From d52346c20140bc046b4a7e361f8fc0742e7a1388 Mon Sep 17 00:00:00 2001
From: John Messerly <jmesserly@google.com>
Date: Wed, 10 Jun 2015 12:21:49 -0700
Subject: [PATCH] fixes #215, removes special case for length

R=vsm@google.com

Review URL: https://codereview.chromium.org/1178523004.
---
 .../lib/runtime/dart/_interceptors.js         | 150 +++++++++---------
 .../lib/runtime/dart/_internal.js             | 106 ++++++-------
 .../lib/runtime/dart/_isolate_helper.js       |  16 +-
 .../lib/runtime/dart/_js_helper.js            |  28 ++--
 .../lib/runtime/dart/_native_typed_data.js    |  16 +-
 .../lib/runtime/dart/collection.js            | 126 +++++++--------
 pkg/dev_compiler/lib/runtime/dart/convert.js  | 106 ++++++-------
 pkg/dev_compiler/lib/runtime/dart/core.js     | 126 +++++++--------
 pkg/dev_compiler/lib/runtime/dart/isolate.js  |   2 +-
 .../lib/src/codegen/js_codegen.dart           |   3 +-
 .../test/codegen/expect/BenchmarkBase.js      |   6 +-
 .../test/codegen/expect/DeltaBlue.js          |  20 +--
 .../test/codegen/expect/cascade.js            |   6 +-
 13 files changed, 355 insertions(+), 356 deletions(-)

diff --git a/pkg/dev_compiler/lib/runtime/dart/_interceptors.js b/pkg/dev_compiler/lib/runtime/dart/_interceptors.js
index 658cf7971923..615c98079d6b 100644
--- a/pkg/dev_compiler/lib/runtime/dart/_interceptors.js
+++ b/pkg/dev_compiler/lib/runtime/dart/_interceptors.js
@@ -95,7 +95,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
       [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');
@@ -105,7 +105,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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');
@@ -122,13 +122,13 @@ dart.library('dart/_interceptors', null, /* Imports */[
       }
       [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;
@@ -159,14 +159,14 @@ dart.library('dart/_interceptors', null, /* Imports */[
         }
       }
       [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);
           }
         }
@@ -178,8 +178,8 @@ dart.library('dart/_interceptors', null, /* Imports */[
       [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, `${this[dartx.get](i)}`);
         }
         return list.join(separator);
@@ -231,16 +231,16 @@ dart.library('dart/_interceptors', null, /* Imports */[
         _js_helper.checkNull(start);
         if (!(typeof start == 'number'))
           throw new core.ArgumentError(start);
-        if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this.length)) {
-          throw new core.RangeError.range(start, 0, this.length);
+        if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(this[dartx.length])) {
+          throw new core.RangeError.range(start, 0, this[dartx.length]);
         }
         if (end == null) {
-          end = this.length;
+          end = this[dartx.length];
         } else {
           if (!(typeof end == 'number'))
             throw new core.ArgumentError(end);
-          if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(this.length)) {
-            throw new core.RangeError.range(end, start, this.length);
+          if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(this[dartx.length])) {
+            throw new core.RangeError.range(end, start, this[dartx.length]);
           }
         }
         if (start == end)
@@ -251,25 +251,25 @@ dart.library('dart/_interceptors', null, /* Imports */[
         return new (_internal.IterableMixinWorkaround$(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);
         }
@@ -277,7 +277,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
           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));
@@ -328,14 +328,14 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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]);
@@ -359,10 +359,10 @@ dart.library('dart/_interceptors', null, /* Imports */[
       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)
@@ -373,7 +373,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
       [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);
       }
@@ -381,7 +381,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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;
       }
@@ -638,7 +638,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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);
@@ -992,7 +992,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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);
     }
@@ -1001,20 +1001,20 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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;
         }
@@ -1028,10 +1028,10 @@ dart.library('dart/_interceptors', null, /* Imports */[
     }
     [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);
@@ -1050,8 +1050,8 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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);
     }
@@ -1081,7 +1081,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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;
@@ -1090,14 +1090,14 @@ dart.library('dart/_interceptors', null, /* Imports */[
       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);
       }
@@ -1108,13 +1108,13 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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);
     }
@@ -1176,7 +1176,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
     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;
@@ -1200,21 +1200,21 @@ dart.library('dart/_interceptors', null, /* Imports */[
     [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);
     }
@@ -1224,7 +1224,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
       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) {
@@ -1236,7 +1236,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
       }
       if (startIndex == 0)
         return result;
-      if (startIndex == result.length)
+      if (startIndex == result[dartx.length])
         return "";
       return result.substring(startIndex);
     }
@@ -1246,7 +1246,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
       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);
@@ -1255,9 +1255,9 @@ dart.library('dart/_interceptors', null, /* Imports */[
         }
       } 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 "";
@@ -1266,7 +1266,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
     [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());
@@ -1286,7 +1286,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
     [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;
@@ -1294,7 +1294,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
     [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));
@@ -1311,8 +1311,8 @@ dart.library('dart/_interceptors', null, /* Imports */[
       _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);
@@ -1322,7 +1322,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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;
       }
@@ -1333,16 +1333,16 @@ dart.library('dart/_interceptors', null, /* Imports */[
         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);
       }
@@ -1356,13 +1356,13 @@ dart.library('dart/_interceptors', null, /* Imports */[
       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]);
@@ -1377,7 +1377,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
     }
     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;
@@ -1389,13 +1389,13 @@ dart.library('dart/_interceptors', null, /* Imports */[
     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];
     }
@@ -1446,7 +1446,7 @@ dart.library('dart/_interceptors', null, /* Imports */[
       this[_string] = string;
     }
     get length() {
-      return this[_string].length;
+      return this[_string][dartx.length];
     }
     get(i) {
       return this[_string][dartx.codeUnitAt](i);
diff --git a/pkg/dev_compiler/lib/runtime/dart/_internal.js b/pkg/dev_compiler/lib/runtime/dart/_internal.js
index bd7cd046a0d1..d8e517416d31 100644
--- a/pkg/dev_compiler/lib/runtime/dart/_internal.js
+++ b/pkg/dev_compiler/lib/runtime/dart/_internal.js
@@ -221,7 +221,7 @@ dart.library('dart/_internal', null, /* Imports */[
         let result = null;
         if (dart.notNull(growable)) {
           result = core.List$(E).new();
-          result.length = this.length;
+          result[dartx.length] = this.length;
         } else {
           result = core.List$(E).new(this.length);
         }
@@ -309,19 +309,19 @@ dart.library('dart/_internal', null, /* Imports */[
         }
       }
       get [_endIndex]() {
-        let length = this[_iterable].length;
+        let length = this[_iterable][dartx.length];
         if (this[_endOrLength] == null || dart.notNull(this[_endOrLength]) > dart.notNull(length))
           return length;
         return this[_endOrLength];
       }
       get [_startIndex]() {
-        let length = this[_iterable].length;
+        let length = this[_iterable][dartx.length];
         if (dart.notNull(this[_start]) > dart.notNull(length))
           return length;
         return this[_start];
       }
       get length() {
-        let length = this[_iterable].length;
+        let length = this[_iterable][dartx.length];
         if (dart.notNull(this[_start]) >= dart.notNull(length))
           return 0;
         if (this[_endOrLength] == null || dart.notNull(this[_endOrLength]) >= dart.notNull(length)) {
@@ -358,7 +358,7 @@ dart.library('dart/_internal', null, /* Imports */[
       toList(opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let start = this[_start];
-        let end = this[_iterable].length;
+        let end = this[_iterable][dartx.length];
         if (this[_endOrLength] != null && dart.notNull(this[_endOrLength]) < dart.notNull(end))
           end = this[_endOrLength];
         let length = dart.notNull(end) - dart.notNull(start);
@@ -366,12 +366,12 @@ dart.library('dart/_internal', null, /* Imports */[
           length = 0;
         let result = dart.notNull(growable) ? (() => {
           let _ = core.List$(E).new();
-          _.length = length;
+          _[dartx.length] = length;
           return _;
         })() : core.List$(E).new(length);
         for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           result[dartx.set](i, this[_iterable][dartx.elementAt](dart.notNull(start) + dart.notNull(i)));
-          if (dart.notNull(this[_iterable].length) < dart.notNull(end))
+          if (dart.notNull(this[_iterable][dartx.length]) < dart.notNull(end))
             throw new core.ConcurrentModificationError(this);
         }
         return dart.as(result, core.List$(E));
@@ -403,7 +403,7 @@ dart.library('dart/_internal', null, /* Imports */[
     class ListIterator extends core.Object {
       ListIterator(iterable) {
         this[_iterable] = iterable;
-        this[_length] = iterable.length;
+        this[_length] = iterable[dartx.length];
         this[_index] = 0;
         this[_current] = null;
       }
@@ -411,7 +411,7 @@ dart.library('dart/_internal', null, /* Imports */[
         return this[_current];
       }
       moveNext() {
-        let length = this[_iterable].length;
+        let length = this[_iterable][dartx.length];
         if (this[_length] != length) {
           throw new core.ConcurrentModificationError(this[_iterable]);
         }
@@ -455,7 +455,7 @@ dart.library('dart/_internal', null, /* Imports */[
         return new (MappedIterator$(S, T))(this[_iterable][dartx.iterator], this[_f]);
       }
       get length() {
-        return this[_iterable].length;
+        return this[_iterable][dartx.length];
       }
       get isEmpty() {
         return this[_iterable][dartx.isEmpty];
@@ -542,7 +542,7 @@ dart.library('dart/_internal', null, /* Imports */[
         super.ListIterable();
       }
       get length() {
-        return this[_source].length;
+        return this[_source][dartx.length];
       }
       elementAt(index) {
         return this[_f](this[_source][dartx.elementAt](index));
@@ -707,7 +707,7 @@ dart.library('dart/_internal', null, /* Imports */[
         super._(iterable, takeCount);
       }
       get length() {
-        let iterableLength = this[_iterable].length;
+        let iterableLength = this[_iterable][dartx.length];
         if (dart.notNull(iterableLength) > dart.notNull(this[_takeCount]))
           return this[_takeCount];
         return iterableLength;
@@ -845,7 +845,7 @@ dart.library('dart/_internal', null, /* Imports */[
         super._(iterable, skipCount);
       }
       get length() {
-        let length = dart.notNull(this[_iterable].length) - dart.notNull(this[_skipCount]);
+        let length = dart.notNull(this[_iterable][dartx.length]) - dart.notNull(this[_skipCount]);
         if (dart.notNull(length) >= 0)
           return length;
         return 0;
@@ -1169,20 +1169,20 @@ dart.library('dart/_internal', null, /* Imports */[
       static removeWhereList(list, test) {
         dart.as(test, dart.functionType(core.bool, [dart.bottom]));
         let retained = [];
-        let length = list.length;
+        let length = list[dartx.length];
         for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           let element = list[dartx.get](i);
           if (!dart.notNull(dart.dcall(test, element))) {
             retained[dartx.add](element);
           }
-          if (length != list.length) {
+          if (length != list[dartx.length]) {
             throw new core.ConcurrentModificationError(list);
           }
         }
-        if (retained.length == length)
+        if (retained[dartx.length] == length)
           return;
-        list.length = retained.length;
-        for (let i = 0; dart.notNull(i) < dart.notNull(retained.length); i = dart.notNull(i) + 1) {
+        list[dartx.length] = retained[dartx.length];
+        for (let i = 0; dart.notNull(i) < dart.notNull(retained[dartx.length]); i = dart.notNull(i) + 1) {
           list[dartx.set](i, retained[dartx.get](i));
         }
       }
@@ -1247,7 +1247,7 @@ dart.library('dart/_internal', null, /* Imports */[
       static lastWhereList(list, test, orElse) {
         dart.as(test, dart.functionType(core.bool, [dart.bottom]));
         dart.as(orElse, dart.functionType(core.Object, []));
-        for (let i = dart.notNull(list.length) - 1; dart.notNull(i) >= 0; i = dart.notNull(i) - 1) {
+        for (let i = dart.notNull(list[dartx.length]) - 1; dart.notNull(i) >= 0; i = dart.notNull(i) - 1) {
           let element = list[dartx.get](i);
           if (dart.notNull(dart.dcall(test, element)))
             return element;
@@ -1297,16 +1297,16 @@ dart.library('dart/_internal', null, /* Imports */[
           separator = null;
         if (dart.notNull(list[dartx.isEmpty]))
           return "";
-        if (list.length == 1)
+        if (list[dartx.length] == 1)
           return `${list[dartx.get](0)}`;
         let buffer = new core.StringBuffer();
         if (dart.notNull(separator[dartx.isEmpty])) {
-          for (let i = 0; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+          for (let i = 0; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
             buffer.write(list[dartx.get](i));
           }
         } else {
           buffer.write(list[dartx.get](0));
-          for (let i = 1; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+          for (let i = 1; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
             buffer.write(separator);
             buffer.write(list[dartx.get](i));
           }
@@ -1355,7 +1355,7 @@ dart.library('dart/_internal', null, /* Imports */[
       static shuffleList(list, random) {
         if (random == null)
           random = math.Random.new();
-        let length = list.length;
+        let length = list[dartx.length];
         while (dart.notNull(length) > 1) {
           let pos = random.nextInt(length);
           length = dart.notNull(length) - 1;
@@ -1365,15 +1365,15 @@ dart.library('dart/_internal', null, /* Imports */[
         }
       }
       static indexOfList(list, element, start) {
-        return Lists.indexOf(list, element, start, list.length);
+        return Lists.indexOf(list, element, start, list[dartx.length]);
       }
       static lastIndexOfList(list, element, start) {
         if (start == null)
-          start = dart.notNull(list.length) - 1;
+          start = dart.notNull(list[dartx.length]) - 1;
         return Lists.lastIndexOf(list, element, start);
       }
       static _rangeCheck(list, start, end) {
-        core.RangeError.checkValidRange(start, end, list.length);
+        core.RangeError.checkValidRange(start, end, list[dartx.length]);
       }
       getRangeList(list, start, end) {
         IterableMixinWorkaround$()._rangeCheck(list, start, end);
@@ -1395,7 +1395,7 @@ dart.library('dart/_internal', null, /* Imports */[
           otherList = from[dartx.skip](skipCount)[dartx.toList]({growable: false});
           otherStart = 0;
         }
-        if (dart.notNull(otherStart) + dart.notNull(length) > dart.notNull(otherList.length)) {
+        if (dart.notNull(otherStart) + dart.notNull(length) > dart.notNull(otherList[dartx.length])) {
           throw IterableElementError.tooFew();
         }
         Lists.copy(otherList, otherStart, list, start, length);
@@ -1406,21 +1406,21 @@ dart.library('dart/_internal', null, /* Imports */[
           iterable = iterable[dartx.toList]();
         }
         let removeLength = dart.notNull(end) - dart.notNull(start);
-        let insertLength = iterable.length;
+        let insertLength = iterable[dartx.length];
         if (dart.notNull(removeLength) >= dart.notNull(insertLength)) {
           let delta = dart.notNull(removeLength) - dart.notNull(insertLength);
           let insertEnd = dart.notNull(start) + dart.notNull(insertLength);
-          let newEnd = dart.notNull(list.length) - dart.notNull(delta);
+          let newEnd = dart.notNull(list[dartx.length]) - dart.notNull(delta);
           list[dartx.setRange](start, insertEnd, iterable);
           if (delta != 0) {
             list[dartx.setRange](insertEnd, newEnd, list, end);
-            list.length = newEnd;
+            list[dartx.length] = newEnd;
           }
         } else {
           let delta = dart.notNull(insertLength) - dart.notNull(removeLength);
-          let newLength = dart.notNull(list.length) + dart.notNull(delta);
+          let newLength = dart.notNull(list[dartx.length]) + dart.notNull(delta);
           let insertEnd = dart.notNull(start) + dart.notNull(insertLength);
-          list.length = newLength;
+          list[dartx.length] = newLength;
           list[dartx.setRange](insertEnd, newLength, list, end);
           list[dartx.setRange](start, insertEnd, iterable);
         }
@@ -1432,13 +1432,13 @@ dart.library('dart/_internal', null, /* Imports */[
         }
       }
       static insertAllList(list, index, iterable) {
-        core.RangeError.checkValueInInterval(index, 0, list.length, "index");
+        core.RangeError.checkValueInInterval(index, 0, list[dartx.length], "index");
         if (!dart.is(iterable, EfficientLength)) {
           iterable = iterable[dartx.toList]({growable: false});
         }
-        let insertionLength = iterable.length;
-        list.length = dart.notNull(list.length) + dart.notNull(insertionLength);
-        list[dartx.setRange](dart.notNull(index) + dart.notNull(insertionLength), list.length, list, index);
+        let insertionLength = iterable[dartx.length];
+        list[dartx.length] = dart.notNull(list[dartx.length]) + dart.notNull(insertionLength);
+        list[dartx.setRange](dart.notNull(index) + dart.notNull(insertionLength), list[dartx.length], list, index);
         for (let element of iterable) {
           list[dartx.set]((() => {
             let x = index;
@@ -1448,7 +1448,7 @@ dart.library('dart/_internal', null, /* Imports */[
         }
       }
       static setAllList(list, index, iterable) {
-        core.RangeError.checkValueInInterval(index, 0, list.length, "index");
+        core.RangeError.checkValueInInterval(index, 0, list[dartx.length], "index");
         for (let element of iterable) {
           list[dartx.set]((() => {
             let x = index;
@@ -1802,7 +1802,7 @@ dart.library('dart/_internal', null, /* Imports */[
       super.ListIterable();
     }
     get length() {
-      return this[_backedList].length;
+      return this[_backedList][dartx.length];
     }
     elementAt(index) {
       core.RangeError.checkValidIndex(index, this);
@@ -1824,7 +1824,7 @@ dart.library('dart/_internal', null, /* Imports */[
         return dart.notNull(this.containsKey(key)) ? this[_values][dartx.get](dart.as(key, core.int)) : null;
       }
       get length() {
-        return this[_values].length;
+        return this[_values][dartx.length];
       }
       get values() {
         return new (SubListIterable$(E))(this[_values], 0, null);
@@ -1846,10 +1846,10 @@ dart.library('dart/_internal', null, /* Imports */[
       }
       forEach(f) {
         dart.as(f, dart.functionType(dart.void, [core.int, E]));
-        let length = this[_values].length;
+        let length = this[_values][dartx.length];
         for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           f(i, this[_values][dartx.get](i));
-          if (length != this[_values].length) {
+          if (length != this[_values][dartx.length]) {
             throw new core.ConcurrentModificationError(this[_values]);
           }
         }
@@ -1901,10 +1901,10 @@ dart.library('dart/_internal', null, /* Imports */[
         super.ListIterable();
       }
       get length() {
-        return this[_source].length;
+        return this[_source][dartx.length];
       }
       elementAt(index) {
-        return this[_source][dartx.elementAt](dart.notNull(this[_source].length) - 1 - dart.notNull(index));
+        return this[_source][dartx.elementAt](dart.notNull(this[_source][dartx.length]) - 1 - dart.notNull(index));
       }
     }
     dart.setSignature(ReversedListIterable, {
@@ -1979,7 +1979,7 @@ dart.library('dart/_internal', null, /* Imports */[
         return true;
       if (!dart.is(b, core.List))
         return false;
-      let length = a.length;
+      let length = a[dartx.length];
       if (!dart.equals(length, dart.dload(b, 'length')))
         return false;
       for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
@@ -1989,7 +1989,7 @@ dart.library('dart/_internal', null, /* Imports */[
       return true;
     }
     static indexOf(a, element, startIndex, endIndex) {
-      if (dart.notNull(startIndex) >= dart.notNull(a.length)) {
+      if (dart.notNull(startIndex) >= dart.notNull(a[dartx.length])) {
         return -1;
       }
       if (dart.notNull(startIndex) < 0) {
@@ -2006,8 +2006,8 @@ dart.library('dart/_internal', null, /* Imports */[
       if (dart.notNull(startIndex) < 0) {
         return -1;
       }
-      if (dart.notNull(startIndex) >= dart.notNull(a.length)) {
-        startIndex = dart.notNull(a.length) - 1;
+      if (dart.notNull(startIndex) >= dart.notNull(a[dartx.length])) {
+        startIndex = dart.notNull(a[dartx.length]) - 1;
       }
       for (let i = startIndex; dart.notNull(i) >= 0; i = dart.notNull(i) - 1) {
         if (dart.equals(a[dartx.get](i), element)) {
@@ -2017,14 +2017,14 @@ dart.library('dart/_internal', null, /* Imports */[
       return -1;
     }
     static indicesCheck(a, start, end) {
-      core.RangeError.checkValidRange(start, end, a.length);
+      core.RangeError.checkValidRange(start, end, a[dartx.length]);
     }
     static rangeCheck(a, start, length) {
       core.RangeError.checkNotNegative(length);
       core.RangeError.checkNotNegative(start);
-      if (dart.notNull(start) + dart.notNull(length) > dart.notNull(a.length)) {
-        let message = `${start} + ${length} must be in the range [0..${a.length}]`;
-        throw new core.RangeError.range(length, 0, dart.notNull(a.length) - dart.notNull(start), "length", message);
+      if (dart.notNull(start) + dart.notNull(length) > dart.notNull(a[dartx.length])) {
+        let message = `${start} + ${length} must be in the range [0..${a[dartx.length]}]`;
+        throw new core.RangeError.range(length, 0, dart.notNull(a[dartx.length]) - dart.notNull(start), "length", message);
       }
     }
   }
@@ -2046,10 +2046,10 @@ dart.library('dart/_internal', null, /* Imports */[
   dart.fn(printToConsole, dart.void, [core.String]);
   class Sort extends core.Object {
     static sort(a, compare) {
-      Sort._doSort(a, 0, dart.notNull(a.length) - 1, compare);
+      Sort._doSort(a, 0, dart.notNull(a[dartx.length]) - 1, compare);
     }
     static sortRange(a, from, to, compare) {
-      if (dart.notNull(from) < 0 || dart.notNull(to) > dart.notNull(a.length) || dart.notNull(to) < dart.notNull(from)) {
+      if (dart.notNull(from) < 0 || dart.notNull(to) > dart.notNull(a[dartx.length]) || dart.notNull(to) < dart.notNull(from)) {
         throw "OutOfRange";
       }
       Sort._doSort(a, from, dart.notNull(to) - 1, compare);
diff --git a/pkg/dev_compiler/lib/runtime/dart/_isolate_helper.js b/pkg/dev_compiler/lib/runtime/dart/_isolate_helper.js
index 6ebc5e3bd62b..0bf4d57a206b 100644
--- a/pkg/dev_compiler/lib/runtime/dart/_isolate_helper.js
+++ b/pkg/dev_compiler/lib/runtime/dart/_isolate_helper.js
@@ -106,14 +106,14 @@ dart.library('dart/_isolate_helper', null, /* Imports */[
     }
     serializeArray(x) {
       let serialized = [];
-      serialized.length = x.length;
-      for (let i = 0; dart.notNull(i) < dart.notNull(x.length); i = dart.notNull(i) + 1) {
+      serialized[dartx.length] = x[dartx.length];
+      for (let i = 0; dart.notNull(i) < dart.notNull(x[dartx.length]); i = dart.notNull(i) + 1) {
         serialized[dartx.set](i, this.serialize(x[dartx.get](i)));
       }
       return serialized;
     }
     serializeArrayInPlace(x) {
-      for (let i = 0; dart.notNull(i) < dart.notNull(x.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(x[dartx.length]); i = dart.notNull(i) + 1) {
         x[dartx.set](i, this.serialize(x[dartx.get](i)));
       }
       return x;
@@ -128,8 +128,8 @@ dart.library('dart/_isolate_helper', null, /* Imports */[
       }
       let keys = dart.as(Object.keys(x), core.List);
       let values = [];
-      values.length = keys.length;
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      values[dartx.length] = keys[dartx.length];
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         values[dartx.set](i, this.serialize(x[keys[dartx.get](i)]));
       }
       return ['js-object', keys, values];
@@ -282,7 +282,7 @@ dart.library('dart/_isolate_helper', null, /* Imports */[
       return result;
     }
     deserializeArrayInPlace(x) {
-      for (let i = 0; dart.notNull(i) < dart.notNull(x.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(x[dartx.length]); i = dart.notNull(i) + 1) {
         x[dartx.set](i, this.deserialize(x[dartx.get](i)));
       }
       return x;
@@ -318,7 +318,7 @@ dart.library('dart/_isolate_helper', null, /* Imports */[
       let result = dart.map();
       this.deserializedObjects[dartx.add](result);
       keys = keys[dartx.map](dart.bind(this, 'deserialize'))[dartx.toList]();
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         result.set(keys[dartx.get](i), this.deserialize(values[dartx.get](i)));
       }
       return result;
@@ -355,7 +355,7 @@ dart.library('dart/_isolate_helper', null, /* Imports */[
       let values = dart.as(dart.dindex(x, 2), core.List);
       let o = {};
       this.deserializedObjects[dartx.add](o);
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         o[keys[dartx.get](i)] = this.deserialize(values[dartx.get](i));
       }
       return o;
diff --git a/pkg/dev_compiler/lib/runtime/dart/_js_helper.js b/pkg/dev_compiler/lib/runtime/dart/_js_helper.js
index 270c436b86c3..fd700b9de579 100644
--- a/pkg/dev_compiler/lib/runtime/dart/_js_helper.js
+++ b/pkg/dev_compiler/lib/runtime/dart/_js_helper.js
@@ -148,8 +148,8 @@ dart.library('dart/_js_helper', null, /* Imports */[
         start = 0;
       checkString(string);
       checkInt(start);
-      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]);
       }
       return new _AllMatchesIterable(this, string, start);
     }
@@ -167,16 +167,16 @@ dart.library('dart/_js_helper', null, /* Imports */[
       let match = dart.as(regexp.exec(string), core.List);
       if (match == null)
         return null;
-      if (match[dartx.get](dart.notNull(match.length) - 1) != null)
+      if (match[dartx.get](dart.notNull(match[dartx.length]) - 1) != null)
         return null;
-      match.length = dart.notNull(match.length) - 1;
+      match[dartx.length] = dart.notNull(match[dartx.length]) - 1;
       return new _MatchImplementation(this, dart.as(match, core.List$(core.String)));
     }
     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]);
       }
       return this[_execAnchored](string, start);
     }
@@ -218,7 +218,7 @@ dart.library('dart/_js_helper', null, /* Imports */[
       return this[_match].index;
     }
     get end() {
-      return dart.notNull(this.start) + dart.notNull(this[_match][dartx.get](0).length);
+      return dart.notNull(this.start) + dart.notNull(this[_match][dartx.get](0)[dartx.length]);
     }
     group(index) {
       return this[_match][dartx.get](index);
@@ -227,7 +227,7 @@ dart.library('dart/_js_helper', null, /* Imports */[
       return this.group(index);
     }
     get groupCount() {
-      return dart.notNull(this[_match].length) - 1;
+      return dart.notNull(this[_match][dartx.length]) - 1;
     }
     groups(groups) {
       let out = dart.list([], core.String);
@@ -280,7 +280,7 @@ dart.library('dart/_js_helper', null, /* Imports */[
     moveNext() {
       if (this[_string] == null)
         return false;
-      if (dart.notNull(this[_nextIndex]) <= dart.notNull(this[_string].length)) {
+      if (dart.notNull(this[_nextIndex]) <= dart.notNull(this[_string][dartx.length])) {
         let match = this[_regExp][_execGlobal](this[_string], this[_nextIndex]);
         if (match != null) {
           this[_current] = match;
@@ -313,7 +313,7 @@ dart.library('dart/_js_helper', null, /* Imports */[
       this.pattern = pattern;
     }
     get end() {
-      return dart.notNull(this.start) + dart.notNull(this.pattern.length);
+      return dart.notNull(this.start) + dart.notNull(this.pattern[dartx.length]);
     }
     get(g) {
       return this.group(g);
@@ -346,8 +346,8 @@ dart.library('dart/_js_helper', null, /* Imports */[
   });
   function allMatchesInStringUnchecked(needle, haystack, startIndex) {
     let result = core.List$(core.Match).new();
-    let length = haystack.length;
-    let patternLength = needle.length;
+    let length = haystack[dartx.length];
+    let patternLength = needle[dartx.length];
     while (true) {
       let position = haystack[dartx.indexOf](needle, startIndex);
       if (position == -1) {
@@ -599,7 +599,7 @@ dart.library('dart/_js_helper', null, /* Imports */[
               maxCharCode = 97 + dart.notNull(radix) - 10 - 1;
             }
             let digitsPart = dart.as(dart.dindex(match, digitsIndex), core.String);
-            for (let i = 0; dart.notNull(i) < dart.notNull(digitsPart.length); i = dart.notNull(i) + 1) {
+            for (let i = 0; dart.notNull(i) < dart.notNull(digitsPart[dartx.length]); i = dart.notNull(i) + 1) {
               let characterCode = dart.notNull(digitsPart[dartx.codeUnitAt](0)) | 32;
               if (dart.notNull(digitsPart[dartx.codeUnitAt](i)) > dart.notNull(maxCharCode)) {
                 return handleError(source);
@@ -672,7 +672,7 @@ dart.library('dart/_js_helper', null, /* Imports */[
     static _fromCharCodeApply(array) {
       let result = "";
       let kMaxApply = 500;
-      let end = array.length;
+      let end = array[dartx.length];
       for (let i = 0; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + dart.notNull(kMaxApply)) {
         let subarray = null;
         if (dart.notNull(end) <= dart.notNull(kMaxApply)) {
diff --git a/pkg/dev_compiler/lib/runtime/dart/_native_typed_data.js b/pkg/dev_compiler/lib/runtime/dart/_native_typed_data.js
index 4732d81b622d..d3c9ce03cc3a 100644
--- a/pkg/dev_compiler/lib/runtime/dart/_native_typed_data.js
+++ b/pkg/dev_compiler/lib/runtime/dart/_native_typed_data.js
@@ -158,8 +158,8 @@ dart.library('dart/_native_typed_data', null, /* Imports */[
       this[_storage] = storage;
     }
     _slowFromList(list) {
-      this[_storage] = NativeFloat32List.new(dart.notNull(list.length) * 4);
-      for (let i = 0; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+      this[_storage] = NativeFloat32List.new(dart.notNull(list[dartx.length]) * 4);
+      for (let i = 0; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
         let e = list[dartx.get](i);
         this[_storage].set(dart.notNull(i) * 4 + 0, e.x);
         this[_storage].set(dart.notNull(i) * 4 + 1, e.y);
@@ -266,8 +266,8 @@ dart.library('dart/_native_typed_data', null, /* Imports */[
       this[_storage] = storage;
     }
     _slowFromList(list) {
-      this[_storage] = NativeInt32List.new(dart.notNull(list.length) * 4);
-      for (let i = 0; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+      this[_storage] = NativeInt32List.new(dart.notNull(list[dartx.length]) * 4);
+      for (let i = 0; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
         let e = list[dartx.get](i);
         this[_storage].set(dart.notNull(i) * 4 + 0, e.x);
         this[_storage].set(dart.notNull(i) * 4 + 1, e.y);
@@ -374,8 +374,8 @@ dart.library('dart/_native_typed_data', null, /* Imports */[
       this[_storage] = storage;
     }
     _slowFromList(list) {
-      this[_storage] = NativeFloat64List.new(dart.notNull(list.length) * 2);
-      for (let i = 0; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+      this[_storage] = NativeFloat64List.new(dart.notNull(list[dartx.length]) * 2);
+      for (let i = 0; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
         let e = list[dartx.get](i);
         this[_storage].set(dart.notNull(i) * 2 + 0, e.x);
         this[_storage].set(dart.notNull(i) * 2 + 1, e.y);
@@ -533,8 +533,8 @@ dart.library('dart/_native_typed_data', null, /* Imports */[
   function _ensureNativeList(list) {
     if (dart.is(list, _interceptors.JSIndexable))
       return list;
-    let result = core.List.new(list.length);
-    for (let i = 0; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+    let result = core.List.new(list[dartx.length]);
+    for (let i = 0; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
       result[dartx.set](i, list[dartx.get](i));
     }
     return result;
diff --git a/pkg/dev_compiler/lib/runtime/dart/collection.js b/pkg/dev_compiler/lib/runtime/dart/collection.js
index 6c82e34c9247..18b09824737d 100644
--- a/pkg/dev_compiler/lib/runtime/dart/collection.js
+++ b/pkg/dev_compiler/lib/runtime/dart/collection.js
@@ -13,7 +13,7 @@ dart.library('dart/collection', null, /* Imports */[
         this[_source] = source;
       }
       get length() {
-        return this[_source].length;
+        return this[_source][dartx.length];
       }
       get(index) {
         return this[_source][dartx.elementAt](index);
@@ -192,7 +192,7 @@ dart.library('dart/collection', null, /* Imports */[
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let result = dart.notNull(growable) ? (() => {
           let _ = core.List$(E).new();
-          _.length = this.length;
+          _[dartx.length] = this.length;
           return _;
         })() : core.List$(E).new(this.length);
         let i = 0;
@@ -1066,7 +1066,7 @@ dart.library('dart/collection', null, /* Imports */[
         return dart.toString(buffer);
       }
       static _isToStringVisiting(o) {
-        for (let i = 0; dart.notNull(i) < dart.notNull(IterableBase$()._toStringVisiting.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(IterableBase$()._toStringVisiting[dartx.length]); i = dart.notNull(i) + 1) {
           if (dart.notNull(core.identical(o, IterableBase$()._toStringVisiting[dartx.get](i))))
             return true;
         }
@@ -1087,7 +1087,7 @@ dart.library('dart/collection', null, /* Imports */[
             return;
           let next = `${it.current}`;
           parts[dartx.add](next);
-          length = dart.notNull(length) + (dart.notNull(next.length) + dart.notNull(OVERHEAD));
+          length = dart.notNull(length) + (dart.notNull(next[dartx.length]) + dart.notNull(OVERHEAD));
           count = dart.notNull(count) + 1;
         }
         let penultimateString = null;
@@ -1109,7 +1109,7 @@ dart.library('dart/collection', null, /* Imports */[
             }
             ultimateString = `${penultimate}`;
             penultimateString = dart.as(parts[dartx.removeLast](), core.String);
-            length = dart.notNull(length) + (dart.notNull(ultimateString.length) + dart.notNull(OVERHEAD));
+            length = dart.notNull(length) + (dart.notNull(ultimateString[dartx.length]) + dart.notNull(OVERHEAD));
           } else {
             ultimate = it.current;
             count = dart.notNull(count) + 1;
@@ -1129,15 +1129,15 @@ dart.library('dart/collection', null, /* Imports */[
             }
             penultimateString = `${penultimate}`;
             ultimateString = `${ultimate}`;
-            length = dart.notNull(length) + (dart.notNull(ultimateString.length) + dart.notNull(penultimateString.length) + 2 * dart.notNull(OVERHEAD));
+            length = dart.notNull(length) + (dart.notNull(ultimateString[dartx.length]) + dart.notNull(penultimateString[dartx.length]) + 2 * dart.notNull(OVERHEAD));
           }
         }
         let elision = null;
-        if (dart.notNull(count) > dart.notNull(parts.length) + dart.notNull(TAIL_COUNT)) {
+        if (dart.notNull(count) > dart.notNull(parts[dartx.length]) + dart.notNull(TAIL_COUNT)) {
           elision = "...";
           length = dart.notNull(length) + (dart.notNull(ELLIPSIS_SIZE) + dart.notNull(OVERHEAD));
         }
-        while (dart.notNull(length) > dart.notNull(LENGTH_LIMIT) && dart.notNull(parts.length) > dart.notNull(HEAD_COUNT)) {
+        while (dart.notNull(length) > dart.notNull(LENGTH_LIMIT) && dart.notNull(parts[dartx.length]) > dart.notNull(HEAD_COUNT)) {
           length = dart.notNull(length) - dart.notNull(dart.as(dart.dsend(dart.dload(parts[dartx.removeLast](), 'length'), '+', OVERHEAD), core.int));
           if (elision == null) {
             elision = "...";
@@ -1639,25 +1639,25 @@ dart.library('dart/collection', null, /* Imports */[
         }
       }
       get isEmpty() {
-        return this.length == 0;
+        return this[dartx.length] == 0;
       }
       get isNotEmpty() {
         return !dart.notNull(this.isEmpty);
       }
       get first() {
-        if (this.length == 0)
+        if (this[dartx.length] == 0)
           throw _internal.IterableElementError.noElement();
         return this.get(0);
       }
       get last() {
-        if (this.length == 0)
+        if (this[dartx.length] == 0)
           throw _internal.IterableElementError.noElement();
-        return this.get(dart.notNull(this.length) - 1);
+        return this.get(dart.notNull(this[dartx.length]) - 1);
       }
       get single() {
-        if (this.length == 0)
+        if (this[dartx.length] == 0)
           throw _internal.IterableElementError.noElement();
-        if (dart.notNull(this.length) > 1)
+        if (dart.notNull(this[dartx.length]) > 1)
           throw _internal.IterableElementError.tooMany();
         return this.get(0);
       }
@@ -1755,7 +1755,7 @@ dart.library('dart/collection', null, /* Imports */[
       join(separator) {
         if (separator === void 0)
           separator = "";
-        if (this.length == 0)
+        if (this[dartx.length] == 0)
           return "";
         let buffer = new core.StringBuffer();
         buffer.writeAll(this, separator);
@@ -1818,18 +1818,18 @@ dart.library('dart/collection', null, /* Imports */[
         let result = null;
         if (dart.notNull(growable)) {
           result = core.List$(E).new();
-          result.length = this.length;
+          result[dartx.length] = this[dartx.length];
         } else {
-          result = core.List$(E).new(this.length);
+          result = core.List$(E).new(this[dartx.length]);
         }
-        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) {
           result[dartx.set](i, this.get(i));
         }
         return result;
       }
       toSet() {
         let result = core.Set$(E).new();
-        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) {
           result.add(this.get(i));
         }
         return result;
@@ -1873,30 +1873,30 @@ dart.library('dart/collection', null, /* Imports */[
       static _filter(source, test, retainMatching) {
         dart.as(test, dart.functionType(core.bool, [dart.bottom]));
         let retained = [];
-        let length = source.length;
+        let length = source[dartx.length];
         for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           let element = source[dartx.get](i);
           if (dart.dcall(test, element) == retainMatching) {
             retained[dartx.add](element);
           }
-          if (length != source.length) {
+          if (length != source[dartx.length]) {
             throw new core.ConcurrentModificationError(source);
           }
         }
-        if (retained.length != source.length) {
-          source[dartx.setRange](0, retained.length, retained);
-          source.length = retained.length;
+        if (retained[dartx.length] != source[dartx.length]) {
+          source[dartx.setRange](0, retained[dartx.length], retained);
+          source[dartx.length] = retained[dartx.length];
         }
       }
       clear() {
         this.length = 0;
       }
       removeLast() {
-        if (this.length == 0) {
+        if (this[dartx.length] == 0) {
           throw _internal.IterableElementError.noElement();
         }
-        let result = this.get(dart.notNull(this.length) - 1);
-        this.length = dart.notNull(this.length) - 1;
+        let result = this.get(dart.notNull(this[dartx.length]) - 1);
+        this[dartx.length] = dart.notNull(this[dartx.length]) - 1;
         return result;
       }
       sort(compare) {
@@ -1931,7 +1931,7 @@ dart.library('dart/collection', null, /* Imports */[
         core.RangeError.checkValidRange(start, end, listLength);
         let length = dart.notNull(end) - dart.notNull(start);
         let result = core.List$(E).new();
-        result.length = length;
+        result[dartx.length] = length;
         for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           result[dartx.set](i, this.get(dart.notNull(start) + dart.notNull(i)));
         }
@@ -1974,7 +1974,7 @@ dart.library('dart/collection', null, /* Imports */[
           otherList = iterable[dartx.skip](skipCount)[dartx.toList]({growable: false});
           otherStart = 0;
         }
-        if (dart.notNull(otherStart) + dart.notNull(length) > dart.notNull(otherList.length)) {
+        if (dart.notNull(otherStart) + dart.notNull(length) > dart.notNull(otherList[dartx.length])) {
           throw _internal.IterableElementError.tooFew();
         }
         if (dart.notNull(otherStart) < dart.notNull(start)) {
@@ -1994,7 +1994,7 @@ dart.library('dart/collection', null, /* Imports */[
           newContents = newContents[dartx.toList]();
         }
         let removeLength = dart.notNull(end) - dart.notNull(start);
-        let insertLength = newContents.length;
+        let insertLength = newContents[dartx.length];
         if (dart.notNull(removeLength) >= dart.notNull(insertLength)) {
           let delta = dart.notNull(removeLength) - dart.notNull(insertLength);
           let insertEnd = dart.notNull(start) + dart.notNull(insertLength);
@@ -2051,7 +2051,7 @@ dart.library('dart/collection', null, /* Imports */[
       }
       insert(index, element) {
         dart.as(element, E);
-        core.RangeError.checkValueInInterval(index, 0, this.length, "index");
+        core.RangeError.checkValueInInterval(index, 0, this[dartx.length], "index");
         if (index == this.length) {
           this.add(element);
           return;
@@ -2065,16 +2065,16 @@ dart.library('dart/collection', null, /* Imports */[
       removeAt(index) {
         let result = this.get(index);
         this.setRange(index, dart.notNull(this.length) - 1, this, dart.notNull(index) + 1);
-        this.length = dart.notNull(this.length) - 1;
+        this[dartx.length] = dart.notNull(this[dartx.length]) - 1;
         return result;
       }
       insertAll(index, iterable) {
         dart.as(iterable, core.Iterable$(E));
-        core.RangeError.checkValueInInterval(index, 0, this.length, "index");
+        core.RangeError.checkValueInInterval(index, 0, this[dartx.length], "index");
         if (dart.is(iterable, _internal.EfficientLength)) {
           iterable = iterable[dartx.toList]();
         }
-        let insertionLength = iterable.length;
+        let insertionLength = iterable[dartx.length];
         this.length = dart.notNull(this.length) + dart.notNull(insertionLength);
         this.setRange(dart.notNull(index) + dart.notNull(insertionLength), this.length, this, index);
         this.setAll(index, iterable);
@@ -2082,7 +2082,7 @@ dart.library('dart/collection', null, /* Imports */[
       setAll(index, iterable) {
         dart.as(iterable, core.Iterable$(E));
         if (dart.is(iterable, core.List)) {
-          this.setRange(index, dart.notNull(index) + dart.notNull(iterable.length), iterable);
+          this.setRange(index, dart.notNull(index) + dart.notNull(iterable[dartx.length]), iterable);
         } else {
           for (let element of iterable) {
             this.set((() => {
@@ -2249,7 +2249,7 @@ dart.library('dart/collection', null, /* Imports */[
         return this.keys[dartx.contains](key);
       }
       get length() {
-        return this.keys.length;
+        return this.keys[dartx.length];
       }
       get isEmpty() {
         return this.keys[dartx.isEmpty];
@@ -2515,7 +2515,7 @@ dart.library('dart/collection', null, /* Imports */[
       return map.keys[dartx.map](dart.fn(key => map.get(key)));
     }
     static length(map) {
-      return map.keys.length;
+      return map.keys[dartx.length];
     }
     static isEmpty(map) {
       return map.keys[dartx.isEmpty];
@@ -2931,9 +2931,9 @@ dart.library('dart/collection', null, /* Imports */[
       }
       static from(elements) {
         if (dart.is(elements, core.List)) {
-          let length = elements.length;
+          let length = elements[dartx.length];
           let queue = new (ListQueue$(E))(dart.notNull(length) + 1);
-          dart.assert(dart.notNull(queue[_table].length) > dart.notNull(length));
+          dart.assert(dart.notNull(queue[_table][dartx.length]) > dart.notNull(length));
           let sourceList = elements;
           queue[_table][dartx.setRange](0, length, dart.as(sourceList, core.Iterable$(E)), 0);
           queue[_tail] = length;
@@ -2941,7 +2941,7 @@ dart.library('dart/collection', null, /* Imports */[
         } else {
           let capacity = ListQueue$()._INITIAL_CAPACITY;
           if (dart.is(elements, _internal.EfficientLength)) {
-            capacity = elements.length;
+            capacity = elements[dartx.length];
           }
           let result = new (ListQueue$(E))(capacity);
           for (let element of dart.as(elements, core.Iterable$(E))) {
@@ -2956,7 +2956,7 @@ dart.library('dart/collection', null, /* Imports */[
       forEach(action) {
         dart.as(action, dart.functionType(dart.void, [E]));
         let modificationCount = this[_modificationCount];
-        for (let i = this[_head]; i != this[_tail]; i = dart.notNull(i) + 1 & dart.notNull(this[_table].length) - 1) {
+        for (let i = this[_head]; i != this[_tail]; i = dart.notNull(i) + 1 & dart.notNull(this[_table][dartx.length]) - 1) {
           action(this[_table][dartx.get](i));
           this[_checkModification](modificationCount);
         }
@@ -2965,7 +2965,7 @@ dart.library('dart/collection', null, /* Imports */[
         return this[_head] == this[_tail];
       }
       get length() {
-        return dart.notNull(this[_tail]) - dart.notNull(this[_head]) & dart.notNull(this[_table].length) - 1;
+        return dart.notNull(this[_tail]) - dart.notNull(this[_head]) & dart.notNull(this[_table][dartx.length]) - 1;
       }
       get first() {
         if (this[_head] == this[_tail])
@@ -2975,7 +2975,7 @@ dart.library('dart/collection', null, /* Imports */[
       get last() {
         if (this[_head] == this[_tail])
           throw _internal.IterableElementError.noElement();
-        return this[_table][dartx.get](dart.notNull(this[_tail]) - 1 & dart.notNull(this[_table].length) - 1);
+        return this[_table][dartx.get](dart.notNull(this[_tail]) - 1 & dart.notNull(this[_table][dartx.length]) - 1);
       }
       get single() {
         if (this[_head] == this[_tail])
@@ -2986,14 +2986,14 @@ dart.library('dart/collection', null, /* Imports */[
       }
       elementAt(index) {
         core.RangeError.checkValidIndex(index, this);
-        return this[_table][dartx.get](dart.notNull(this[_head]) + dart.notNull(index) & dart.notNull(this[_table].length) - 1);
+        return this[_table][dartx.get](dart.notNull(this[_head]) + dart.notNull(index) & dart.notNull(this[_table][dartx.length]) - 1);
       }
       toList(opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let list = null;
         if (dart.notNull(growable)) {
           list = core.List$(E).new();
-          list.length = this.length;
+          list[dartx.length] = this.length;
         } else {
           list = core.List$(E).new(this.length);
         }
@@ -3008,14 +3008,14 @@ dart.library('dart/collection', null, /* Imports */[
         dart.as(elements, core.Iterable$(E));
         if (dart.is(elements, core.List)) {
           let list = dart.as(elements, core.List);
-          let addCount = list.length;
+          let addCount = list[dartx.length];
           let length = this.length;
-          if (dart.notNull(length) + dart.notNull(addCount) >= dart.notNull(this[_table].length)) {
+          if (dart.notNull(length) + dart.notNull(addCount) >= dart.notNull(this[_table][dartx.length])) {
             this[_preGrow](dart.notNull(length) + dart.notNull(addCount));
             this[_table][dartx.setRange](length, dart.notNull(length) + dart.notNull(addCount), dart.as(list, core.Iterable$(E)), 0);
             this[_tail] = dart.notNull(this[_tail]) + dart.notNull(addCount);
           } else {
-            let endSpace = dart.notNull(this[_table].length) - dart.notNull(this[_tail]);
+            let endSpace = dart.notNull(this[_table][dartx.length]) - dart.notNull(this[_tail]);
             if (dart.notNull(addCount) < dart.notNull(endSpace)) {
               this[_table][dartx.setRange](this[_tail], dart.notNull(this[_tail]) + dart.notNull(addCount), dart.as(list, core.Iterable$(E)), 0);
               this[_tail] = dart.notNull(this[_tail]) + dart.notNull(addCount);
@@ -3033,7 +3033,7 @@ dart.library('dart/collection', null, /* Imports */[
         }
       }
       remove(object) {
-        for (let i = this[_head]; i != this[_tail]; i = dart.notNull(i) + 1 & dart.notNull(this[_table].length) - 1) {
+        for (let i = this[_head]; i != this[_tail]; i = dart.notNull(i) + 1 & dart.notNull(this[_table][dartx.length]) - 1) {
           let element = this[_table][dartx.get](i);
           if (dart.equals(element, object)) {
             this[_remove](i);
@@ -3056,7 +3056,7 @@ dart.library('dart/collection', null, /* Imports */[
             i = this[_remove](i);
             modificationCount = this[_modificationCount] = dart.notNull(this[_modificationCount]) + 1;
           } else {
-            i = dart.notNull(i) + 1 & dart.notNull(this[_table].length) - 1;
+            i = dart.notNull(i) + 1 & dart.notNull(this[_table][dartx.length]) - 1;
           }
         }
       }
@@ -3070,7 +3070,7 @@ dart.library('dart/collection', null, /* Imports */[
       }
       clear() {
         if (this[_head] != this[_tail]) {
-          for (let i = this[_head]; i != this[_tail]; i = dart.notNull(i) + 1 & dart.notNull(this[_table].length) - 1) {
+          for (let i = this[_head]; i != this[_tail]; i = dart.notNull(i) + 1 & dart.notNull(this[_table][dartx.length]) - 1) {
             this[_table][dartx.set](i, null);
           }
           this[_head] = this[_tail] = 0;
@@ -3086,7 +3086,7 @@ dart.library('dart/collection', null, /* Imports */[
       }
       addFirst(element) {
         dart.as(element, E);
-        this[_head] = dart.notNull(this[_head]) - 1 & dart.notNull(this[_table].length) - 1;
+        this[_head] = dart.notNull(this[_head]) - 1 & dart.notNull(this[_table][dartx.length]) - 1;
         this[_table][dartx.set](this[_head], element);
         if (this[_head] == this[_tail])
           this[_grow]();
@@ -3098,14 +3098,14 @@ dart.library('dart/collection', null, /* Imports */[
         this[_modificationCount] = dart.notNull(this[_modificationCount]) + 1;
         let result = this[_table][dartx.get](this[_head]);
         this[_table][dartx.set](this[_head], null);
-        this[_head] = dart.notNull(this[_head]) + 1 & dart.notNull(this[_table].length) - 1;
+        this[_head] = dart.notNull(this[_head]) + 1 & dart.notNull(this[_table][dartx.length]) - 1;
         return result;
       }
       removeLast() {
         if (this[_head] == this[_tail])
           throw _internal.IterableElementError.noElement();
         this[_modificationCount] = dart.notNull(this[_modificationCount]) + 1;
-        this[_tail] = dart.notNull(this[_tail]) - 1 & dart.notNull(this[_table].length) - 1;
+        this[_tail] = dart.notNull(this[_tail]) - 1 & dart.notNull(this[_table][dartx.length]) - 1;
         let result = this[_table][dartx.get](this[_tail]);
         this[_table][dartx.set](this[_tail], null);
         return result;
@@ -3131,13 +3131,13 @@ dart.library('dart/collection', null, /* Imports */[
       [_add](element) {
         dart.as(element, E);
         this[_table][dartx.set](this[_tail], element);
-        this[_tail] = dart.notNull(this[_tail]) + 1 & dart.notNull(this[_table].length) - 1;
+        this[_tail] = dart.notNull(this[_tail]) + 1 & dart.notNull(this[_table][dartx.length]) - 1;
         if (this[_head] == this[_tail])
           this[_grow]();
         this[_modificationCount] = dart.notNull(this[_modificationCount]) + 1;
       }
       [_remove](offset) {
-        let mask = dart.notNull(this[_table].length) - 1;
+        let mask = dart.notNull(this[_table][dartx.length]) - 1;
         let startDistance = dart.notNull(offset) - dart.notNull(this[_head]) & dart.notNull(mask);
         let endDistance = dart.notNull(this[_tail]) - dart.notNull(offset) & dart.notNull(mask);
         if (dart.notNull(startDistance) < dart.notNull(endDistance)) {
@@ -3163,23 +3163,23 @@ dart.library('dart/collection', null, /* Imports */[
         }
       }
       [_grow]() {
-        let newTable = core.List$(E).new(dart.notNull(this[_table].length) * 2);
-        let split = dart.notNull(this[_table].length) - dart.notNull(this[_head]);
+        let newTable = core.List$(E).new(dart.notNull(this[_table][dartx.length]) * 2);
+        let split = dart.notNull(this[_table][dartx.length]) - dart.notNull(this[_head]);
         newTable[dartx.setRange](0, split, this[_table], this[_head]);
         newTable[dartx.setRange](split, dart.notNull(split) + dart.notNull(this[_head]), this[_table], 0);
         this[_head] = 0;
-        this[_tail] = this[_table].length;
+        this[_tail] = this[_table][dartx.length];
         this[_table] = newTable;
       }
       [_writeToList](target) {
         dart.as(target, core.List$(E));
-        dart.assert(dart.notNull(target.length) >= dart.notNull(this.length));
+        dart.assert(dart.notNull(target[dartx.length]) >= dart.notNull(this.length));
         if (dart.notNull(this[_head]) <= dart.notNull(this[_tail])) {
           let length = dart.notNull(this[_tail]) - dart.notNull(this[_head]);
           target[dartx.setRange](0, length, this[_table], this[_head]);
           return length;
         } else {
-          let firstPartSize = dart.notNull(this[_table].length) - dart.notNull(this[_head]);
+          let firstPartSize = dart.notNull(this[_table][dartx.length]) - dart.notNull(this[_head]);
           target[dartx.setRange](0, firstPartSize, this[_table], this[_head]);
           target[dartx.setRange](firstPartSize, dart.notNull(firstPartSize) + dart.notNull(this[_tail]), this[_table], 0);
           return dart.notNull(this[_tail]) + dart.notNull(firstPartSize);
@@ -3266,7 +3266,7 @@ dart.library('dart/collection', null, /* Imports */[
           return false;
         }
         this[_current] = dart.as(this[_queue][_table][dartx.get](this[_position]), E);
-        this[_position] = dart.notNull(this[_position]) + 1 & dart.notNull(this[_queue][_table].length) - 1;
+        this[_position] = dart.notNull(this[_position]) + 1 & dart.notNull(this[_queue][_table][dartx.length]) - 1;
         return true;
       }
     }
@@ -4280,7 +4280,7 @@ dart.library('dart/collection', null, /* Imports */[
       forEach(action) {
         dart.as(action, dart.functionType(dart.void, [K, V]));
         let keys = this[_computeKeys]();
-        for (let i = 0, length = keys.length; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
+        for (let i = 0, length = keys[dartx.length]; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
           let key = keys[i];
           action(dart.as(key, K), this.get(key));
           if (keys !== this[_keys]) {
diff --git a/pkg/dev_compiler/lib/runtime/dart/convert.js b/pkg/dev_compiler/lib/runtime/dart/convert.js
index 530c1c2603ed..d18ed7446eef 100644
--- a/pkg/dev_compiler/lib/runtime/dart/convert.js
+++ b/pkg/dev_compiler/lib/runtime/dart/convert.js
@@ -134,7 +134,7 @@ dart.library('dart/convert', null, /* Imports */[
         start = 0;
       if (end === void 0)
         end = null;
-      let stringLength = string.length;
+      let stringLength = string[dartx.length];
       core.RangeError.checkValidRange(start, end, stringLength);
       if (end == null)
         end = stringLength;
@@ -177,7 +177,7 @@ dart.library('dart/convert', null, /* Imports */[
   });
   class StringConversionSinkMixin extends core.Object {
     add(str) {
-      return this.addSlice(str, 0, str.length, false);
+      return this.addSlice(str, 0, str[dartx.length], false);
     }
     asUtf8Sink(allowMalformed) {
       return new _Utf8ConversionSink(this, allowMalformed);
@@ -205,7 +205,7 @@ dart.library('dart/convert', null, /* Imports */[
       this[_sink].close();
     }
     addSlice(source, start, end, isLast) {
-      core.RangeError.checkValidRange(start, end, source.length);
+      core.RangeError.checkValidRange(start, end, source[dartx.length]);
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
         let codeUnit = source[dartx.codeUnitAt](i);
         if ((dart.notNull(codeUnit) & ~dart.notNull(this[_subsetMask])) != 0) {
@@ -237,7 +237,7 @@ dart.library('dart/convert', null, /* Imports */[
         start = 0;
       if (end === void 0)
         end = null;
-      let byteCount = bytes.length;
+      let byteCount = bytes[dartx.length];
       core.RangeError.checkValidRange(start, end, byteCount);
       if (end == null)
         end = byteCount;
@@ -356,10 +356,10 @@ dart.library('dart/convert', null, /* Imports */[
       this[_utf8Sink].close();
     }
     add(source) {
-      this.addSlice(source, 0, source.length, false);
+      this.addSlice(source, 0, source[dartx.length], false);
     }
     addSlice(source, start, end, isLast) {
-      core.RangeError.checkValidRange(start, end, source.length);
+      core.RangeError.checkValidRange(start, end, source[dartx.length]);
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
         if ((dart.notNull(source[dartx.get](i)) & ~dart.notNull(_ASCII_MASK)) != 0) {
           if (dart.notNull(i) > dart.notNull(start))
@@ -390,7 +390,7 @@ dart.library('dart/convert', null, /* Imports */[
       this[_sink].close();
     }
     add(source) {
-      for (let i = 0; dart.notNull(i) < dart.notNull(source.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(source[dartx.length]); i = dart.notNull(i) + 1) {
         if ((dart.notNull(source[dartx.get](i)) & ~dart.notNull(_ASCII_MASK)) != 0) {
           throw new core.FormatException("Source contains non-ASCII bytes.");
         }
@@ -398,7 +398,7 @@ dart.library('dart/convert', null, /* Imports */[
       this[_sink].add(core.String.fromCharCodes(source));
     }
     addSlice(source, start, end, isLast) {
-      let length = source.length;
+      let length = source[dartx.length];
       core.RangeError.checkValidRange(start, end, length);
       if (dart.notNull(start) < dart.notNull(end)) {
         if (start != 0 || end != length) {
@@ -445,16 +445,16 @@ dart.library('dart/convert', null, /* Imports */[
       this[_bufferIndex] = 0;
     }
     add(chunk) {
-      let freeCount = dart.notNull(this[_buffer].length) - dart.notNull(this[_bufferIndex]);
-      if (dart.notNull(chunk.length) > dart.notNull(freeCount)) {
-        let oldLength = this[_buffer].length;
-        let newLength = dart.notNull(_ByteCallbackSink._roundToPowerOf2(dart.notNull(chunk.length) + dart.notNull(oldLength))) * 2;
+      let freeCount = dart.notNull(this[_buffer][dartx.length]) - dart.notNull(this[_bufferIndex]);
+      if (dart.notNull(chunk[dartx.length]) > dart.notNull(freeCount)) {
+        let oldLength = this[_buffer][dartx.length];
+        let newLength = dart.notNull(_ByteCallbackSink._roundToPowerOf2(dart.notNull(chunk[dartx.length]) + dart.notNull(oldLength))) * 2;
         let grown = typed_data.Uint8List.new(newLength);
-        grown[dartx.setRange](0, this[_buffer].length, this[_buffer]);
+        grown[dartx.setRange](0, this[_buffer][dartx.length], this[_buffer]);
         this[_buffer] = grown;
       }
-      this[_buffer][dartx.setRange](this[_bufferIndex], dart.notNull(this[_bufferIndex]) + dart.notNull(chunk.length), chunk);
-      this[_bufferIndex] = dart.notNull(this[_bufferIndex]) + dart.notNull(chunk.length);
+      this[_buffer][dartx.setRange](this[_bufferIndex], dart.notNull(this[_bufferIndex]) + dart.notNull(chunk[dartx.length]), chunk);
+      this[_bufferIndex] = dart.notNull(this[_bufferIndex]) + dart.notNull(chunk[dartx.length]);
     }
     static _roundToPowerOf2(v) {
       dart.assert(dart.notNull(v) > 0);
@@ -673,7 +673,7 @@ dart.library('dart/convert', null, /* Imports */[
       super.Converter();
     }
     convert(text) {
-      let val = this[_convert](text, 0, text.length);
+      let val = this[_convert](text, 0, text[dartx.length]);
       return val == null ? text : val;
     }
     [_convert](text, start, end) {
@@ -931,7 +931,7 @@ dart.library('dart/convert', null, /* Imports */[
       if (dart.notNull(string[dartx.isEmpty]))
         return typed_data.Uint8List.new(0);
       checkAscii: {
-        for (let i = 0; dart.notNull(i) < dart.notNull(string.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(string[dartx.length]); i = dart.notNull(i) + 1) {
           if (dart.notNull(string[dartx.codeUnitAt](i)) >= 128)
             break checkAscii;
         }
@@ -950,16 +950,16 @@ dart.library('dart/convert', null, /* Imports */[
       };
       dart.fn(addChunk, dart.void, [typed_data.Uint8List, core.int, core.int]);
       _JsonUtf8Stringifier.stringify(object, this[_indent], dart.as(this[_toEncodable$], dart.functionType(core.Object, [core.Object])), this[_bufferSize], addChunk);
-      if (bytes.length == 1)
+      if (bytes[dartx.length] == 1)
         return bytes[dartx.get](0);
       let length = 0;
-      for (let i = 0; dart.notNull(i) < dart.notNull(bytes.length); i = dart.notNull(i) + 1) {
-        length = dart.notNull(length) + dart.notNull(bytes[dartx.get](i).length);
+      for (let i = 0; dart.notNull(i) < dart.notNull(bytes[dartx.length]); i = dart.notNull(i) + 1) {
+        length = dart.notNull(length) + dart.notNull(bytes[dartx.get](i)[dartx.length]);
       }
       let result = typed_data.Uint8List.new(length);
-      for (let i = 0, offset = 0; dart.notNull(i) < dart.notNull(bytes.length); i = dart.notNull(i) + 1) {
+      for (let i = 0, offset = 0; dart.notNull(i) < dart.notNull(bytes[dartx.length]); i = dart.notNull(i) + 1) {
         let byteList = bytes[dartx.get](i);
-        let end = dart.notNull(offset) + dart.notNull(byteList.length);
+        let end = dart.notNull(offset) + dart.notNull(byteList[dartx.length]);
         result.setRange(offset, end, byteList);
         offset = end;
       }
@@ -1115,7 +1115,7 @@ dart.library('dart/convert', null, /* Imports */[
     }
     writeStringContent(s) {
       let offset = 0;
-      let length = s.length;
+      let length = s[dartx.length];
       for (let i = 0; dart.notNull(i) < dart.notNull(length); i = dart.notNull(i) + 1) {
         let charCode = s[dartx.codeUnitAt](i);
         if (dart.notNull(charCode) > dart.notNull(_JsonStringifier.BACKSLASH))
@@ -1176,7 +1176,7 @@ dart.library('dart/convert', null, /* Imports */[
       }
     }
     [_checkCycle](object) {
-      for (let i = 0; dart.notNull(i) < dart.notNull(this[_seen].length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(this[_seen][dartx.length]); i = dart.notNull(i) + 1) {
         if (dart.notNull(core.identical(object, this[_seen][dartx.get](i)))) {
           throw new JsonCyclicError(object);
         }
@@ -1239,9 +1239,9 @@ dart.library('dart/convert', null, /* Imports */[
     }
     writeList(list) {
       this.writeString('[');
-      if (dart.notNull(list.length) > 0) {
+      if (dart.notNull(list[dartx.length]) > 0) {
         this.writeObject(list[dartx.get](0));
-        for (let i = 1; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+        for (let i = 1; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
           this.writeString(',');
           this.writeObject(list[dartx.get](i));
         }
@@ -1302,7 +1302,7 @@ dart.library('dart/convert', null, /* Imports */[
         this[_indentLevel] = dart.notNull(this[_indentLevel]) + 1;
         this.writeIndentation(this[_indentLevel]);
         this.writeObject(list[dartx.get](0));
-        for (let i = 1; dart.notNull(i) < dart.notNull(list.length); i = dart.notNull(i) + 1) {
+        for (let i = 1; dart.notNull(i) < dart.notNull(list[dartx.length]); i = dart.notNull(i) + 1) {
           this.writeString(',\n');
           this.writeIndentation(this[_indentLevel]);
           this.writeObject(list[dartx.get](i));
@@ -1434,14 +1434,14 @@ dart.library('dart/convert', null, /* Imports */[
       this.writeAsciiString(dart[dartx.toString](number));
     }
     writeAsciiString(string) {
-      for (let i = 0; dart.notNull(i) < dart.notNull(string.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(string[dartx.length]); i = dart.notNull(i) + 1) {
         let char = string[dartx.codeUnitAt](i);
         dart.assert(dart.notNull(char) <= 127);
         this.writeByte(char);
       }
     }
     writeString(string) {
-      this.writeStringSlice(string, 0, string.length);
+      this.writeStringSlice(string, 0, string[dartx.length]);
     }
     writeStringSlice(string, start, end) {
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
@@ -1527,7 +1527,7 @@ dart.library('dart/convert', null, /* Imports */[
     }
     writeIndentation(count) {
       let indent = this.indent;
-      let indentLength = indent.length;
+      let indentLength = indent[dartx.length];
       if (indentLength == 1) {
         let char = indent[dartx.get](0);
         while (dart.notNull(count) > 0) {
@@ -1627,7 +1627,7 @@ dart.library('dart/convert', null, /* Imports */[
       this[_sink].close();
     }
     add(source) {
-      this.addSlice(source, 0, source.length, false);
+      this.addSlice(source, 0, source[dartx.length], false);
     }
     [_addSliceToSink](source, start, end, isLast) {
       this[_sink].add(core.String.fromCharCodes(source, start, end));
@@ -1635,7 +1635,7 @@ dart.library('dart/convert', null, /* Imports */[
         this.close();
     }
     addSlice(source, start, end, isLast) {
-      core.RangeError.checkValidRange(start, end, source.length);
+      core.RangeError.checkValidRange(start, end, source[dartx.length]);
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
         let char = source[dartx.get](i);
         if (dart.notNull(char) > dart.notNull(_LATIN1_MASK) || dart.notNull(char) < 0) {
@@ -1663,7 +1663,7 @@ dart.library('dart/convert', null, /* Imports */[
       super._Latin1DecoderSink(sink);
     }
     addSlice(source, start, end, isLast) {
-      core.RangeError.checkValidRange(start, end, source.length);
+      core.RangeError.checkValidRange(start, end, source[dartx.length]);
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
         let char = source[dartx.get](i);
         if (dart.notNull(char) > dart.notNull(_LATIN1_MASK) || dart.notNull(char) < 0) {
@@ -1690,7 +1690,7 @@ dart.library('dart/convert', null, /* Imports */[
     }
     convert(data) {
       let lines = core.List$(core.String).new();
-      _LineSplitterSink._addSlice(data, 0, data.length, true, dart.bind(lines, dartx.add));
+      _LineSplitterSink._addSlice(data, 0, data[dartx.length], true, dart.bind(lines, dartx.add));
       return lines;
     }
     startChunkedConversion(sink) {
@@ -1717,7 +1717,7 @@ dart.library('dart/convert', null, /* Imports */[
       if (this[_carry] != null) {
         chunk = dart.notNull(this[_carry]) + dart.notNull(chunk[dartx.substring](start, end));
         start = 0;
-        end = chunk.length;
+        end = chunk[dartx.length];
         this[_carry] = null;
       }
       this[_carry] = _LineSplitterSink._addSlice(chunk, start, end, isLast, dart.bind(this[_sink], 'add'));
@@ -1915,7 +1915,7 @@ dart.library('dart/convert', null, /* Imports */[
     }
     close() {}
     addSlice(str, start, end, isLast) {
-      if (start != 0 || end != str.length) {
+      if (start != 0 || end != str[dartx.length]) {
         for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
           this[_stringSink].writeCharCode(str[dartx.codeUnitAt](i));
         }
@@ -1968,7 +1968,7 @@ dart.library('dart/convert', null, /* Imports */[
       return this[_sink].add(str);
     }
     addSlice(str, start, end, isLast) {
-      if (start == 0 && end == str.length) {
+      if (start == 0 && end == str[dartx.length]) {
         this.add(str);
       } else {
         this.add(str[dartx.substring](start, end));
@@ -2000,7 +2000,7 @@ dart.library('dart/convert', null, /* Imports */[
         this[_sink].close();
     }
     add(chunk) {
-      this.addSlice(chunk, 0, chunk.length, false);
+      this.addSlice(chunk, 0, chunk[dartx.length], false);
     }
     addSlice(codeUnits, startIndex, endIndex, isLast) {
       this[_decoder].convert(codeUnits, startIndex, endIndex);
@@ -2031,19 +2031,19 @@ dart.library('dart/convert', null, /* Imports */[
       if (dart.notNull(this[_buffer].isNotEmpty)) {
         let accumulated = dart.toString(this[_buffer]);
         this[_buffer].clear();
-        this[_chunkedSink].addSlice(accumulated, 0, accumulated.length, true);
+        this[_chunkedSink].addSlice(accumulated, 0, accumulated[dartx.length], true);
       } else {
         this[_chunkedSink].close();
       }
     }
     add(chunk) {
-      this.addSlice(chunk, 0, chunk.length, false);
+      this.addSlice(chunk, 0, chunk[dartx.length], false);
     }
     addSlice(chunk, startIndex, endIndex, isLast) {
       this[_decoder].convert(chunk, startIndex, endIndex);
       if (dart.notNull(this[_buffer].isNotEmpty)) {
         let accumulated = dart.toString(this[_buffer]);
-        this[_chunkedSink].addSlice(accumulated, 0, accumulated.length, isLast);
+        this[_chunkedSink].addSlice(accumulated, 0, accumulated[dartx.length], isLast);
         this[_buffer].clear();
         return;
       }
@@ -2104,7 +2104,7 @@ dart.library('dart/convert', null, /* Imports */[
         start = 0;
       if (end === void 0)
         end = null;
-      let stringLength = string.length;
+      let stringLength = string[dartx.length];
       core.RangeError.checkValidRange(start, end, stringLength);
       if (end == null)
         end = stringLength;
@@ -2205,7 +2205,7 @@ dart.library('dart/convert', null, /* Imports */[
       for (stringIndex = start; dart.notNull(stringIndex) < dart.notNull(end); stringIndex = dart.notNull(stringIndex) + 1) {
         let codeUnit = str[dartx.codeUnitAt](stringIndex);
         if (dart.notNull(codeUnit) <= dart.notNull(_ONE_BYTE_LIMIT)) {
-          if (dart.notNull(this[_bufferIndex]) >= dart.notNull(this[_buffer].length))
+          if (dart.notNull(this[_bufferIndex]) >= dart.notNull(this[_buffer][dartx.length]))
             break;
           this[_buffer][dartx.set]((() => {
             let x = this[_bufferIndex];
@@ -2213,7 +2213,7 @@ dart.library('dart/convert', null, /* Imports */[
             return x;
           })(), codeUnit);
         } else if (dart.notNull(_isLeadSurrogate(codeUnit))) {
-          if (dart.notNull(this[_bufferIndex]) + 3 >= dart.notNull(this[_buffer].length))
+          if (dart.notNull(this[_bufferIndex]) + 3 >= dart.notNull(this[_buffer][dartx.length]))
             break;
           let nextCodeUnit = str[dartx.codeUnitAt](dart.notNull(stringIndex) + 1);
           let wasCombined = this[_writeSurrogate](codeUnit, nextCodeUnit);
@@ -2223,7 +2223,7 @@ dart.library('dart/convert', null, /* Imports */[
         } else {
           let rune = codeUnit;
           if (dart.notNull(rune) <= dart.notNull(_TWO_BYTE_LIMIT)) {
-            if (dart.notNull(this[_bufferIndex]) + 1 >= dart.notNull(this[_buffer].length))
+            if (dart.notNull(this[_bufferIndex]) + 1 >= dart.notNull(this[_buffer][dartx.length]))
               break;
             this[_buffer][dartx.set]((() => {
               let x = this[_bufferIndex];
@@ -2237,7 +2237,7 @@ dart.library('dart/convert', null, /* Imports */[
             })(), 128 | dart.notNull(rune) & 63);
           } else {
             dart.assert(dart.notNull(rune) <= dart.notNull(_THREE_BYTE_LIMIT));
-            if (dart.notNull(this[_bufferIndex]) + 2 >= dart.notNull(this[_buffer].length))
+            if (dart.notNull(this[_bufferIndex]) + 2 >= dart.notNull(this[_buffer][dartx.length]))
               break;
             this[_buffer][dartx.set]((() => {
               let x = this[_bufferIndex];
@@ -2309,7 +2309,7 @@ dart.library('dart/convert', null, /* Imports */[
         start = this[_fillBuffer](str, start, end);
         let isLastSlice = dart.notNull(isLast) && start == end;
         if (start == dart.notNull(end) - 1 && dart.notNull(_isLeadSurrogate(str[dartx.codeUnitAt](start)))) {
-          if (dart.notNull(isLast) && dart.notNull(this[_bufferIndex]) < dart.notNull(this[_buffer].length) - 3) {
+          if (dart.notNull(isLast) && dart.notNull(this[_bufferIndex]) < dart.notNull(this[_buffer][dartx.length]) - 3) {
             let hasBeenCombined = this[_writeSurrogate](str[dartx.codeUnitAt](start), 0);
             dart.assert(!dart.notNull(hasBeenCombined));
           } else {
@@ -2342,7 +2342,7 @@ dart.library('dart/convert', null, /* Imports */[
         start = 0;
       if (end === void 0)
         end = null;
-      let length = codeUnits.length;
+      let length = codeUnits[dartx.length];
       core.RangeError.checkValidRange(start, end, length);
       if (end == null)
         end = length;
@@ -2580,7 +2580,7 @@ dart.library('dart/convert', null, /* Imports */[
       let map = new _JsonMap(e);
       let processed = map[_processed];
       let keys = map[_computeKeys]();
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         let key = keys[dartx.get](i);
         let revived = dart.dcall(reviver, key, walk(e[key]));
         processed[key] = revived;
@@ -2632,7 +2632,7 @@ dart.library('dart/convert', null, /* Imports */[
       }
     }
     get length() {
-      return dart.notNull(this[_isUpgraded]) ? this[_upgradedMap].length : this[_computeKeys]().length;
+      return dart.notNull(this[_isUpgraded]) ? this[_upgradedMap].length : this[_computeKeys]()[dartx.length];
     }
     get isEmpty() {
       return this.length == 0;
@@ -2673,7 +2673,7 @@ dart.library('dart/convert', null, /* Imports */[
       if (dart.notNull(this[_isUpgraded]))
         return this[_upgradedMap].containsValue(value);
       let keys = this[_computeKeys]();
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         let key = keys[dartx.get](i);
         if (dart.equals(this.get(key), value))
           return true;
@@ -2714,7 +2714,7 @@ dart.library('dart/convert', null, /* Imports */[
       if (dart.notNull(this[_isUpgraded]))
         return this[_upgradedMap].forEach(f);
       let keys = this[_computeKeys]();
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         let key = keys[dartx.get](i);
         let value = _JsonMap._getProperty(this[_processed], key);
         if (dart.notNull(_JsonMap._isUnprocessed(value))) {
@@ -2750,7 +2750,7 @@ dart.library('dart/convert', null, /* Imports */[
         return this[_upgradedMap];
       let result = dart.map();
       let keys = this[_computeKeys]();
-      for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(keys[dartx.length]); i = dart.notNull(i) + 1) {
         let key = keys[dartx.get](i);
         result.set(key, this.get(key));
       }
diff --git a/pkg/dev_compiler/lib/runtime/dart/core.js b/pkg/dev_compiler/lib/runtime/dart/core.js
index 9954c7ffecec..daddf3297142 100644
--- a/pkg/dev_compiler/lib/runtime/dart/core.js
+++ b/pkg/dev_compiler/lib/runtime/dart/core.js
@@ -888,7 +888,7 @@ dart.library('dart/core', null, /* Imports */[
       let sb = new StringBuffer();
       let i = 0;
       if (this[_arguments] != null) {
-        for (; dart.notNull(i) < dart.notNull(this[_arguments].length); i = dart.notNull(i) + 1) {
+        for (; dart.notNull(i) < dart.notNull(this[_arguments][dartx.length]); i = dart.notNull(i) + 1) {
           if (dart.notNull(i) > 0) {
             sb.write(", ");
           }
@@ -911,7 +911,7 @@ dart.library('dart/core', null, /* Imports */[
       } else {
         let actualParameters = dart.toString(sb);
         sb = new StringBuffer();
-        for (let i = 0; dart.notNull(i) < dart.notNull(this[_existingArgumentNames].length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(this[_existingArgumentNames][dartx.length]); i = dart.notNull(i) + 1) {
           if (dart.notNull(i) > 0) {
             sb.write(", ");
           }
@@ -1078,7 +1078,7 @@ dart.library('dart/core', null, /* Imports */[
       }
       if (offset == -1) {
         let source = dart.as(this.source, String);
-        if (dart.notNull(source.length) > 78) {
+        if (dart.notNull(source[dartx.length]) > 78) {
           source = dart.notNull(source[dartx.substring](0, 75)) + "...";
         }
         return `${report}\n${source}`;
@@ -1133,7 +1133,7 @@ dart.library('dart/core', null, /* Imports */[
         }
       }
       let slice = dart.as(dart.dsend(this.source, 'substring', start, end), String);
-      let markOffset = dart.notNull(offset) - dart.notNull(start) + dart.notNull(prefix.length);
+      let markOffset = dart.notNull(offset) - dart.notNull(start) + dart.notNull(prefix[dartx.length]);
       return `${report}${prefix}${slice}${postfix}\n${" "[dartx['*']](markOffset)}^\n`;
     }
   }
@@ -1415,7 +1415,7 @@ dart.library('dart/core', null, /* Imports */[
       static filled(length, fill) {
         let result = List$(E).new(length);
         if (length != 0 && fill != null) {
-          for (let i = 0; dart.notNull(i) < dart.notNull(result.length); i = dart.notNull(i) + 1) {
+          for (let i = 0; dart.notNull(i) < dart.notNull(result[dartx.length]); i = dart.notNull(i) + 1) {
             result[dartx.set](i, fill);
           }
         }
@@ -1436,7 +1436,7 @@ dart.library('dart/core', null, /* Imports */[
         let result = null;
         if (dart.notNull(growable)) {
           result = dart.list([], E);
-          result.length = length;
+          result[dartx.length] = length;
         } else {
           result = List$(E).new(length);
         }
@@ -1637,7 +1637,7 @@ dart.library('dart/core', null, /* Imports */[
         return String._stringFromIterable(charCodes, start, end);
       }
       let list = dart.as(charCodes, List);
-      let len = list.length;
+      let len = list[dartx.length];
       if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(len)) {
         throw new RangeError.range(start, 0, len);
       }
@@ -1660,9 +1660,9 @@ dart.library('dart/core', null, /* Imports */[
     }
     static _stringFromIterable(charCodes, start, end) {
       if (dart.notNull(start) < 0)
-        throw new RangeError.range(start, 0, charCodes.length);
+        throw new RangeError.range(start, 0, charCodes[dartx.length]);
       if (end != null && dart.notNull(end) < dart.notNull(start)) {
-        throw new RangeError.range(end, start, charCodes.length);
+        throw new RangeError.range(end, start, charCodes[dartx.length]);
       }
       let it = charCodes[dartx.iterator];
       for (let i = 0; dart.notNull(i) < dart.notNull(start); i = dart.notNull(i) + 1) {
@@ -1706,12 +1706,12 @@ dart.library('dart/core', null, /* Imports */[
           return new RuneIterator(this.string);
         }
         get last() {
-          if (this.string.length == 0) {
+          if (this.string[dartx.length] == 0) {
             throw new StateError('No elements.');
           }
-          let length = this.string.length;
+          let length = this.string[dartx.length];
           let code = this.string[dartx.codeUnitAt](dart.notNull(length) - 1);
-          if (dart.notNull(_isTrailSurrogate(code)) && dart.notNull(this.string.length) > 1) {
+          if (dart.notNull(_isTrailSurrogate(code)) && dart.notNull(this.string[dartx.length]) > 1) {
             let previousCode = this.string[dartx.codeUnitAt](dart.notNull(length) - 2);
             if (dart.notNull(_isLeadSurrogate(previousCode))) {
               return _combineSurrogatePair(previousCode, code);
@@ -1755,11 +1755,11 @@ dart.library('dart/core', null, /* Imports */[
       this[_position] = index;
       this[_nextPosition] = index;
       this[_currentCodePoint] = null;
-      RangeError.checkValueInInterval(index, 0, string.length);
+      RangeError.checkValueInInterval(index, 0, string[dartx.length]);
       this[_checkSplitSurrogate](index);
     }
     [_checkSplitSurrogate](index) {
-      if (dart.notNull(index) > 0 && dart.notNull(index) < dart.notNull(this.string.length) && dart.notNull(_isLeadSurrogate(this.string[dartx.codeUnitAt](dart.notNull(index) - 1))) && dart.notNull(_isTrailSurrogate(this.string[dartx.codeUnitAt](index)))) {
+      if (dart.notNull(index) > 0 && dart.notNull(index) < dart.notNull(this.string[dartx.length]) && dart.notNull(_isLeadSurrogate(this.string[dartx.codeUnitAt](dart.notNull(index) - 1))) && dart.notNull(_isTrailSurrogate(this.string[dartx.codeUnitAt](index)))) {
         throw new ArgumentError(`Index inside surrogate pair: ${index}`);
       }
     }
@@ -1774,7 +1774,7 @@ dart.library('dart/core', null, /* Imports */[
     reset(rawIndex) {
       if (rawIndex === void 0)
         rawIndex = 0;
-      RangeError.checkValueInInterval(rawIndex, 0, this.string.length, "rawIndex");
+      RangeError.checkValueInInterval(rawIndex, 0, this.string[dartx.length], "rawIndex");
       this[_checkSplitSurrogate](rawIndex);
       this[_position] = this[_nextPosition] = rawIndex;
       this[_currentCodePoint] = null;
@@ -1794,13 +1794,13 @@ dart.library('dart/core', null, /* Imports */[
     }
     moveNext() {
       this[_position] = this[_nextPosition];
-      if (this[_position] == this.string.length) {
+      if (this[_position] == this.string[dartx.length]) {
         this[_currentCodePoint] = null;
         return false;
       }
       let codeUnit = this.string[dartx.codeUnitAt](this[_position]);
       let nextPosition = dart.notNull(this[_position]) + 1;
-      if (dart.notNull(_isLeadSurrogate(codeUnit)) && dart.notNull(nextPosition) < dart.notNull(this.string.length)) {
+      if (dart.notNull(_isLeadSurrogate(codeUnit)) && dart.notNull(nextPosition) < dart.notNull(this.string[dartx.length])) {
         let nextCodeUnit = this.string[dartx.codeUnitAt](nextPosition);
         if (dart.notNull(_isTrailSurrogate(nextCodeUnit))) {
           this[_nextPosition] = dart.notNull(nextPosition) + 1;
@@ -1856,7 +1856,7 @@ dart.library('dart/core', null, /* Imports */[
       this[_contents] = `${content}`;
     }
     get length() {
-      return this[_contents].length;
+      return this[_contents][dartx.length];
     }
     get isEmpty() {
       return this.length == 0;
@@ -1956,7 +1956,7 @@ dart.library('dart/core', null, /* Imports */[
       if (this[_host] == null)
         return "";
       if (dart.notNull(this[_host][dartx.startsWith]('['))) {
-        return this[_host][dartx.substring](1, dart.notNull(this[_host].length) - 1);
+        return this[_host][dartx.substring](1, dart.notNull(this[_host][dartx.length]) - 1);
       }
       return this[_host];
     }
@@ -1998,7 +1998,7 @@ dart.library('dart/core', null, /* Imports */[
       let pathStart = 0;
       let char = EOI;
       let parseAuth = () => {
-        if (index == uri.length) {
+        if (index == uri[dartx.length]) {
           char = EOI;
           return;
         }
@@ -2006,7 +2006,7 @@ dart.library('dart/core', null, /* Imports */[
         let lastColon = -1;
         let lastAt = -1;
         char = uri[dartx.codeUnitAt](index);
-        while (dart.notNull(index) < dart.notNull(uri.length)) {
+        while (dart.notNull(index) < dart.notNull(uri[dartx.length])) {
           char = uri[dartx.codeUnitAt](index);
           if (char == Uri._SLASH || char == Uri._QUESTION || char == Uri._NUMBER_SIGN) {
             break;
@@ -2020,7 +2020,7 @@ dart.library('dart/core', null, /* Imports */[
             lastColon = -1;
             let endBracket = uri[dartx.indexOf](']', dart.notNull(index) + 1);
             if (endBracket == -1) {
-              index = uri.length;
+              index = uri[dartx.length];
               char = EOI;
               break;
             } else {
@@ -2052,7 +2052,7 @@ dart.library('dart/core', null, /* Imports */[
           hostEnd = lastColon;
         }
         host = Uri._makeHost(uri, hostStart, hostEnd, true);
-        if (dart.notNull(index) < dart.notNull(uri.length)) {
+        if (dart.notNull(index) < dart.notNull(uri[dartx.length])) {
           char = uri[dartx.codeUnitAt](index);
         }
       };
@@ -2062,7 +2062,7 @@ dart.library('dart/core', null, /* Imports */[
       let ALLOW_AUTH = 2;
       let state = NOT_IN_PATH;
       let i = index;
-      while (dart.notNull(i) < dart.notNull(uri.length)) {
+      while (dart.notNull(i) < dart.notNull(uri[dartx.length])) {
         char = uri[dartx.codeUnitAt](i);
         if (char == Uri._QUESTION || char == Uri._NUMBER_SIGN) {
           state = NOT_IN_PATH;
@@ -2078,7 +2078,7 @@ dart.library('dart/core', null, /* Imports */[
           scheme = Uri._makeScheme(uri, i);
           i = dart.notNull(i) + 1;
           pathStart = i;
-          if (i == uri.length) {
+          if (i == uri[dartx.length]) {
             char = EOI;
             state = NOT_IN_PATH;
           } else {
@@ -2100,7 +2100,7 @@ dart.library('dart/core', null, /* Imports */[
       if (state == ALLOW_AUTH) {
         dart.assert(char == Uri._SLASH);
         index = dart.notNull(index) + 1;
-        if (index == uri.length) {
+        if (index == uri[dartx.length]) {
           char = EOI;
           state = NOT_IN_PATH;
         } else {
@@ -2119,7 +2119,7 @@ dart.library('dart/core', null, /* Imports */[
       }
       dart.assert(state == IN_PATH || state == NOT_IN_PATH);
       if (state == IN_PATH) {
-        while ((index = dart.notNull(index) + 1) < dart.notNull(uri.length)) {
+        while ((index = dart.notNull(index) + 1) < dart.notNull(uri[dartx.length])) {
           char = uri[dartx.codeUnitAt](index);
           if (char == Uri._QUESTION || char == Uri._NUMBER_SIGN) {
             break;
@@ -2135,13 +2135,13 @@ dart.library('dart/core', null, /* Imports */[
       if (char == Uri._QUESTION) {
         let numberSignIndex = uri[dartx.indexOf]('#', dart.notNull(index) + 1);
         if (dart.notNull(numberSignIndex) < 0) {
-          query = Uri._makeQuery(uri, dart.notNull(index) + 1, uri.length, null);
+          query = Uri._makeQuery(uri, dart.notNull(index) + 1, uri[dartx.length], null);
         } else {
           query = Uri._makeQuery(uri, dart.notNull(index) + 1, numberSignIndex, null);
-          fragment = Uri._makeFragment(uri, dart.notNull(numberSignIndex) + 1, uri.length);
+          fragment = Uri._makeFragment(uri, dart.notNull(numberSignIndex) + 1, uri[dartx.length]);
         }
       } else if (char == Uri._NUMBER_SIGN) {
-        fragment = Uri._makeFragment(uri, dart.notNull(index) + 1, uri.length);
+        fragment = Uri._makeFragment(uri, dart.notNull(index) + 1, uri[dartx.length]);
       }
       return new Uri._internal(scheme, userinfo, host, port, path, query, fragment);
     }
@@ -2202,7 +2202,7 @@ dart.library('dart/core', null, /* Imports */[
       if (authority != null && dart.notNull(authority[dartx.isNotEmpty])) {
         let hostStart = 0;
         let hasUserInfo = false;
-        for (let i = 0; dart.notNull(i) < dart.notNull(authority.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(authority[dartx.length]); i = dart.notNull(i) + 1) {
           if (authority[dartx.codeUnitAt](i) == Uri._AT_SIGN) {
             hasUserInfo = true;
             userInfo = authority[dartx.substring](0, i);
@@ -2211,22 +2211,22 @@ dart.library('dart/core', null, /* Imports */[
           }
         }
         let hostEnd = hostStart;
-        if (dart.notNull(hostStart) < dart.notNull(authority.length) && authority[dartx.codeUnitAt](hostStart) == Uri._LEFT_BRACKET) {
-          for (; dart.notNull(hostEnd) < dart.notNull(authority.length); hostEnd = dart.notNull(hostEnd) + 1) {
+        if (dart.notNull(hostStart) < dart.notNull(authority[dartx.length]) && authority[dartx.codeUnitAt](hostStart) == Uri._LEFT_BRACKET) {
+          for (; dart.notNull(hostEnd) < dart.notNull(authority[dartx.length]); hostEnd = dart.notNull(hostEnd) + 1) {
             if (authority[dartx.codeUnitAt](hostEnd) == Uri._RIGHT_BRACKET)
               break;
           }
-          if (hostEnd == authority.length) {
+          if (hostEnd == authority[dartx.length]) {
             throw new FormatException("Invalid IPv6 host entry.", authority, hostStart);
           }
           Uri.parseIPv6Address(authority, dart.notNull(hostStart) + 1, hostEnd);
           hostEnd = dart.notNull(hostEnd) + 1;
-          if (hostEnd != authority.length && authority[dartx.codeUnitAt](hostEnd) != Uri._COLON) {
+          if (hostEnd != authority[dartx.length] && authority[dartx.codeUnitAt](hostEnd) != Uri._COLON) {
             throw new FormatException("Invalid end of authority", authority, hostEnd);
           }
         }
         let hasPort = false;
-        for (; dart.notNull(hostEnd) < dart.notNull(authority.length); hostEnd = dart.notNull(hostEnd) + 1) {
+        for (; dart.notNull(hostEnd) < dart.notNull(authority[dartx.length]); hostEnd = dart.notNull(hostEnd) + 1) {
           if (authority[dartx.codeUnitAt](hostEnd) == Uri._COLON) {
             let portString = authority[dartx.substring](dart.notNull(hostEnd) + 1);
             if (dart.notNull(portString[dartx.isNotEmpty]))
@@ -2300,7 +2300,7 @@ dart.library('dart/core', null, /* Imports */[
           path = `\\${path[dartx.substring](7)}`;
         } else {
           path = path[dartx.substring](4);
-          if (dart.notNull(path.length) < 3 || path[dartx.codeUnitAt](1) != Uri._COLON || path[dartx.codeUnitAt](2) != Uri._BACKSLASH) {
+          if (dart.notNull(path[dartx.length]) < 3 || path[dartx.codeUnitAt](1) != Uri._COLON || path[dartx.codeUnitAt](2) != Uri._BACKSLASH) {
             throw new ArgumentError("Windows paths with \\\\?\\ prefix must be absolute");
           }
         }
@@ -2308,17 +2308,17 @@ dart.library('dart/core', null, /* Imports */[
         path = path[dartx.replaceAll]("/", "\\");
       }
       let sep = "\\";
-      if (dart.notNull(path.length) > 1 && path[dartx.get](1) == ":") {
+      if (dart.notNull(path[dartx.length]) > 1 && path[dartx.get](1) == ":") {
         Uri._checkWindowsDriveLetter(path[dartx.codeUnitAt](0), true);
-        if (path.length == 2 || path[dartx.codeUnitAt](2) != Uri._BACKSLASH) {
+        if (path[dartx.length] == 2 || path[dartx.codeUnitAt](2) != Uri._BACKSLASH) {
           throw new ArgumentError("Windows paths with drive letter must be absolute");
         }
         let pathSegments = path[dartx.split](sep);
         Uri._checkWindowsPathReservedCharacters(pathSegments, true, 1);
         return Uri.new({scheme: "file", pathSegments: pathSegments});
       }
-      if (dart.notNull(path.length) > 0 && path[dartx.get](0) == sep) {
-        if (dart.notNull(path.length) > 1 && path[dartx.get](1) == sep) {
+      if (dart.notNull(path[dartx.length]) > 0 && path[dartx.get](0) == sep) {
+        if (dart.notNull(path[dartx.length]) > 1 && path[dartx.get](1) == sep) {
           let pathStart = path[dartx.indexOf]("\\", 2);
           let hostPart = pathStart == -1 ? path[dartx.substring](2) : path[dartx.substring](2, pathStart);
           let pathPart = pathStart == -1 ? "" : path[dartx.substring](dart.notNull(pathStart) + 1);
@@ -2348,14 +2348,14 @@ dart.library('dart/core', null, /* Imports */[
       let fragment = opts && 'fragment' in opts ? opts.fragment : null;
       let schemeChanged = false;
       if (scheme != null) {
-        scheme = Uri._makeScheme(scheme, scheme.length);
+        scheme = Uri._makeScheme(scheme, scheme[dartx.length]);
         schemeChanged = true;
       } else {
         scheme = this.scheme;
       }
       let isFile = scheme == "file";
       if (userInfo != null) {
-        userInfo = Uri._makeUserInfo(userInfo, 0, userInfo.length);
+        userInfo = Uri._makeUserInfo(userInfo, 0, userInfo[dartx.length]);
       } else {
         userInfo = this.userInfo;
       }
@@ -2368,7 +2368,7 @@ dart.library('dart/core', null, /* Imports */[
         }
       }
       if (host != null) {
-        host = Uri._makeHost(host, 0, host.length, false);
+        host = Uri._makeHost(host, 0, host[dartx.length], false);
       } else if (dart.notNull(this.hasAuthority)) {
         host = this.host;
       } else if (dart.notNull(userInfo[dartx.isNotEmpty]) || port != null || dart.notNull(isFile)) {
@@ -2389,7 +2389,7 @@ dart.library('dart/core', null, /* Imports */[
         query = this.query;
       }
       if (fragment != null) {
-        fragment = Uri._makeFragment(fragment, 0, fragment.length);
+        fragment = Uri._makeFragment(fragment, 0, fragment[dartx.length]);
       } else if (dart.notNull(this.hasFragment)) {
         fragment = this.fragment;
       }
@@ -2587,7 +2587,7 @@ dart.library('dart/core', null, /* Imports */[
       return Uri._normalize(fragment, start, end, dart.as(Uri._queryCharTable, List$(int)));
     }
     static _stringOrNullLength(s) {
-      return s == null ? 0 : s.length;
+      return s == null ? 0 : s[dartx.length];
     }
     static _isHexDigit(char) {
       if (dart.notNull(Uri._NINE) >= dart.notNull(char))
@@ -2604,7 +2604,7 @@ dart.library('dart/core', null, /* Imports */[
     }
     static _normalizeEscape(source, index, lowerCase) {
       dart.assert(source[dartx.codeUnitAt](index) == Uri._PERCENT);
-      if (dart.notNull(index) + 2 >= dart.notNull(source.length)) {
+      if (dart.notNull(index) + 2 >= dart.notNull(source[dartx.length])) {
         return "%";
       }
       let firstDigit = source[dartx.codeUnitAt](dart.notNull(index) + 1);
@@ -2748,7 +2748,7 @@ dart.library('dart/core', null, /* Imports */[
       return dart.notNull(base[dartx.substring](0, dart.notNull(baseEnd) + 1)) + dart.notNull(reference[dartx.substring](dart.notNull(refStart) - 3 * dart.notNull(backCount)));
     }
     [_hasDotSegments](path) {
-      if (dart.notNull(path.length) > 0 && path[dartx.codeUnitAt](0) == Uri._DOT)
+      if (dart.notNull(path[dartx.length]) > 0 && path[dartx.codeUnitAt](0) == Uri._DOT)
         return true;
       let index = path[dartx.indexOf]("/.");
       return index != -1;
@@ -2761,7 +2761,7 @@ dart.library('dart/core', null, /* Imports */[
       for (let segment of path[dartx.split]("/")) {
         appendSlash = false;
         if (segment == "..") {
-          if (!dart.notNull(output[dartx.isEmpty]) && (output.length != 1 || output[dartx.get](0) != ""))
+          if (!dart.notNull(output[dartx.isEmpty]) && (output[dartx.length] != 1 || output[dartx.get](0) != ""))
             output[dartx.removeLast]();
           appendSlash = true;
         } else if ("." == segment) {
@@ -2881,7 +2881,7 @@ dart.library('dart/core', null, /* Imports */[
     [_toWindowsFilePath]() {
       let hasDriveLetter = false;
       let segments = this.pathSegments;
-      if (dart.notNull(segments.length) > 0 && segments[dartx.get](0).length == 2 && segments[dartx.get](0)[dartx.codeUnitAt](1) == Uri._COLON) {
+      if (dart.notNull(segments[dartx.length]) > 0 && segments[dartx.get](0)[dartx.length] == 2 && segments[dartx.get](0)[dartx.codeUnitAt](1) == Uri._COLON) {
         Uri._checkWindowsDriveLetter(segments[dartx.get](0)[dartx.codeUnitAt](0), false);
         Uri._checkWindowsPathReservedCharacters(segments, false, 1);
         hasDriveLetter = true;
@@ -2897,7 +2897,7 @@ dart.library('dart/core', null, /* Imports */[
         result.write("\\");
       }
       result.writeAll(segments, "\\");
-      if (dart.notNull(hasDriveLetter) && segments.length == 1)
+      if (dart.notNull(hasDriveLetter) && segments[dartx.length] == 1)
         result.write("\\");
       return dart.toString(result);
     }
@@ -2997,7 +2997,7 @@ dart.library('dart/core', null, /* Imports */[
       };
       dart.fn(error, dart.void, [String]);
       let bytes = host[dartx.split]('.');
-      if (bytes.length != 4) {
+      if (bytes[dartx.length] != 4) {
         error('IPv4 address should contain exactly 4 parts');
       }
       return dart.as(bytes[dartx.map](dart.fn(byteString => {
@@ -3014,7 +3014,7 @@ dart.library('dart/core', null, /* Imports */[
       if (end === void 0)
         end = null;
       if (end == null)
-        end = host.length;
+        end = host[dartx.length];
       let error = (msg, position) => {
         if (position === void 0)
           position = null;
@@ -3032,7 +3032,7 @@ dart.library('dart/core', null, /* Imports */[
         return value;
       };
       dart.fn(parseHex, int, [int, int]);
-      if (dart.notNull(host.length) < 2)
+      if (dart.notNull(host[dartx.length]) < 2)
         error('address is too short');
       let parts = dart.list([], int);
       let wildcardSeen = false;
@@ -3058,7 +3058,7 @@ dart.library('dart/core', null, /* Imports */[
           partStart = dart.notNull(i) + 1;
         }
       }
-      if (parts.length == 0)
+      if (parts[dartx.length] == 0)
         error('too few parts');
       let atEnd = partStart == end;
       let isLastWildcard = parts[dartx.last] == -1;
@@ -3081,17 +3081,17 @@ dart.library('dart/core', null, /* Imports */[
 
       }
       if (dart.notNull(wildcardSeen)) {
-        if (dart.notNull(parts.length) > 7) {
+        if (dart.notNull(parts[dartx.length]) > 7) {
           error('an address with a wildcard must have less than 7 parts');
         }
-      } else if (parts.length != 8) {
+      } else if (parts[dartx.length] != 8) {
         error('an address without a wildcard must contain exactly 8 parts');
       }
       let bytes = List$(int).new(16);
-      for (let i = 0, index = 0; dart.notNull(i) < dart.notNull(parts.length); i = dart.notNull(i) + 1) {
+      for (let i = 0, index = 0; dart.notNull(i) < dart.notNull(parts[dartx.length]); i = dart.notNull(i) + 1) {
         let value = parts[dartx.get](i);
         if (value == -1) {
-          let wildCardLength = 9 - dart.notNull(parts.length);
+          let wildCardLength = 9 - dart.notNull(parts[dartx.length]);
           for (let j = 0; dart.notNull(j) < dart.notNull(wildCardLength); j = dart.notNull(j) + 1) {
             bytes[dartx.set](index, 0);
             bytes[dartx.set](dart.notNull(index) + 1, 0);
@@ -3116,7 +3116,7 @@ dart.library('dart/core', null, /* Imports */[
       dart.fn(byteToHex);
       let result = new StringBuffer();
       let bytes = encoding.encode(text);
-      for (let i = 0; dart.notNull(i) < dart.notNull(bytes.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(bytes[dartx.length]); i = dart.notNull(i) + 1) {
         let byte = bytes[dartx.get](i);
         if (dart.notNull(byte) < 128 && (dart.notNull(canonicalTable[dartx.get](dart.notNull(byte) >> 4)) & 1 << (dart.notNull(byte) & 15)) != 0) {
           result.writeCharCode(byte);
@@ -3150,7 +3150,7 @@ dart.library('dart/core', null, /* Imports */[
       let plusToSpace = opts && 'plusToSpace' in opts ? opts.plusToSpace : false;
       let encoding = opts && 'encoding' in opts ? opts.encoding : convert.UTF8;
       let simple = true;
-      for (let i = 0; dart.notNull(i) < dart.notNull(text.length) && dart.notNull(simple); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(text[dartx.length]) && dart.notNull(simple); i = dart.notNull(i) + 1) {
         let codeUnit = text[dartx.codeUnitAt](i);
         simple = codeUnit != Uri._PERCENT && codeUnit != Uri._PLUS;
       }
@@ -3163,13 +3163,13 @@ dart.library('dart/core', null, /* Imports */[
         }
       } else {
         bytes = List$(int).new();
-        for (let i = 0; dart.notNull(i) < dart.notNull(text.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(text[dartx.length]); i = dart.notNull(i) + 1) {
           let codeUnit = text[dartx.codeUnitAt](i);
           if (dart.notNull(codeUnit) > 127) {
             throw new ArgumentError("Illegal percent encoding in URI");
           }
           if (codeUnit == Uri._PERCENT) {
-            if (dart.notNull(i) + 3 > dart.notNull(text.length)) {
+            if (dart.notNull(i) + 3 > dart.notNull(text[dartx.length])) {
               throw new ArgumentError('Truncated URI');
             }
             bytes[dartx.add](Uri._hexCharPairToByte(text, dart.notNull(i) + 1));
diff --git a/pkg/dev_compiler/lib/runtime/dart/isolate.js b/pkg/dev_compiler/lib/runtime/dart/isolate.js
index dc371ad98979..e6ba40285cda 100644
--- a/pkg/dev_compiler/lib/runtime/dart/isolate.js
+++ b/pkg/dev_compiler/lib/runtime/dart/isolate.js
@@ -54,7 +54,7 @@ dart.library('dart/isolate', null, /* Imports */[
         throw new core.UnimplementedError("packageRoot");
       try {
         if (dart.is(args, core.List)) {
-          for (let i = 0; dart.notNull(i) < dart.notNull(args.length); i = dart.notNull(i) + 1) {
+          for (let i = 0; dart.notNull(i) < dart.notNull(args[dartx.length]); i = dart.notNull(i) + 1) {
             if (!(typeof args[dartx.get](i) == 'string')) {
               throw new core.ArgumentError(`Args must be a list of Strings ${args}`);
             }
diff --git a/pkg/dev_compiler/lib/src/codegen/js_codegen.dart b/pkg/dev_compiler/lib/src/codegen/js_codegen.dart
index d6f057584a7a..99ece9c88e0c 100644
--- a/pkg/dev_compiler/lib/src/codegen/js_codegen.dart
+++ b/pkg/dev_compiler/lib/src/codegen/js_codegen.dart
@@ -2676,8 +2676,7 @@ class JSCodegenVisitor extends GeneralizingAstVisitor {
 
     // Dart "extension" methods. Used for JS Array, Boolean, Number, String.
     if (allowExtensions && _extensionTypes.contains(type.element)) {
-      // Special case `length`. We can call it directly.
-      if (name != 'length') return js.call('dartx.#', _propertyName(name));
+      return js.call('dartx.#', _propertyName(name));
     }
 
     return _propertyName(name);
diff --git a/pkg/dev_compiler/test/codegen/expect/BenchmarkBase.js b/pkg/dev_compiler/test/codegen/expect/BenchmarkBase.js
index a395c7829f03..970537789042 100644
--- a/pkg/dev_compiler/test/codegen/expect/BenchmarkBase.js
+++ b/pkg/dev_compiler/test/codegen/expect/BenchmarkBase.js
@@ -10,10 +10,10 @@ dart.library('BenchmarkBase', null, /* Imports */[
       }
     }
     static listEquals(expected, actual) {
-      if (expected.length != actual.length) {
-        throw `Lists have different lengths: ${expected.length} vs ${actual.length}`;
+      if (expected[dartx.length] != actual[dartx.length]) {
+        throw `Lists have different lengths: ${expected[dartx.length]} vs ${actual[dartx.length]}`;
       }
-      for (let i = 0; dart.notNull(i) < dart.notNull(actual.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(actual[dartx.length]); i = dart.notNull(i) + 1) {
         Expect.equals(expected[dartx.get](i), actual[dartx.get](i));
       }
     }
diff --git a/pkg/dev_compiler/test/codegen/expect/DeltaBlue.js b/pkg/dev_compiler/test/codegen/expect/DeltaBlue.js
index cf3a6684b258..f528b619e12c 100644
--- a/pkg/dev_compiler/test/codegen/expect/DeltaBlue.js
+++ b/pkg/dev_compiler/test/codegen/expect/DeltaBlue.js
@@ -353,7 +353,7 @@ dart.library('DeltaBlue', null, /* Imports */[
       let unsatisfied = this.removePropagateFrom(out);
       let strength = REQUIRED;
       do {
-        for (let i = 0; dart.notNull(i) < dart.notNull(unsatisfied.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(unsatisfied[dartx.length]); i = dart.notNull(i) + 1) {
           let u = unsatisfied[dartx.get](i);
           if (dart.equals(u.strength, strength))
             this.incrementalAdd(u);
@@ -368,7 +368,7 @@ dart.library('DeltaBlue', null, /* Imports */[
       let mark = this.newMark();
       let plan = new Plan();
       let todo = sources;
-      while (dart.notNull(todo.length) > 0) {
+      while (dart.notNull(todo[dartx.length]) > 0) {
         let c = todo[dartx.removeLast]();
         if (c.output().mark != mark && dart.notNull(c.inputsKnown(mark))) {
           plan.addConstraint(c);
@@ -380,7 +380,7 @@ dart.library('DeltaBlue', null, /* Imports */[
     }
     extractPlanFromConstraints(constraints) {
       let sources = dart.list([], Constraint);
-      for (let i = 0; dart.notNull(i) < dart.notNull(constraints.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(constraints[dartx.length]); i = dart.notNull(i) + 1) {
         let c = constraints[dartx.get](i);
         if (dart.notNull(c.isInput()) && dart.notNull(c.isSatisfied()))
           sources[dartx.add](c);
@@ -389,7 +389,7 @@ dart.library('DeltaBlue', null, /* Imports */[
     }
     addPropagate(c, mark) {
       let todo = dart.list([c], Constraint);
-      while (dart.notNull(todo.length) > 0) {
+      while (dart.notNull(todo[dartx.length]) > 0) {
         let d = todo[dartx.removeLast]();
         if (d.output().mark == mark) {
           this.incrementalRemove(c);
@@ -406,15 +406,15 @@ dart.library('DeltaBlue', null, /* Imports */[
       out.stay = true;
       let unsatisfied = dart.list([], Constraint);
       let todo = dart.list([out], Variable);
-      while (dart.notNull(todo.length) > 0) {
+      while (dart.notNull(todo[dartx.length]) > 0) {
         let v = todo[dartx.removeLast]();
-        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints[dartx.length]); i = dart.notNull(i) + 1) {
           let c = v.constraints[dartx.get](i);
           if (!dart.notNull(c.isSatisfied()))
             unsatisfied[dartx.add](c);
         }
         let determining = v.determinedBy;
-        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); i = dart.notNull(i) + 1) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints[dartx.length]); i = dart.notNull(i) + 1) {
           let next = v.constraints[dartx.get](i);
           if (!dart.equals(next, determining) && dart.notNull(next.isSatisfied())) {
             next.recalculate();
@@ -426,7 +426,7 @@ dart.library('DeltaBlue', null, /* Imports */[
     }
     addConstraintsConsumingTo(v, coll) {
       let determining = v.determinedBy;
-      for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints[dartx.length]); i = dart.notNull(i) + 1) {
         let c = v.constraints[dartx.get](i);
         if (!dart.equals(c, determining) && dart.notNull(c.isSatisfied()))
           coll[dartx.add](c);
@@ -453,10 +453,10 @@ dart.library('DeltaBlue', null, /* Imports */[
       this.list[dartx.add](c);
     }
     size() {
-      return this.list.length;
+      return this.list[dartx.length];
     }
     execute() {
-      for (let i = 0; dart.notNull(i) < dart.notNull(this.list.length); i = dart.notNull(i) + 1) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(this.list[dartx.length]); i = dart.notNull(i) + 1) {
         this.list[dartx.get](i).execute();
       }
     }
diff --git a/pkg/dev_compiler/test/codegen/expect/cascade.js b/pkg/dev_compiler/test/codegen/expect/cascade.js
index ab5728a7916a..0a273d9eb6c8 100644
--- a/pkg/dev_compiler/test/codegen/expect/cascade.js
+++ b/pkg/dev_compiler/test/codegen/expect/cascade.js
@@ -50,7 +50,7 @@ dart.library('cascade', null, /* Imports */[
   dart.fn(test_mutate_outside_cascade, dart.void, []);
   function test_VariableDeclaration_single() {
     let a = [];
-    a.length = 2;
+    a[dartx.length] = 2;
     a[dartx.add](42);
     core.print(a);
   }
@@ -58,7 +58,7 @@ dart.library('cascade', null, /* Imports */[
   function test_VariableDeclaration_last() {
     let a = 42, b = (() => {
       let _ = [];
-      _.length = 2;
+      _[dartx.length] = 2;
       _[dartx.add](a);
       return _;
     })();
@@ -68,7 +68,7 @@ dart.library('cascade', null, /* Imports */[
   function test_VariableDeclaration_first() {
     let a = (() => {
       let _ = [];
-      _.length = 2;
+      _[dartx.length] = 2;
       _[dartx.add](3);
       return _;
     })(), b = 2;