fixes #215, removes special case for length

lib/runtime/dart/_interceptors.js

 dart.library('dart/_interceptors', null, /* Imports */[
   'dart/core',
   'dart/_internal',
   'dart/collection',
   'dart/math'
 ], /* Lazy imports */[
   'dart/_js_helper'
 ], function(exports, core, _internal, collection, math, _js_helper) {
   'use strict';
   let JSArray$ = dart.generic(function(E) {
@@ skipping 77 matching lines @@
         }
       }
       [dartx.add](value) {
         dart.as(value, E);
         this[dartx.checkGrowable]('add');
         this.push(value);
       }
       [dartx.removeAt](index) {
         if (!(typeof index == 'number'))
           throw new core.ArgumentError(index);
-        if (dart.notNull(index) < 0 || dart.notNull(index) >= dart.notNull(this.length)) {
+        if (dart.notNull(index) < 0 || dart.notNull(index) >= dart.notNull(this[dartx.length])) {
           throw new core.RangeError.value(index);
         }
         this[dartx.checkGrowable]('removeAt');
         return this.splice(index, 1)[0];
       }
       [dartx.insert](index, value) {
         dart.as(value, E);
         if (!(typeof index == 'number'))
           throw new core.ArgumentError(index);
-        if (dart.notNull(index) < 0 || dart.notNull(index) > dart.notNull(this.length)) {
+        if (dart.notNull(index) < 0 || dart.notNull(index) > dart.notNull(this[dartx.length])) {
           throw new core.RangeError.value(index);
         }
         this[dartx.checkGrowable]('insert');
         this.splice(index, 0, value);
       }
       [dartx.insertAll](index, iterable) {
         dart.as(iterable, core.Iterable$(E));
         this[dartx.checkGrowable]('insertAll');
         _internal.IterableMixinWorkaround.insertAllList(this, index, iterable);
       }
       [dartx.setAll](index, iterable) {
         dart.as(iterable, core.Iterable$(E));
         _internal.IterableMixinWorkaround.setAllList(this, index, iterable);
       }
       [dartx.removeLast]() {
         this[dartx.checkGrowable]('removeLast');
-        if (this.length == 0)
+        if (this[dartx.length] == 0)
           throw new core.RangeError.value(-1);
         return dart.as(this.pop(), E);
       }
       [dartx.remove](element) {
         this[dartx.checkGrowable]('remove');
-        for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(this[dartx.length]); i = dart.notNull(i) + 1) {
           if (dart.equals(this[dartx.get](i), element)) {
             this.splice(i, 1);
             return true;
           }
         }
         return false;
       }
       [dartx.removeWhere](test) {
         dart.as(test, dart.functionType(core.bool, [E]));
         _internal.IterableMixinWorkaround.removeWhereList(this, test);
@@ skipping 10 matching lines @@
         dart.as(f, dart.functionType(core.Iterable, [E]));
         return _internal.IterableMixinWorkaround.expand(this, f);
       }
       [dartx.addAll](collection) {
         dart.as(collection, core.Iterable$(E));
         for (let e of collection) {
           this[dartx.add](e);
         }
       }
       [dartx.clear]() {
-        this.length = 0;
+        this[dartx.length] = 0;
       }
       [dartx.forEach](f) {
         dart.as(f, dart.functionType(dart.void, [E]));
-        let length = this.length;
+        let length = this[dartx.length];
         for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           f(dart.as(this[i], E));
-          if (length != this.length) {
+          if (length != this[dartx.length]) {
             throw new core.ConcurrentModificationError(this);
           }
         }
       }
       [dartx.map](f) {
         dart.as(f, dart.functionType(core.Object, [E]));
         return _internal.IterableMixinWorkaround.mapList(this, f);
       }
       [dartx.join](separator) {
         if (separator === void 0)
           separator = "";
-        let list = core.List.new(this.length);
-        for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
+        let list = core.List.new(this[dartx.length]);
+        for (let i = 0; dart.notNull(i) < dart.notNull(this[dartx.length]); i = dart.notNull(i) + 1) {
           list[dartx.set](i, `${this[dartx.get](i)}`);
         }
         return list.join(separator);
       }
       [dartx.take](n) {
         return new (_internal.IterableMixinWorkaround$(E))().takeList(this, n);
       }
       [dartx.takeWhile](test) {
         dart.as(test, dart.functionType(core.bool, [E]));
         return new (_internal.IterableMixinWorkaround$(E))().takeWhile(this, test);
@@ skipping 31 matching lines @@
       }
       [dartx.elementAt](index) {
         return this[dartx.get](index);
       }
       [dartx.sublist](start, end) {
         if (end === void 0)
           end = null;
         _js_helper.checkNull(start);
         if (!(typeof start == 'number'))
           throw new core.ArgumentError(start);
-        if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this.length)) {
-          throw new core.RangeError.range(start, 0, this.length);
+        if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this[dartx.length])) {
+          throw new core.RangeError.range(start, 0, this[dartx.length]);
         }
         if (end == null) {
-          end = this.length;
+          end = this[dartx.length];
         } else {
           if (!(typeof end == 'number'))
             throw new core.ArgumentError(end);
-          if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(this.length)) {
-            throw new core.RangeError.range(end, start, this.length);
+          if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(this[dartx.length])) {
+            throw new core.RangeError.range(end, start, this[dartx.length]);
           }
         }
         if (start == end)
           return dart.list([], E);
         return JSArray$(E).typed(this.slice(start, end));
       }
       [dartx.getRange](start, end) {
         return new (_internal.IterableMixinWorkaround$(E))().getRangeList(this, start, end);
       }
       get [dartx.first]() {
-        if (dart.notNull(this.length) > 0)
+        if (dart.notNull(this[dartx.length]) > 0)
           return this[dartx.get](0);
         throw new core.StateError("No elements");
       }
       get [dartx.last]() {
-        if (dart.notNull(this.length) > 0)
-          return this[dartx.get](dart.notNull(this.length) - 1);
+        if (dart.notNull(this[dartx.length]) > 0)
+          return this[dartx.get](dart.notNull(this[dartx.length]) - 1);
         throw new core.StateError("No elements");
       }
       get [dartx.single]() {
-        if (this.length == 1)
+        if (this[dartx.length] == 1)
           return this[dartx.get](0);
-        if (this.length == 0)
+        if (this[dartx.length] == 0)
           throw new core.StateError("No elements");
         throw new core.StateError("More than one element");
       }
       [dartx.removeRange](start, end) {
         this[dartx.checkGrowable]('removeRange');
-        let receiverLength = this.length;
+        let receiverLength = this[dartx.length];
         if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(receiverLength)) {
           throw new core.RangeError.range(start, 0, receiverLength);
         }
         if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(receiverLength)) {
           throw new core.RangeError.range(end, start, receiverLength);
         }
         _internal.Lists.copy(this, end, this, start, dart.notNull(receiverLength) - dart.notNull(end));
-        this.length = dart.notNull(receiverLength) - (dart.notNull(end) - dart.notNull(start));
+        this[dartx.length] = dart.notNull(receiverLength) - (dart.notNull(end) - dart.notNull(start));
       }
       [dartx.setRange](start, end, iterable, skipCount) {
         dart.as(iterable, core.Iterable$(E));
         if (skipCount === void 0)
           skipCount = 0;
         _internal.IterableMixinWorkaround.setRangeList(this, start, end, iterable, skipCount);
       }
       [dartx.fillRange](start, end, fillValue) {
         if (fillValue === void 0)
           fillValue = null;
@@ skipping 30 matching lines @@
         if (start === void 0)
           start = 0;
         return _internal.IterableMixinWorkaround.indexOfList(this, element, start);
       }
       [dartx.lastIndexOf](element, start) {
         if (start === void 0)
           start = null;
         return _internal.IterableMixinWorkaround.lastIndexOfList(this, element, start);
       }
       [dartx.contains](other) {
-        for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(this[dartx.length]); i = dart.notNull(i) + 1) {
           if (dart.equals(this[dartx.get](i), other))
             return true;
         }
         return false;
       }
       get [dartx.isEmpty]() {
-        return this.length == 0;
+        return this[dartx.length] == 0;
       }
       get [dartx.isNotEmpty]() {
         return !dart.notNull(this[dartx.isEmpty]);
       }
       [dartx.toString]() {
         return collection.ListBase.listToString(this);
       }
       [dartx.toList](opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let list = this.slice();
         if (!dart.notNull(growable))
           JSArray$().markFixedList(dart.as(list, core.List));
         return JSArray$(E).typed(list);
       }
       [dartx.toSet]() {
         return core.Set$(E).from(this);
       }
       get [dartx.iterator]() {
         return new (_internal.ListIterator$(E))(this);
       }
       get [dartx.hashCode]() {
         return _js_helper.Primitives.objectHashCode(this);
       }
-      get length() {
+      get [dartx.length]() {
         return dart.as(this.length, core.int);
       }
-      set length(newLength) {
+      set [dartx.length](newLength) {
         if (!(typeof newLength == 'number'))
           throw new core.ArgumentError(newLength);
         if (dart.notNull(newLength) < 0)
           throw new core.RangeError.value(newLength);
         this[dartx.checkGrowable]('set length');
         this.length = newLength;
       }
       [dartx.get](index) {
         if (!(typeof index == 'number'))
           throw new core.ArgumentError(index);
-        if (dart.notNull(index) >= dart.notNull(this.length) || dart.notNull(index) < 0)
+        if (dart.notNull(index) >= dart.notNull(this[dartx.length]) || dart.notNull(index) < 0)
           throw new core.RangeError.value(index);
         return dart.as(this[index], E);
       }
       [dartx.set](index, value) {
         dart.as(value, E);
         if (!(typeof index == 'number'))
           throw new core.ArgumentError(index);
-        if (dart.notNull(index) >= dart.notNull(this.length) || dart.notNull(index) < 0)
+        if (dart.notNull(index) >= dart.notNull(this[dartx.length]) || dart.notNull(index) < 0)
           throw new core.RangeError.value(index);
         this[index] = value;
       }
       [dartx.asMap]() {
         return new (_internal.IterableMixinWorkaround$(E))().asMapList(this);
       }
     }
     dart.setBaseClass(JSArray, dart.global.Array);
     JSArray[dart.implements] = () => [core.List$(E), JSIndexable];
     dart.setSignature(JSArray, {
@@ skipping 236 matching lines @@
       if (dart.equals(this, 0) && dart.notNull(this[dartx.isNegative]))
         return `-${result}`;
       return result;
     }
     [dartx.toRadixString](radix) {
       _js_helper.checkInt(radix);
       if (dart.notNull(radix) < 2 || dart.notNull(radix) > 36)
         throw new core.RangeError(radix);
       let result = this.toString(radix);
       let rightParenCode = 41;
-      if (result[dartx.codeUnitAt](dart.notNull(result.length) - 1) != rightParenCode) {
+      if (result[dartx.codeUnitAt](dart.notNull(result[dartx.length]) - 1) != rightParenCode) {
         return result;
       }
       return JSNumber._handleIEtoString(result);
     }
     static _handleIEtoString(result) {
       let match = /^([\da-z]+)(?:\.([\da-z]+))?\(e\+(\d+)\)$/.exec(result);
       if (match == null) {
         throw new core.UnsupportedError(`Unexpected toString result: ${result}`);
       }
       result = dart.dindex(match, 1);
@@ skipping 333 matching lines @@
   ]);
   class JSString extends Interceptor {
     JSString() {
       super.Interceptor();
     }
     [dartx.codeUnitAt](index) {
       if (!(typeof index == 'number'))
         throw new core.ArgumentError(index);
       if (dart.notNull(index) < 0)
         throw new core.RangeError.value(index);
-      if (dart.notNull(index) >= dart.notNull(this.length))
+      if (dart.notNull(index) >= dart.notNull(this[dartx.length]))
         throw new core.RangeError.value(index);
       return dart.as(this.charCodeAt(index), core.int);
     }
     [dartx.allMatches](string, start) {
       if (start === void 0)
         start = 0;
       _js_helper.checkString(string);
       _js_helper.checkInt(start);
-      if (0 > dart.notNull(start) || dart.notNull(start) > dart.notNull(string.length)) {
-        throw new core.RangeError.range(start, 0, string.length);
+      if (0 > dart.notNull(start) || dart.notNull(start) > dart.notNull(string[dartx.length])) {
+        throw new core.RangeError.range(start, 0, string[dartx.length]);
       }
       return _js_helper.allMatchesInStringUnchecked(this, string, start);
     }
     [dartx.matchAsPrefix](string, start) {
       if (start === void 0)
         start = 0;
-      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(string.length)) {
-        throw new core.RangeError.range(start, 0, string.length);
+      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(string[dartx.length])) {
+        throw new core.RangeError.range(start, 0, string[dartx.length]);
       }
-      if (dart.notNull(start) + dart.notNull(this.length) > dart.notNull(string.length))
+      if (dart.notNull(start) + dart.notNull(this[dartx.length]) > dart.notNull(string[dartx.length]))
         return null;
-      for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(this[dartx.length]); i = dart.notNull(i) + 1) {
         if (string[dartx.codeUnitAt](dart.notNull(start) + dart.notNull(i)) != this[dartx.codeUnitAt](i)) {
           return null;
         }
       }
       return new _js_helper.StringMatch(start, string, this);
     }
     [dartx['+']](other) {
       if (!(typeof other == 'string'))
         throw new core.ArgumentError(other);
       return this + other;
     }
     [dartx.endsWith](other) {
       _js_helper.checkString(other);
-      let otherLength = other.length;
-      if (dart.notNull(otherLength) > dart.notNull(this.length))
+      let otherLength = other[dartx.length];
+      if (dart.notNull(otherLength) > dart.notNull(this[dartx.length]))
         return false;
-      return other == this[dartx.substring](dart.notNull(this.length) - dart.notNull(otherLength));
+      return other == this[dartx.substring](dart.notNull(this[dartx.length]) - dart.notNull(otherLength));
     }
     [dartx.replaceAll](from, to) {
       _js_helper.checkString(to);
       return dart.as(_js_helper.stringReplaceAllUnchecked(this, from, to), core.String);
     }
     [dartx.replaceAllMapped](from, convert) {
       return this[dartx.splitMapJoin](from, {onMatch: convert});
     }
     [dartx.splitMapJoin](from, opts) {
       let onMatch = opts && 'onMatch' in opts ? opts.onMatch : null;
       let onNonMatch = opts && 'onNonMatch' in opts ? opts.onNonMatch : null;
       return dart.as(_js_helper.stringReplaceAllFuncUnchecked(this, from, onMatch, onNonMatch), core.String);
     }
     [dartx.replaceFirst](from, to, startIndex) {
       if (startIndex === void 0)
         startIndex = 0;
       _js_helper.checkString(to);
       _js_helper.checkInt(startIndex);
-      if (dart.notNull(startIndex) < 0 || dart.notNull(startIndex) > dart.notNull(this.length)) {
-        throw new core.RangeError.range(startIndex, 0, this.length);
+      if (dart.notNull(startIndex) < 0 || dart.notNull(startIndex) > dart.notNull(this[dartx.length])) {
+        throw new core.RangeError.range(startIndex, 0, this[dartx.length]);
       }
       return dart.as(_js_helper.stringReplaceFirstUnchecked(this, from, to, startIndex), core.String);
     }
     [dartx.split](pattern) {
       _js_helper.checkNull(pattern);
       if (typeof pattern == 'string') {
         return dart.as(this.split(pattern), core.List$(core.String));
       } else if (dart.is(pattern, _js_helper.JSSyntaxRegExp) && _js_helper.regExpCaptureCount(pattern) == 0) {
         let re = _js_helper.regExpGetNative(pattern);
         return dart.as(this.split(re), core.List$(core.String));
       } else {
         return this[_defaultSplit](pattern);
       }
     }
     [_defaultSplit](pattern) {
       let result = dart.list([], core.String);
       let start = 0;
       let length = 1;
       for (let match of pattern[dartx.allMatches](this)) {
         let matchStart = match.start;
         let matchEnd = match.end;
         length = dart.notNull(matchEnd) - dart.notNull(matchStart);
         if (length == 0 && start == matchStart) {
           continue;
         }
         let end = matchStart;
         result[dartx.add](this[dartx.substring](start, end));
         start = matchEnd;
       }
-      if (dart.notNull(start) < dart.notNull(this.length) || dart.notNull(length) > 0) {
+      if (dart.notNull(start) < dart.notNull(this[dartx.length]) || dart.notNull(length) > 0) {
         result[dartx.add](this[dartx.substring](start));
       }
       return result;
     }
     [dartx.startsWith](pattern, index) {
       if (index === void 0)
         index = 0;
       _js_helper.checkInt(index);
-      if (dart.notNull(index) < 0 || dart.notNull(index) > dart.notNull(this.length)) {
-        throw new core.RangeError.range(index, 0, this.length);
+      if (dart.notNull(index) < 0 || dart.notNull(index) > dart.notNull(this[dartx.length])) {
+        throw new core.RangeError.range(index, 0, this[dartx.length]);
       }
       if (typeof pattern == 'string') {
         let other = pattern;
-        let otherLength = other.length;
+        let otherLength = other[dartx.length];
         let endIndex = dart.notNull(index) + dart.notNull(otherLength);
-        if (dart.notNull(endIndex) > dart.notNull(this.length))
+        if (dart.notNull(endIndex) > dart.notNull(this[dartx.length]))
           return false;
         return other == this.substring(index, endIndex);
       }
       return pattern[dartx.matchAsPrefix](this, index) != null;
     }
     [dartx.substring](startIndex, endIndex) {
       if (endIndex === void 0)
         endIndex = null;
       _js_helper.checkInt(startIndex);
       if (endIndex == null)
-        endIndex = this.length;
+        endIndex = this[dartx.length];
       _js_helper.checkInt(endIndex);
       if (dart.notNull(startIndex) < 0)
         throw new core.RangeError.value(startIndex);
       if (dart.notNull(startIndex) > dart.notNull(endIndex))
         throw new core.RangeError.value(startIndex);
-      if (dart.notNull(endIndex) > dart.notNull(this.length))
+      if (dart.notNull(endIndex) > dart.notNull(this[dartx.length]))
         throw new core.RangeError.value(endIndex);
       return this.substring(startIndex, endIndex);
     }
     [dartx.toLowerCase]() {
       return this.toLowerCase();
     }
     [dartx.toUpperCase]() {
       return this.toUpperCase();
     }
     static _isWhitespace(codeUnit) {
@@ skipping 41 matching lines @@
         }
         default:
         {
           return false;
         }
       }
     }
     static _skipLeadingWhitespace(string, index) {
       let SPACE = 32;
       let CARRIAGE_RETURN = 13;
-      while (dart.notNull(index) < dart.notNull(string.length)) {
+      while (dart.notNull(index) < dart.notNull(string[dartx.length])) {
         let codeUnit = string[dartx.codeUnitAt](index);
         if (codeUnit != SPACE && codeUnit != CARRIAGE_RETURN && !dart.notNull(JSString._isWhitespace(codeUnit))) {
           break;
         }
         index = dart.notNull(index) + 1;
       }
       return index;
     }
     static _skipTrailingWhitespace(string, index) {
       let SPACE = 32;
       let CARRIAGE_RETURN = 13;
       while (dart.notNull(index) > 0) {
         let codeUnit = string[dartx.codeUnitAt](dart.notNull(index) - 1);
         if (codeUnit != SPACE && codeUnit != CARRIAGE_RETURN && !dart.notNull(JSString._isWhitespace(codeUnit))) {
           break;
         }
         index = dart.notNull(index) - 1;
       }
       return index;
     }
     [dartx.trim]() {
       let NEL = 133;
       let result = this.trim();
-      if (result.length == 0)
+      if (result[dartx.length] == 0)
         return result;
       let firstCode = result[dartx.codeUnitAt](0);
       let startIndex = 0;
       if (firstCode == NEL) {
         startIndex = JSString._skipLeadingWhitespace(result, 1);
-        if (startIndex == result.length)
+        if (startIndex == result[dartx.length])
           return "";
       }
-      let endIndex = result.length;
+      let endIndex = result[dartx.length];
       let lastCode = result[dartx.codeUnitAt](dart.notNull(endIndex) - 1);
       if (lastCode == NEL) {
         endIndex = JSString._skipTrailingWhitespace(result, dart.notNull(endIndex) - 1);
       }
-      if (startIndex == 0 && endIndex == result.length)
+      if (startIndex == 0 && endIndex == result[dartx.length])
         return result;
       return result.substring(startIndex, endIndex);
     }
     [dartx.trimLeft]() {
       let NEL = 133;
       let result = null;
       let startIndex = 0;
       if (typeof this.trimLeft != "undefined") {
         result = this.trimLeft();
-        if (result.length == 0)
+        if (result[dartx.length] == 0)
           return result;
         let firstCode = result[dartx.codeUnitAt](0);
         if (firstCode == NEL) {
           startIndex = JSString._skipLeadingWhitespace(result, 1);
         }
       } else {
         result = this;
         startIndex = JSString._skipLeadingWhitespace(this, 0);
       }
       if (startIndex == 0)
         return result;
-      if (startIndex == result.length)
+      if (startIndex == result[dartx.length])
         return "";
       return result.substring(startIndex);
     }
     [dartx.trimRight]() {
       let NEL = 133;
       let result = null;
       let endIndex = null;
       if (typeof this.trimRight != "undefined") {
         result = this.trimRight();
-        endIndex = result.length;
+        endIndex = result[dartx.length];
         if (endIndex == 0)
           return result;
         let lastCode = result[dartx.codeUnitAt](dart.notNull(endIndex) - 1);
         if (lastCode == NEL) {
           endIndex = JSString._skipTrailingWhitespace(result, dart.notNull(endIndex) - 1);
         }
       } else {
         result = this;
-        endIndex = JSString._skipTrailingWhitespace(this, this.length);
+        endIndex = JSString._skipTrailingWhitespace(this, this[dartx.length]);
       }
-      if (endIndex == result.length)
+      if (endIndex == result[dartx.length])
         return result;
       if (endIndex == 0)
         return "";
       return result.substring(0, endIndex);
     }
     [dartx['*']](times) {
       if (0 >= dart.notNull(times))
         return '';
-      if (times == 1 || this.length == 0)
+      if (times == 1 || this[dartx.length] == 0)
         return this;
       if (!dart.equals(times, times >>> 0)) {
         throw dart.const(new core.OutOfMemoryError());
       }
       let result = '';
       let s = this;
       while (true) {
         if ((dart.notNull(times) & 1) == 1)
           result = s[dartx['+']](result);
         times = dart.as(times >>> 1, core.int);
         if (times == 0)
           break;
         s = s[dartx['+']](s);
       }
       return result;
     }
     [dartx.padLeft](width, padding) {
       if (padding === void 0)
         padding = ' ';
-      let delta = dart.notNull(width) - dart.notNull(this.length);
+      let delta = dart.notNull(width) - dart.notNull(this[dartx.length]);
       if (dart.notNull(delta) <= 0)
         return this;
       return padding[dartx['*']](delta) + this;
     }
     [dartx.padRight](width, padding) {
       if (padding === void 0)
         padding = ' ';
-      let delta = dart.notNull(width) - dart.notNull(this.length);
+      let delta = dart.notNull(width) - dart.notNull(this[dartx.length]);
       if (dart.notNull(delta) <= 0)
         return this;
       return this[dartx['+']](padding[dartx['*']](delta));
     }
     get [dartx.codeUnits]() {
       return new _CodeUnits(this);
     }
     get [dartx.runes]() {
       return new core.Runes(this);
     }
     [dartx.indexOf](pattern, start) {
       if (start === void 0)
         start = 0;
       _js_helper.checkNull(pattern);
       if (!(typeof start == 'number'))
         throw new core.ArgumentError(start);
-      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this.length)) {
-        throw new core.RangeError.range(start, 0, this.length);
+      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this[dartx.length])) {
+        throw new core.RangeError.range(start, 0, this[dartx.length]);
       }
       if (typeof pattern == 'string') {
         return this.indexOf(pattern, start);
       }
       if (dart.is(pattern, _js_helper.JSSyntaxRegExp)) {
         let re = pattern;
         let match = _js_helper.firstMatchAfter(re, this, start);
         return match == null ? -1 : match.start;
       }
-      for (let i = start; dart.notNull(i) <= dart.notNull(this.length); i = dart.notNull(i) + 1) {
+      for (let i = start; dart.notNull(i) <= dart.notNull(this[dartx.length]); i = dart.notNull(i) + 1) {
         if (pattern[dartx.matchAsPrefix](this, i) != null)
           return i;
       }
       return -1;
     }
     [dartx.lastIndexOf](pattern, start) {
       if (start === void 0)
         start = null;
       _js_helper.checkNull(pattern);
       if (start == null) {
-        start = this.length;
+        start = this[dartx.length];
       } else if (!(typeof start == 'number')) {
         throw new core.ArgumentError(start);
-      } else if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this.length)) {
-        throw new core.RangeError.range(start, 0, this.length);
+      } else if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this[dartx.length])) {
+        throw new core.RangeError.range(start, 0, this[dartx.length]);
       }
       if (typeof pattern == 'string') {
         let other = pattern;
-        if (dart.notNull(start) + dart.notNull(other.length) > dart.notNull(this.length)) {
-          start = dart.notNull(this.length) - dart.notNull(other.length);
+        if (dart.notNull(start) + dart.notNull(other[dartx.length]) > dart.notNull(this[dartx.length])) {
+          start = dart.notNull(this[dartx.length]) - dart.notNull(other[dartx.length]);
         }
         return dart.as(_js_helper.stringLastIndexOfUnchecked(this, other, start), core.int);
       }
       for (let i = start; dart.notNull(i) >= 0; i = dart.notNull(i) - 1) {
         if (pattern[dartx.matchAsPrefix](this, i) != null)
           return i;
       }
       return -1;
     }
     [dartx.contains](other, startIndex) {
       if (startIndex === void 0)
         startIndex = 0;
       _js_helper.checkNull(other);
-      if (dart.notNull(startIndex) < 0 || dart.notNull(startIndex) > dart.notNull(this.length)) {
-        throw new core.RangeError.range(startIndex, 0, this.length);
+      if (dart.notNull(startIndex) < 0 || dart.notNull(startIndex) > dart.notNull(this[dartx.length])) {
+        throw new core.RangeError.range(startIndex, 0, this[dartx.length]);
       }
       return dart.as(_js_helper.stringContainsUnchecked(this, other, startIndex), core.bool);
     }
     get [dartx.isEmpty]() {
-      return this.length == 0;
+      return this[dartx.length] == 0;
     }
     get [dartx.isNotEmpty]() {
       return !dart.notNull(this[dartx.isEmpty]);
     }
     [dartx.compareTo](other) {
       if (!(typeof other == 'string'))
         throw new core.ArgumentError(other);
       return dart.equals(this, other) ? 0 : this < other ? -1 : 1;
     }
     [dartx.toString]() {
       return this;
     }
     get [dartx.hashCode]() {
       let hash = 0;
-      for (let i = 0; dart.notNull(i) < dart.notNull(this.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(this[dartx.length]); i = dart.notNull(i) + 1) {
         hash = 536870911 & dart.notNull(hash) + this.charCodeAt(i);
         hash = 536870911 & dart.notNull(hash) + ((524287 & dart.notNull(hash)) << 10);
         hash = hash ^ hash >> 6;
       }
       hash = 536870911 & dart.notNull(hash) + ((67108863 & dart.notNull(hash)) << 3);
       hash = hash ^ hash >> 11;
       return 536870911 & dart.notNull(hash) + ((16383 & dart.notNull(hash)) << 15);
     }
     get [dartx.runtimeType]() {
       return core.String;
     }
-    get length() {
+    get [dartx.length]() {
       return this.length;
     }
     [dartx.get](index) {
       if (!(typeof index == 'number'))
         throw new core.ArgumentError(index);
-      if (dart.notNull(index) >= dart.notNull(this.length) || dart.notNull(index) < 0)
+      if (dart.notNull(index) >= dart.notNull(this[dartx.length]) || dart.notNull(index) < 0)
         throw new core.RangeError.value(index);
       return this[index];
     }
   }
   JSString[dart.implements] = () => [core.String, JSIndexable];
   dart.setSignature(JSString, {
     constructors: () => ({JSString: [JSString, []]}),
     methods: () => ({
       [dartx.codeUnitAt]: [core.int, [core.int]],
       [dartx.allMatches]: [core.Iterable$(core.Match), [core.String], [core.int]],
@@ skipping 30 matching lines @@
     names: ['_isWhitespace', '_skipLeadingWhitespace', '_skipTrailingWhitespace']
   });
   JSString[dart.metadata] = () => [dart.const(new _js_helper.JsPeerInterface({name: 'String'}))];
   dart.registerExtension(dart.global.String, JSString);
   let _string = Symbol('_string');
   class _CodeUnits extends _internal.UnmodifiableListBase$(core.int) {
     _CodeUnits(string) {
       this[_string] = string;
     }
     get length() {
-      return this[_string].length;
+      return this[_string][dartx.length];
     }
     get(i) {
       return this[_string][dartx.codeUnitAt](i);
     }
   }
   dart.setSignature(_CodeUnits, {
     constructors: () => ({_CodeUnits: [_CodeUnits, [core.String]]}),
     methods: () => ({get: [core.int, [core.int]]})
   });
   dart.defineExtensionMembers(_CodeUnits, ['get', 'length']);
@@ skipping 82 matching lines @@
   exports.JSString = JSString;
   exports.getInterceptor = getInterceptor;
   exports.JSBool = JSBool;
   exports.JSIndexable = JSIndexable;
   exports.JSMutableIndexable = JSMutableIndexable;
   exports.JSObject = JSObject;
   exports.JavaScriptObject = JavaScriptObject;
   exports.PlainJavaScriptObject = PlainJavaScriptObject;
   exports.UnknownJavaScriptObject = UnknownJavaScriptObject;
 });