError("not.defined", getName());
 140         }
 141     }
 142 
 143     private SetMethod createExistingPropertySetter() {
 144         final Property property = find.getProperty();
 145         final boolean isStrict  = NashornCallSiteDescriptor.isStrict(desc);
 146         final MethodHandle methodHandle;
 147 
 148         if (NashornCallSiteDescriptor.isDeclaration(desc)) {
 149             assert property.needsDeclaration();
 150             // This is a LET or CONST being declared. The property is already there but flagged as needing declaration.
 151             // We create a new PropertyMap with the flag removed. The map is installed with a fast compare-and-set
 152             // method if the pre-callsite map is stable (which should be the case for function scopes except for
 153             // non-strict functions containing eval() with var). Otherwise we have to use a slow setter that creates
 154             // a new PropertyMap on the fly.
 155             final PropertyMap oldMap = getMap();
 156             final Property newProperty = property.removeFlags(Property.NEEDS_DECLARATION);
 157             final PropertyMap newMap = oldMap.replaceProperty(property, newProperty);
 158             final MethodHandle fastSetter = find.replaceProperty(newProperty).getSetter(type, isStrict, request);
 159             final MethodHandle slowSetter = MH.insertArguments(ScriptObject.DECLARE_AND_SET, 1, getName()).asType(fastSetter.type());
 160 
 161             // cas map used as guard, if true that means we can do the set fast
 162             MethodHandle casMap = MH.insertArguments(ScriptObject.CAS_MAP, 1, oldMap, newMap);
 163             casMap = MH.dropArguments(casMap, 1, type);
 164             casMap = MH.asType(casMap, casMap.type().changeParameterType(0, Object.class));
 165             methodHandle = MH.guardWithTest(casMap, fastSetter, slowSetter);
 166         } else {
 167             methodHandle = find.getSetter(type, isStrict, request);
 168         }
 169 

 128         if (sobj.isScope()) {
 129             return createGlobalPropertySetter();
 130         }
 131 
 132         return createNewPropertySetter(builtinSwitchPoint);
 133     }
 134 
 135     private void checkStrictCreateNewVariable() {
 136         // In strict mode, assignment can not create a new variable.
 137         // See also ECMA Annex C item 4. ReferenceError is thrown.
 138         if (NashornCallSiteDescriptor.isScope(desc) && NashornCallSiteDescriptor.isStrict(desc)) {
 139             throw referenceError("not.defined", getName());
 140         }
 141     }
 142 
 143     private SetMethod createExistingPropertySetter() {
 144         final Property property = find.getProperty();
 145         final boolean isStrict  = NashornCallSiteDescriptor.isStrict(desc);
 146         final MethodHandle methodHandle;
 147 
 148         if (NashornCallSiteDescriptor.isDeclaration(desc) && property.needsDeclaration()) {

 149             // This is a LET or CONST being declared. The property is already there but flagged as needing declaration.
 150             // We create a new PropertyMap with the flag removed. The map is installed with a fast compare-and-set
 151             // method if the pre-callsite map is stable (which should be the case for function scopes except for
 152             // non-strict functions containing eval() with var). Otherwise we have to use a slow setter that creates
 153             // a new PropertyMap on the fly.
 154             final PropertyMap oldMap = getMap();
 155             final Property newProperty = property.removeFlags(Property.NEEDS_DECLARATION);
 156             final PropertyMap newMap = oldMap.replaceProperty(property, newProperty);
 157             final MethodHandle fastSetter = find.replaceProperty(newProperty).getSetter(type, isStrict, request);
 158             final MethodHandle slowSetter = MH.insertArguments(ScriptObject.DECLARE_AND_SET, 1, getName()).asType(fastSetter.type());
 159 
 160             // cas map used as guard, if true that means we can do the set fast
 161             MethodHandle casMap = MH.insertArguments(ScriptObject.CAS_MAP, 1, oldMap, newMap);
 162             casMap = MH.dropArguments(casMap, 1, type);
 163             casMap = MH.asType(casMap, casMap.type().changeParameterType(0, Object.class));
 164             methodHandle = MH.guardWithTest(casMap, fastSetter, slowSetter);
 165         } else {
 166             methodHandle = find.getSetter(type, isStrict, request);
 167         }
 168