Make int and double nullable by default

test/codegen/expect/dart/core.js

 var core;
 (function(exports) {
   'use strict';
   // Function _symbolToString: (Symbol) → String
   function _symbolToString(symbol) {
     return _internal.Symbol.getName(dart.as(symbol, _internal.Symbol));
   }
   // Function _symbolMapToStringMap: (Map<Symbol, dynamic>) → dynamic
   function _symbolMapToStringMap(map) {
     if (map === null)
@@ skipping 102 matching lines @@
             return 0.0;
           return double.parse(matched);
         }
         let years = int.parse(match.get(1));
         let month = int.parse(match.get(2));
         let day = int.parse(match.get(3));
         let hour = parseIntOrZero(match.get(4));
         let minute = parseIntOrZero(match.get(5));
         let second = parseIntOrZero(match.get(6));
         let addOneMillisecond = false;
-        let millisecond = (parseDoubleOrZero(match.get(7)) * 1000).round();
+        let millisecond = (dart.notNull(parseDoubleOrZero(match.get(7))) * 1000).round();
         if (millisecond === 1000) {
           addOneMillisecond = true;
           millisecond = 999;
         }
         let isUtc = false;
         if (match.get(8) !== null) {
           isUtc = true;
           if (match.get(9) !== null) {
             let sign = dart.equals(match.get(9), '-') ? -1 : 1;
             let hourDifference = int.parse(match.get(10));
             let minuteDifference = parseIntOrZero(match.get(11));
-            minuteDifference = 60 * hourDifference;
-            minute = sign * minuteDifference;
+            minuteDifference = 60 * dart.notNull(hourDifference);
+            minute = dart.notNull(sign) * dart.notNull(minuteDifference);
           }
         }
         let millisecondsSinceEpoch = _brokenDownDateToMillisecondsSinceEpoch(years, month, day, hour, minute, second, millisecond, isUtc);
         if (millisecondsSinceEpoch === null) {
           throw new FormatException("Time out of range", formattedString);
         }
         if (addOneMillisecond)
-          millisecondsSinceEpoch++;
+          dart.notNull(millisecondsSinceEpoch)++;
         return new DateTime.fromMillisecondsSinceEpoch(millisecondsSinceEpoch, {isUtc: isUtc});
       } else {
         throw new FormatException("Invalid date format", formattedString);
       }
     }
     DateTime$fromMillisecondsSinceEpoch(millisecondsSinceEpoch, opt$) {
       let isUtc = opt$.isUtc === void 0 ? false : opt$.isUtc;
       this.millisecondsSinceEpoch = millisecondsSinceEpoch;
       this.isUtc = isUtc;
-      if (millisecondsSinceEpoch.abs() > _MAX_MILLISECONDS_SINCE_EPOCH) {
+      if (dart.notNull(millisecondsSinceEpoch.abs()) > dart.notNull(_MAX_MILLISECONDS_SINCE_EPOCH)) {
         throw new ArgumentError(millisecondsSinceEpoch);
       }
       if (isUtc === null)
         throw new ArgumentError(isUtc);
     }
     ['=='](other) {
       if (!dart.notNull(dart.is(other, DateTime)))
         return false;
-      return dart.notNull(this.millisecondsSinceEpoch === dart.dload(other, 'millisecondsSinceEpoch')) && dart.notNull(this.isUtc === dart.dload(other, 'isUtc'));
+      return this.millisecondsSinceEpoch === dart.dload(other, 'millisecondsSinceEpoch') && this.isUtc === dart.dload(other, 'isUtc');
     }
     isBefore(other) {
-      return this.millisecondsSinceEpoch < other.millisecondsSinceEpoch;
+      return dart.notNull(this.millisecondsSinceEpoch) < dart.notNull(other.millisecondsSinceEpoch);
     }
     isAfter(other) {
-      return this.millisecondsSinceEpoch > other.millisecondsSinceEpoch;
+      return dart.notNull(this.millisecondsSinceEpoch) > dart.notNull(other.millisecondsSinceEpoch);
     }
     isAtSameMomentAs(other) {
       return this.millisecondsSinceEpoch === other.millisecondsSinceEpoch;
     }
     compareTo(other) {
       return this.millisecondsSinceEpoch.compareTo(other.millisecondsSinceEpoch);
     }
     get hashCode() {
       return this.millisecondsSinceEpoch;
     }
     toLocal() {
       if (this.isUtc) {
         return new DateTime.fromMillisecondsSinceEpoch(this.millisecondsSinceEpoch, {isUtc: false});
       }
       return this;
     }
     toUtc() {
       if (this.isUtc)
         return this;
       return new DateTime.fromMillisecondsSinceEpoch(this.millisecondsSinceEpoch, {isUtc: true});
     }
     static [_fourDigits](n) {
       let absN = n.abs();
-      let sign = n < 0 ? "-" : "";
-      if (absN >= 1000)
+      let sign = dart.notNull(n) < 0 ? "-" : "";
+      if (dart.notNull(absN) >= 1000)
         return `${n}`;
-      if (absN >= 100)
+      if (dart.notNull(absN) >= 100)
         return `${sign}0${absN}`;
-      if (absN >= 10)
+      if (dart.notNull(absN) >= 10)
         return `${sign}00${absN}`;
       return `${sign}000${absN}`;
     }
     static [_sixDigits](n) {
-      dart.assert(dart.notNull(n < -9999) || dart.notNull(n > 9999));
+      dart.assert(dart.notNull(n) < -9999 || dart.notNull(n) > 9999);
       let absN = n.abs();
-      let sign = n < 0 ? "-" : "+";
-      if (absN >= 100000)
+      let sign = dart.notNull(n) < 0 ? "-" : "+";
+      if (dart.notNull(absN) >= 100000)
         return `${sign}${absN}`;
       return `${sign}0${absN}`;
     }
     static [_threeDigits](n) {
-      if (n >= 100)
+      if (dart.notNull(n) >= 100)
         return `${n}`;
-      if (n >= 10)
+      if (dart.notNull(n) >= 10)
         return `0${n}`;
       return `00${n}`;
     }
     static [_twoDigits](n) {
-      if (n >= 10)
+      if (dart.notNull(n) >= 10)
         return `${n}`;
       return `0${n}`;
     }
     toString() {
       let y = _fourDigits(this.year);
       let m = _twoDigits(this.month);
       let d = _twoDigits(this.day);
       let h = _twoDigits(this.hour);
       let min = _twoDigits(this.minute);
       let sec = _twoDigits(this.second);
       let ms = _threeDigits(this.millisecond);
       if (this.isUtc) {
         return `${y}-${m}-${d} ${h}:${min}:${sec}.${ms}Z`;
       } else {
         return `${y}-${m}-${d} ${h}:${min}:${sec}.${ms}`;
       }
     }
     toIso8601String() {
-      let y = dart.notNull(this.year >= -9999) && dart.notNull(this.year <= 9999) ? _fourDigits(this.year) : _sixDigits(this.year);
+      let y = dart.notNull(this.year) >= -9999 && dart.notNull(this.year) <= 9999 ? _fourDigits(this.year) : _sixDigits(this.year);
       let m = _twoDigits(this.month);
       let d = _twoDigits(this.day);
       let h = _twoDigits(this.hour);
       let min = _twoDigits(this.minute);
       let sec = _twoDigits(this.second);
       let ms = _threeDigits(this.millisecond);
       if (this.isUtc) {
         return `${y}-${m}-${d}T${h}:${min}:${sec}.${ms}Z`;
       } else {
         return `${y}-${m}-${d}T${h}:${min}:${sec}.${ms}`;
       }
     }
     add(duration) {
       let ms = this.millisecondsSinceEpoch;
-      return new DateTime.fromMillisecondsSinceEpoch(ms + duration.inMilliseconds, {isUtc: this.isUtc});
+      return new DateTime.fromMillisecondsSinceEpoch(dart.notNull(ms) + dart.notNull(duration.inMilliseconds), {isUtc: this.isUtc});
     }
     subtract(duration) {
       let ms = this.millisecondsSinceEpoch;
-      return new DateTime.fromMillisecondsSinceEpoch(ms - duration.inMilliseconds, {isUtc: this.isUtc});
+      return new DateTime.fromMillisecondsSinceEpoch(dart.notNull(ms) - dart.notNull(duration.inMilliseconds), {isUtc: this.isUtc});
     }
     difference(other) {
       let ms = this.millisecondsSinceEpoch;
       let otherMs = other.millisecondsSinceEpoch;
-      return new Duration({milliseconds: ms - otherMs});
+      return new Duration({milliseconds: dart.notNull(ms) - dart.notNull(otherMs)});
     }
     DateTime$_internal(year, month, day, hour, minute, second, millisecond, isUtc) {
       this.isUtc = dart.as(typeof isUtc == boolean ? isUtc : dart.throw_(new ArgumentError(isUtc)), bool);
       this.millisecondsSinceEpoch = dart.as(_js_helper.checkInt(_js_helper.Primitives.valueFromDecomposedDate(year, month, day, hour, minute, second, millisecond, isUtc)), int);
     }
     DateTime$_now() {
       this.isUtc = false;
-      this.millisecondsSinceEpoch = dart.notNull(_js_helper.Primitives.dateNow());
+      this.millisecondsSinceEpoch = _js_helper.Primitives.dateNow();
     }
     static [_brokenDownDateToMillisecondsSinceEpoch](year, month, day, hour, minute, second, millisecond, isUtc) {
       return dart.as(_js_helper.Primitives.valueFromDecomposedDate(year, month, day, hour, minute, second, millisecond, isUtc), int);
     }
     get timeZoneName() {
       if (this.isUtc)
         return "UTC";
       return _js_helper.Primitives.getTimeZoneName(this);
     }
     get timeZoneOffset() {
@@ skipping 55 matching lines @@
   DateTime._MAX_MILLISECONDS_SINCE_EPOCH = 8640000000000000;
   class double extends num {
     static parse(source, onError) {
       if (onError === void 0)
         onError = null;
       return _js_helper.Primitives.parseDouble(source, onError);
     }
   }
   double.NAN = 0.0 / 0.0;
   double.INFINITY = 1.0 / 0.0;
-  double.NEGATIVE_INFINITY = -INFINITY;
+  double.NEGATIVE_INFINITY = -dart.notNull(INFINITY);
   double.MIN_POSITIVE = 5e-324;
   double.MAX_FINITE = 1.7976931348623157e+308;
   let _duration = Symbol('_duration');
   class Duration extends dart.Object {
     Duration(opt$) {
       let days = opt$.days === void 0 ? 0 : opt$.days;
       let hours = opt$.hours === void 0 ? 0 : opt$.hours;
       let minutes = opt$.minutes === void 0 ? 0 : opt$.minutes;
       let seconds = opt$.seconds === void 0 ? 0 : opt$.seconds;
       let milliseconds = opt$.milliseconds === void 0 ? 0 : opt$.milliseconds;
       let microseconds = opt$.microseconds === void 0 ? 0 : opt$.microseconds;
-      this.Duration$_microseconds(days * MICROSECONDS_PER_DAY + hours * MICROSECONDS_PER_HOUR + minutes * MICROSECONDS_PER_MINUTE + seconds * MICROSECONDS_PER_SECOND + milliseconds * MICROSECONDS_PER_MILLISECOND + microseconds);
+      this.Duration$_microseconds(dart.notNull(days) * dart.notNull(MICROSECONDS_PER_DAY) + dart.notNull(hours) * dart.notNull(MICROSECONDS_PER_HOUR) + dart.notNull(minutes) * dart.notNull(MICROSECONDS_PER_MINUTE) + dart.notNull(seconds) * dart.notNull(MICROSECONDS_PER_SECOND) + dart.notNull(milliseconds) * dart.notNull(MICROSECONDS_PER_MILLISECOND) + dart.notNull(microseconds));
     }
     Duration$_microseconds($_duration) {
       this[_duration] = $_duration;
     }
     ['+'](other) {
-      return new Duration._microseconds(this[_duration] + other[_duration]);
+      return new Duration._microseconds(dart.notNull(this[_duration]) + dart.notNull(other[_duration]));
     }
     ['-'](other) {
-      return new Duration._microseconds(this[_duration] - other[_duration]);
+      return new Duration._microseconds(dart.notNull(this[_duration]) - dart.notNull(other[_duration]));
     }
     ['*'](factor) {
-      return new Duration._microseconds((this[_duration] * dart.notNull(factor)).round());
+      return new Duration._microseconds((dart.notNull(this[_duration]) * dart.notNull(factor)).round());
     }
     ['~/'](quotient) {
       if (quotient === 0)
         throw new IntegerDivisionByZeroException();
-      return new Duration._microseconds((this[_duration] / quotient).truncate());
+      return new Duration._microseconds((dart.notNull(this[_duration]) / dart.notNull(quotient)).truncate());
     }
     ['<'](other) {
-      return this[_duration] < other[_duration];
+      return dart.notNull(this[_duration]) < dart.notNull(other[_duration]);
     }
     ['>'](other) {
-      return this[_duration] > other[_duration];
+      return dart.notNull(this[_duration]) > dart.notNull(other[_duration]);
     }
     ['<='](other) {
-      return this[_duration] <= other[_duration];
+      return dart.notNull(this[_duration]) <= dart.notNull(other[_duration]);
     }
     ['>='](other) {
-      return this[_duration] >= other[_duration];
+      return dart.notNull(this[_duration]) >= dart.notNull(other[_duration]);
     }
     get inDays() {
-      return (this[_duration] / Duration.MICROSECONDS_PER_DAY).truncate();
+      return (dart.notNull(this[_duration]) / dart.notNull(Duration.MICROSECONDS_PER_DAY)).truncate();
     }
     get inHours() {
-      return (this[_duration] / Duration.MICROSECONDS_PER_HOUR).truncate();
+      return (dart.notNull(this[_duration]) / dart.notNull(Duration.MICROSECONDS_PER_HOUR)).truncate();
     }
     get inMinutes() {
-      return (this[_duration] / Duration.MICROSECONDS_PER_MINUTE).truncate();
+      return (dart.notNull(this[_duration]) / dart.notNull(Duration.MICROSECONDS_PER_MINUTE)).truncate();
     }
     get inSeconds() {
-      return (this[_duration] / Duration.MICROSECONDS_PER_SECOND).truncate();
+      return (dart.notNull(this[_duration]) / dart.notNull(Duration.MICROSECONDS_PER_SECOND)).truncate();
     }
     get inMilliseconds() {
-      return (this[_duration] / Duration.MICROSECONDS_PER_MILLISECOND).truncate();
+      return (dart.notNull(this[_duration]) / dart.notNull(Duration.MICROSECONDS_PER_MILLISECOND)).truncate();
     }
     get inMicroseconds() {
       return this[_duration];
     }
     ['=='](other) {
       if (!dart.is(other, Duration))
         return false;
       return this[_duration] === dart.dload(other, '_duration');
     }
     get hashCode() {
       return this[_duration].hashCode;
     }
     compareTo(other) {
       return this[_duration].compareTo(other[_duration]);
     }
     toString() {
       // Function sixDigits: (int) → String
       function sixDigits(n) {
-        if (n >= 100000)
+        if (dart.notNull(n) >= 100000)
           return `${n}`;
-        if (n >= 10000)
+        if (dart.notNull(n) >= 10000)
           return `0${n}`;
-        if (n >= 1000)
+        if (dart.notNull(n) >= 1000)
           return `00${n}`;
-        if (n >= 100)
+        if (dart.notNull(n) >= 100)
           return `000${n}`;
-        if (n >= 10)
+        if (dart.notNull(n) >= 10)
           return `0000${n}`;
         return `00000${n}`;
       }
       // Function twoDigits: (int) → String
       function twoDigits(n) {
-        if (n >= 10)
+        if (dart.notNull(n) >= 10)
           return `${n}`;
         return `0${n}`;
       }
-      if (this.inMicroseconds < 0) {
+      if (dart.notNull(this.inMicroseconds) < 0) {
         return `-${dart.throw_("Unimplemented PrefixExpression: -this")}`;
       }
-      let twoDigitMinutes = twoDigits(dart.notNull(this.inMinutes.remainder(MINUTES_PER_HOUR)));
-      let twoDigitSeconds = twoDigits(dart.notNull(this.inSeconds.remainder(SECONDS_PER_MINUTE)));
-      let sixDigitUs = sixDigits(dart.notNull(this.inMicroseconds.remainder(MICROSECONDS_PER_SECOND)));
+      let twoDigitMinutes = twoDigits(this.inMinutes.remainder(MINUTES_PER_HOUR));
+      let twoDigitSeconds = twoDigits(this.inSeconds.remainder(SECONDS_PER_MINUTE));
+      let sixDigitUs = sixDigits(this.inMicroseconds.remainder(MICROSECONDS_PER_SECOND));
       return `${this.inHours}:${twoDigitMinutes}:${twoDigitSeconds}.${sixDigitUs}`;
     }
     get isNegative() {
-      return this[_duration] < 0;
+      return dart.notNull(this[_duration]) < 0;
     }
     abs() {
       return new Duration._microseconds(this[_duration].abs());
     }
     ['-']() {
-      return new Duration._microseconds(-this[_duration]);
+      return new Duration._microseconds(-dart.notNull(this[_duration]));
     }
   }
   dart.defineNamedConstructor(Duration, '_microseconds');
   Duration.MICROSECONDS_PER_MILLISECOND = 1000;
   Duration.MILLISECONDS_PER_SECOND = 1000;
   Duration.SECONDS_PER_MINUTE = 60;
   Duration.MINUTES_PER_HOUR = 60;
   Duration.HOURS_PER_DAY = 24;
-  Duration.MICROSECONDS_PER_SECOND = MICROSECONDS_PER_MILLISECOND * MILLISECONDS_PER_SECOND;
-  Duration.MICROSECONDS_PER_MINUTE = MICROSECONDS_PER_SECOND * SECONDS_PER_MINUTE;
-  Duration.MICROSECONDS_PER_HOUR = MICROSECONDS_PER_MINUTE * MINUTES_PER_HOUR;
-  Duration.MICROSECONDS_PER_DAY = MICROSECONDS_PER_HOUR * HOURS_PER_DAY;
-  Duration.MILLISECONDS_PER_MINUTE = MILLISECONDS_PER_SECOND * SECONDS_PER_MINUTE;
-  Duration.MILLISECONDS_PER_HOUR = MILLISECONDS_PER_MINUTE * MINUTES_PER_HOUR;
-  Duration.MILLISECONDS_PER_DAY = MILLISECONDS_PER_HOUR * HOURS_PER_DAY;
-  Duration.SECONDS_PER_HOUR = SECONDS_PER_MINUTE * MINUTES_PER_HOUR;
-  Duration.SECONDS_PER_DAY = SECONDS_PER_HOUR * HOURS_PER_DAY;
-  Duration.MINUTES_PER_DAY = MINUTES_PER_HOUR * HOURS_PER_DAY;
+  Duration.MICROSECONDS_PER_SECOND = dart.notNull(MICROSECONDS_PER_MILLISECOND) * dart.notNull(MILLISECONDS_PER_SECOND);
+  Duration.MICROSECONDS_PER_MINUTE = dart.notNull(MICROSECONDS_PER_SECOND) * dart.notNull(SECONDS_PER_MINUTE);
+  Duration.MICROSECONDS_PER_HOUR = dart.notNull(MICROSECONDS_PER_MINUTE) * dart.notNull(MINUTES_PER_HOUR);
+  Duration.MICROSECONDS_PER_DAY = dart.notNull(MICROSECONDS_PER_HOUR) * dart.notNull(HOURS_PER_DAY);
+  Duration.MILLISECONDS_PER_MINUTE = dart.notNull(MILLISECONDS_PER_SECOND) * dart.notNull(SECONDS_PER_MINUTE);
+  Duration.MILLISECONDS_PER_HOUR = dart.notNull(MILLISECONDS_PER_MINUTE) * dart.notNull(MINUTES_PER_HOUR);
+  Duration.MILLISECONDS_PER_DAY = dart.notNull(MILLISECONDS_PER_HOUR) * dart.notNull(HOURS_PER_DAY);
+  Duration.SECONDS_PER_HOUR = dart.notNull(SECONDS_PER_MINUTE) * dart.notNull(MINUTES_PER_HOUR);
+  Duration.SECONDS_PER_DAY = dart.notNull(SECONDS_PER_HOUR) * dart.notNull(HOURS_PER_DAY);
+  Duration.MINUTES_PER_DAY = dart.notNull(MINUTES_PER_HOUR) * dart.notNull(HOURS_PER_DAY);
   Duration.ZERO = new Duration({seconds: 0});
   let _stringToSafeString = Symbol('_stringToSafeString');
   let _objectToString = Symbol('_objectToString');
   class Error extends dart.Object {
     Error() {
     }
     static safeToString(object) {
-      if (dart.notNull(dart.notNull(dart.is(object, num)) || dart.notNull(typeof object == boolean)) || dart.notNull(null === object)) {
+      if (dart.notNull(dart.is(object, num)) || dart.notNull(typeof object == boolean) || dart.notNull(null === object)) {
         return object.toString();
       }
       if (typeof object == string) {
         return _stringToSafeString(object);
       }
       return _objectToString(object);
     }
     static [_stringToSafeString](string) {
       return _js_helper.jsonEncodeNative(string);
     }
@@ skipping 84 matching lines @@
       super.ArgumentError$value(invalidValue, name, message !== null ? message : "Invalid value");
     }
     RangeError$index(index, indexable, name, message, length) {
       return new IndexError(index, indexable, name, message, length);
     }
     static checkValueInInterval(value, minValue, maxValue, name, message) {
       if (name === void 0)
         name = null;
       if (message === void 0)
         message = null;
-      if (dart.notNull(value < minValue) || dart.notNull(value > maxValue)) {
+      if (dart.notNull(value) < dart.notNull(minValue) || dart.notNull(value) > dart.notNull(maxValue)) {
         throw new RangeError.range(value, minValue, maxValue, name, message);
       }
     }
     static checkValidIndex(index, indexable, name, length, message) {
       if (name === void 0)
         name = null;
       if (length === void 0)
         length = null;
       if (message === void 0)
         message = null;
       if (length === null)
         length = dart.as(dart.dload(indexable, 'length'), int);
-      if (dart.notNull(index < 0) || dart.notNull(index >= length)) {
+      if (dart.notNull(index) < 0 || dart.notNull(index) >= dart.notNull(length)) {
         if (name === null)
           name = "index";
         throw new RangeError.index(index, indexable, name, message, length);
       }
     }
     static checkValidRange(start, end, length, startName, endName, message) {
       if (startName === void 0)
         startName = null;
       if (endName === void 0)
         endName = null;
       if (message === void 0)
         message = null;
-      if (dart.notNull(start < 0) || dart.notNull(start > length)) {
+      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(length)) {
         if (startName === null)
           startName = "start";
         throw new RangeError.range(start, 0, length, startName, message);
       }
-      if (dart.notNull(end !== null) && dart.notNull(dart.notNull(end < start) || dart.notNull(end > length))) {
+      if (end !== null && (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(length))) {
         if (endName === null)
           endName = "end";
         throw new RangeError.range(end, start, length, endName, message);
       }
     }
     static checkNotNegative(value, name, message) {
       if (name === void 0)
         name = null;
       if (message === void 0)
         message = null;
-      if (value < 0)
-        throw new RangeError.range(value, 0, dart.as(null, int), name, message);
+      if (dart.notNull(value) < 0)
+        throw new RangeError.range(value, 0, null, name, message);
     }
     toString() {
       if (!dart.notNull(this[_hasValue]))
         return `RangeError: ${this.message}`;
       let value = Error.safeToString(this.invalidValue);
       let explanation = "";
       if (this.start === null) {
         if (this.end !== null) {
           explanation = `: Not less than or equal to ${this.end}`;
         }
@@ skipping 21 matching lines @@
       if (length === void 0)
         length = null;
       this.indexable = indexable;
       this.length = dart.as(length !== null ? length : dart.dload(indexable, 'length'), int);
       super.ArgumentError$value(invalidValue, name, message !== null ? message : "Index out of range");
     }
     get start() {
       return 0;
     }
     get end() {
-      return this.length - 1;
+      return dart.notNull(this.length) - 1;
     }
     toString() {
       dart.assert(this[_hasValue]);
       let target = Error.safeToString(this.indexable);
       let explanation = `index should be less than ${this.length}`;
       if (dart.dbinary(this.invalidValue, '<', 0)) {
         explanation = "index must not be negative";
       }
       return `RangeError: ${this.message} (${target}[${this.invalidValue}]): ${explanation}`;
     }
@@ skipping 26 matching lines @@
       this[_memberName] = memberName;
       this[_arguments] = positionalArguments;
       this[_namedArguments] = namedArguments;
       this[_existingArgumentNames] = existingArgumentNames;
       super.Error();
     }
     toString() {
       let sb = new StringBuffer();
       let i = 0;
       if (this[_arguments] !== null) {
-        for (; i < this[_arguments].length; i++) {
-          if (i > 0) {
+        for (; dart.notNull(i) < dart.notNull(this[_arguments].length); dart.notNull(i)++) {
+          if (dart.notNull(i) > 0) {
             sb.write(", ");
           }
           sb.write(Error.safeToString(this[_arguments].get(i)));
         }
       }
       if (this[_namedArguments] !== null) {
         this[_namedArguments].forEach(((key, value) => {
-          if (i > 0) {
+          if (dart.notNull(i) > 0) {
             sb.write(", ");
           }
           sb.write(_symbolToString(key));
           sb.write(": ");
           sb.write(Error.safeToString(value));
-          i++;
+          dart.notNull(i)++;
         }).bind(this));
       }
       if (this[_existingArgumentNames] === null) {
         return `NoSuchMethodError : method not found: '${this[_memberName]}'\n` + `Receiver: ${Error.safeToString(this[_receiver])}\n` + `Arguments: [${sb}]`;
       } else {
         let actualParameters = sb.toString();
         sb = new StringBuffer();
-        for (let i = 0; i < this[_existingArgumentNames].length; i++) {
-          if (i > 0) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(this[_existingArgumentNames].length); dart.notNull(i)++) {
+          if (dart.notNull(i) > 0) {
             sb.write(", ");
           }
           sb.write(this[_existingArgumentNames].get(i));
         }
         let formalParameters = sb.toString();
         return "NoSuchMethodError: incorrect number of arguments passed to " + `method named '${this[_memberName]}'\n` + `Receiver: ${Error.safeToString(this[_receiver])}\n` + `Tried calling: ${this[_memberName]}(${actualParameters})\n` + `Found: ${this[_memberName]}(${formalParameters})`;
       }
     }
   }
   class UnsupportedError extends Error {
@@ skipping 106 matching lines @@
       if (dart.notNull(this.message !== null) && dart.notNull(!dart.equals("", this.message))) {
         report = `${report}: ${this.message}`;
       }
       let offset = this.offset;
       if (!(typeof this.source == string)) {
         if (offset !== -1) {
           report = ` (at offset ${offset})`;
         }
         return report;
       }
-      if (dart.notNull(offset !== -1) && dart.notNull(dart.notNull(offset < 0) || dart.notNull(offset['>'](dart.dload(this.source, 'length'))))) {
+      if (offset !== -1 && (dart.notNull(offset) < 0 || offset['>'](dart.dload(this.source, 'length')))) {
         offset = -1;
       }
       if (offset === -1) {
         let source = dart.as(this.source, String);
-        if (source.length > 78) {
+        if (dart.notNull(source.length) > 78) {
           source = String['+'](source.substring(0, 75), "...");
         }
         return `${report}\n${source}`;
       }
       let lineNum = 1;
       let lineStart = 0;
       let lastWasCR = null;
-      for (let i = 0; i < offset; i++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(offset); dart.notNull(i)++) {
         let char = dart.as(dart.dinvoke(this.source, 'codeUnitAt', i), int);
         if (char === 10) {
-          if (dart.notNull(lineStart !== i) || dart.notNull(!dart.notNull(lastWasCR))) {
-            lineNum++;
+          if (lineStart !== i || !dart.notNull(lastWasCR)) {
+            dart.notNull(lineNum)++;
           }
-          lineStart = i + 1;
+          lineStart = dart.notNull(i) + 1;
           lastWasCR = false;
         } else if (char === 13) {
-          lineNum++;
-          lineStart = i + 1;
+          dart.notNull(lineNum)++;
+          lineStart = dart.notNull(i) + 1;
           lastWasCR = true;
         }
       }
-      if (lineNum > 1) {
-        report = ` (at line ${lineNum}, character ${offset - lineStart + 1})\n`;
+      if (dart.notNull(lineNum) > 1) {
+        report = ` (at line ${lineNum}, character ${dart.notNull(offset) - dart.notNull(lineStart) + 1})\n`;
       } else {
-        report = ` (at character ${offset + 1})\n`;
+        report = ` (at character ${dart.notNull(offset) + 1})\n`;
       }
       let lineEnd = dart.as(dart.dload(this.source, 'length'), int);
-      for (let i = offset; i['<'](dart.dload(this.source, 'length')); i++) {
+      for (let i = offset; i['<'](dart.dload(this.source, 'length')); dart.notNull(i)++) {
         let char = dart.as(dart.dinvoke(this.source, 'codeUnitAt', i), int);
-        if (dart.notNull(char === 10) || dart.notNull(char === 13)) {
+        if (char === 10 || char === 13) {
           lineEnd = i;
           break;
         }
       }
-      let length = lineEnd - lineStart;
+      let length = dart.notNull(lineEnd) - dart.notNull(lineStart);
       let start = lineStart;
       let end = lineEnd;
       let prefix = "";
       let postfix = "";
-      if (length > 78) {
-        let index = offset - lineStart;
-        if (index < 75) {
-          end = start + 75;
+      if (dart.notNull(length) > 78) {
+        let index = dart.notNull(offset) - dart.notNull(lineStart);
+        if (dart.notNull(index) < 75) {
+          end = dart.notNull(start) + 75;
           postfix = "...";
-        } else if (end - offset < 75) {
-          start = end - 75;
+        } else if (dart.notNull(end) - dart.notNull(offset) < 75) {
+          start = dart.notNull(end) - 75;
           prefix = "...";
         } else {
-          start = offset - 36;
-          end = offset + 36;
+          start = dart.notNull(offset) - 36;
+          end = dart.notNull(offset) + 36;
           prefix = postfix = "...";
         }
       }
       let slice = dart.as(dart.dinvoke(this.source, 'substring', start, end), String);
-      let markOffset = offset - start + prefix.length;
+      let markOffset = dart.notNull(offset) - dart.notNull(start) + dart.notNull(prefix.length);
       return `${report}${prefix}${slice}${postfix}\n${String['*'](" ", markOffset)}^\n`;
     }
   }
   class IntegerDivisionByZeroException extends dart.Object {
     IntegerDivisionByZeroException() {
     }
     toString() {
       return "IntegerDivisionByZeroException";
     }
   }
@@ skipping 16 matching lines @@
         let values = _js_helper.Primitives.getProperty(object, _EXPANDO_PROPERTY_NAME);
         if (values === null) {
           values = new Object();
           _js_helper.Primitives.setProperty(object, _EXPANDO_PROPERTY_NAME, values);
         }
         _js_helper.Primitives.setProperty(values, this[_getKey](), value);
       }
       [_getKey]() {
         let key = dart.as(_js_helper.Primitives.getProperty(this, _KEY_PROPERTY_NAME), String);
         if (key === null) {
-          key = `expando$key$${_keyCount++}`;
+          key = `expando$key$${dart.notNull(_keyCount)++}`;
           _js_helper.Primitives.setProperty(this, _KEY_PROPERTY_NAME, key);
         }
         return key;
       }
     }
     Expando._KEY_PROPERTY_NAME = 'expando$key';
     Expando._EXPANDO_PROPERTY_NAME = 'expando$values';
     Expando._keyCount = 0;
     return Expando;
   });
@@ skipping 38 matching lines @@
       return dart.notNull(this.isGetter) || dart.notNull(this.isSetter);
     }
   }
   let Iterable$ = dart.generic(function(E) {
     class Iterable extends dart.Object {
       Iterable() {
       }
       Iterable$generate(count, generator) {
         if (generator === void 0)
           generator = null;
-        if (count <= 0)
+        if (dart.notNull(count) <= 0)
           return new _internal.EmptyIterable();
         return new _GeneratorIterable(count, generator);
       }
       join(separator) {
         if (separator === void 0)
           separator = "";
         let buffer = new StringBuffer();
         buffer.writeAll(this, separator);
         return buffer.toString();
       }
@@ skipping 26 matching lines @@
       _GeneratorIterable$slice($_start, $_end, $_generator) {
         this[_start] = $_start;
         this[_end] = $_end;
         this[_generator] = $_generator;
         super.IterableBase();
       }
       get iterator() {
         return new _GeneratorIterator(this[_start], this[_end], this[_generator]);
       }
       get length() {
-        return this[_end] - this[_start];
+        return dart.notNull(this[_end]) - dart.notNull(this[_start]);
       }
       skip(count) {
         RangeError.checkNotNegative(count, "count");
         if (count === 0)
           return this;
-        let newStart = this[_start] + count;
-        if (newStart >= this[_end])
+        let newStart = dart.notNull(this[_start]) + dart.notNull(count);
+        if (dart.notNull(newStart) >= dart.notNull(this[_end]))
           return new _internal.EmptyIterable();
         return new _GeneratorIterable.slice(newStart, this[_end], this[_generator]);
       }
       take(count) {
         RangeError.checkNotNegative(count, "count");
         if (count === 0)
           return new _internal.EmptyIterable();
-        let newEnd = this[_start] + count;
-        if (newEnd >= this[_end])
+        let newEnd = dart.notNull(this[_start]) + dart.notNull(count);
+        if (dart.notNull(newEnd) >= dart.notNull(this[_end]))
           return this;
         return new _GeneratorIterable.slice(this[_start], newEnd, this[_generator]);
       }
       static [_id](n) {
         return n;
       }
     }
     dart.defineNamedConstructor(_GeneratorIterable, 'slice');
     return _GeneratorIterable;
   });
   let _GeneratorIterable = _GeneratorIterable$(dynamic);
   let _index = Symbol('_index');
   let _current = Symbol('_current');
   let _GeneratorIterator$ = dart.generic(function(E) {
     class _GeneratorIterator extends dart.Object {
       _GeneratorIterator($_index, $_end, $_generator) {
         this[_index] = $_index;
         this[_end] = $_end;
         this[_generator] = $_generator;
-        this[_current] = dart.as(null, E);
+        this[_current] = null;
       }
       moveNext() {
-        if (this[_index] < this[_end]) {
+        if (dart.notNull(this[_index]) < dart.notNull(this[_end])) {
           this[_current] = this[_generator](this[_index]);
-          this[_index]++;
+          dart.notNull(this[_index])++;
           return true;
         } else {
-          this[_current] = dart.as(null, E);
+          this[_current] = null;
           return false;
         }
       }
       get current() {
         return this[_current];
       }
     }
     return _GeneratorIterator;
   });
   let _GeneratorIterator = _GeneratorIterator$(dynamic);
@@ skipping 14 matching lines @@
       List(length) {
         if (length === void 0)
           length = new _ListConstructorSentinel();
         if (length === new _ListConstructorSentinel()) {
           return new _interceptors.JSArray.emptyGrowable();
         }
         return new _interceptors.JSArray.fixed(length);
       }
       List$filled(length, fill) {
         let result = new _interceptors.JSArray.fixed(length);
-        if (dart.notNull(length !== 0) && dart.notNull(fill !== null)) {
-          for (let i = 0; i < result.length; i++) {
+        if (length !== 0 && dart.notNull(fill !== null)) {
+          for (let i = 0; dart.notNull(i) < dart.notNull(result.length); dart.notNull(i)++) {
             result.set(i, fill);
           }
         }
         return dart.as(result, List$(E));
       }
       List$from(elements, opt$) {
         let growable = opt$.growable === void 0 ? true : opt$.growable;
         let list = new List();
         for (let e of elements) {
           list.add(e);
         }
         if (growable)
           return list;
         return dart.as(_internal.makeListFixedLength(list), List$(E));
       }
       List$generate(length, generator, opt$) {
         let growable = opt$.growable === void 0 ? true : opt$.growable;
         let result = null;
         if (growable) {
           result = ((_) => {
             _.length = length;
             return _;
           }).bind(this)(new List.from([]));
         } else {
           result = new List(length);
         }
-        for (let i = 0; i < length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(length); dart.notNull(i)++) {
           result.set(i, generator(i));
         }
         return result;
       }
     }
     dart.defineNamedConstructor(List, 'filled');
     dart.defineNamedConstructor(List, 'from');
     dart.defineNamedConstructor(List, 'generate');
     return List;
   });
@@ skipping 136 matching lines @@
       this[_start] = null;
       this[_stop] = null;
       _initTicker();
     }
     start() {
       if (this.isRunning)
         return;
       if (this[_start] === null) {
         this[_start] = _now();
       } else {
-        this[_start] = _now() - dart.notNull(dart.notNull(this[_stop]) - dart.notNull(this[_start]));
+        this[_start] = dart.notNull(_now()) - (dart.notNull(this[_stop]) - dart.notNull(this[_start]));
         this[_stop] = null;
       }
     }
     stop() {
       if (!dart.notNull(this.isRunning))
         return;
       this[_stop] = _now();
     }
     reset() {
       if (this[_start] === null)
         return;
       this[_start] = _now();
       if (this[_stop] !== null) {
         this[_stop] = this[_start];
       }
     }
     get elapsedTicks() {
       if (this[_start] === null) {
         return 0;
       }
-      return dart.notNull(this[_stop] === null ? _now() - dart.notNull(this[_start]) : dart.notNull(this[_stop]) - dart.notNull(this[_start]));
+      return this[_stop] === null ? dart.notNull(_now()) - dart.notNull(this[_start]) : dart.notNull(this[_stop]) - dart.notNull(this[_start]);
     }
     get elapsed() {
       return new Duration({microseconds: this.elapsedMicroseconds});
     }
     get elapsedMicroseconds() {
-      return (this.elapsedTicks * 1000000 / this.frequency).truncate();
+      return (dart.notNull(this.elapsedTicks) * 1000000 / dart.notNull(this.frequency)).truncate();
     }
     get elapsedMilliseconds() {
-      return (this.elapsedTicks * 1000 / this.frequency).truncate();
+      return (dart.notNull(this.elapsedTicks) * 1000 / dart.notNull(this.frequency)).truncate();
     }
     get isRunning() {
-      return dart.notNull(this[_start] !== null) && dart.notNull(this[_stop] === null);
+      return this[_start] !== null && this[_stop] === null;
     }
     static [_initTicker]() {
       _js_helper.Primitives.initTicker();
       _frequency = _js_helper.Primitives.timerFrequency;
     }
     static [_now]() {
       return dart.as(dart.dinvoke(_js_helper.Primitives, 'timerTicks'), int);
     }
   }
   Stopwatch._frequency = null;
   let _stringFromIterable = Symbol('_stringFromIterable');
   class String extends dart.Object {
     String$fromCharCodes(charCodes, start, end) {
       if (start === void 0)
         start = 0;
       if (end === void 0)
         end = null;
       if (!dart.is(charCodes, _interceptors.JSArray)) {
         return _stringFromIterable(charCodes, start, end);
       }
       let list = dart.as(charCodes, List);
       let len = list.length;
-      if (dart.notNull(start < 0) || dart.notNull(start > len)) {
+      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(len)) {
         throw new RangeError.range(start, 0, len);
       }
       if (end === null) {
         end = len;
-      } else if (dart.notNull(end < start) || dart.notNull(end > len)) {
+      } else if (dart.notNull(end) < dart.notNull(start) || dart.notNull(end) > dart.notNull(len)) {
         throw new RangeError.range(end, start, len);
       }
-      if (dart.notNull(start > 0) || dart.notNull(end < len)) {
+      if (dart.notNull(start) > 0 || dart.notNull(end) < dart.notNull(len)) {
         list = list.sublist(start, end);
       }
       return _js_helper.Primitives.stringFromCharCodes(list);
     }
     String$fromCharCode(charCode) {
       return _js_helper.Primitives.stringFromCharCode(charCode);
     }
     String$fromEnvironment(name, opt$) {
       let defaultValue = opt$.defaultValue === void 0 ? null : opt$.defaultValue;
       throw new UnsupportedError('String.fromEnvironment can only be used as a const constructor');
     }
     static [_stringFromIterable](charCodes, start, end) {
-      if (start < 0)
+      if (dart.notNull(start) < 0)
         throw new RangeError.range(start, 0, charCodes.length);
-      if (dart.notNull(end !== null) && dart.notNull(end < start)) {
+      if (end !== null && dart.notNull(end) < dart.notNull(start)) {
         throw new RangeError.range(end, start, charCodes.length);
       }
       let it = charCodes.iterator;
-      for (let i = 0; i < start; i++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(start); dart.notNull(i)++) {
         if (!dart.notNull(it.moveNext())) {
           throw new RangeError.range(start, 0, i);
         }
       }
       let list = new List.from([]);
       if (end === null) {
         while (it.moveNext())
           list.add(it.current);
       } else {
-        for (let i = start; i < end; i++) {
+        for (let i = start; dart.notNull(i) < dart.notNull(end); dart.notNull(i)++) {
           if (!dart.notNull(it.moveNext())) {
             throw new RangeError.range(end, start, i);
           }
           list.add(it.current);
         }
       }
       return _js_helper.Primitives.stringFromCharCodes(list);
     }
   }
   dart.defineNamedConstructor(String, 'fromCharCodes');
   dart.defineNamedConstructor(String, 'fromCharCode');
   dart.defineNamedConstructor(String, 'fromEnvironment');
   class Runes extends collection.IterableBase$(int) {
     Runes(string) {
       this.string = string;
       super.IterableBase();
     }
     get iterator() {
       return new RuneIterator(this.string);
     }
     get last() {
       if (this.string.length === 0) {
         throw new StateError('No elements.');
       }
       let length = this.string.length;
-      let code = this.string.codeUnitAt(length - 1);
-      if (dart.notNull(_isTrailSurrogate(code)) && dart.notNull(this.string.length > 1)) {
-        let previousCode = this.string.codeUnitAt(length - 2);
+      let code = this.string.codeUnitAt(dart.notNull(length) - 1);
+      if (dart.notNull(_isTrailSurrogate(code)) && dart.notNull(this.string.length) > 1) {
+        let previousCode = this.string.codeUnitAt(dart.notNull(length) - 2);
         if (_isLeadSurrogate(previousCode)) {
           return _combineSurrogatePair(previousCode, code);
         }
       }
       return code;
     }
   }
   // Function _isLeadSurrogate: (int) → bool
   function _isLeadSurrogate(code) {
-    return (code & 64512) === 55296;
+    return (dart.notNull(code) & 64512) === 55296;
   }
   // Function _isTrailSurrogate: (int) → bool
   function _isTrailSurrogate(code) {
-    return (code & 64512) === 56320;
+    return (dart.notNull(code) & 64512) === 56320;
   }
   // Function _combineSurrogatePair: (int, int) → int
   function _combineSurrogatePair(start, end) {
-    return 65536 + ((start & 1023) << 10) + (end & 1023);
+    return 65536 + ((dart.notNull(start) & 1023) << 10) + (dart.notNull(end) & 1023);
   }
   let _position = Symbol('_position');
   let _nextPosition = Symbol('_nextPosition');
   let _currentCodePoint = Symbol('_currentCodePoint');
   let _checkSplitSurrogate = Symbol('_checkSplitSurrogate');
   class RuneIterator extends dart.Object {
     RuneIterator(string) {
       this.string = string;
       this[_position] = 0;
       this[_nextPosition] = 0;
       this[_currentCodePoint] = null;
     }
     RuneIterator$at(string, index) {
       this.string = string;
       this[_position] = index;
       this[_nextPosition] = index;
       this[_currentCodePoint] = null;
       RangeError.checkValueInInterval(index, 0, string.length);
       this[_checkSplitSurrogate](index);
     }
     [_checkSplitSurrogate](index) {
-      if (dart.notNull(dart.notNull(dart.notNull(index > 0) && dart.notNull(index < this.string.length)) && dart.notNull(_isLeadSurrogate(this.string.codeUnitAt(index - 1)))) && dart.notNull(_isTrailSurrogate(this.string.codeUnitAt(index)))) {
+      if (dart.notNull(index) > 0 && dart.notNull(index) < dart.notNull(this.string.length) && dart.notNull(_isLeadSurrogate(this.string.codeUnitAt(dart.notNull(index) - 1))) && dart.notNull(_isTrailSurrogate(this.string.codeUnitAt(index)))) {
         throw new ArgumentError(`Index inside surrogate pair: ${index}`);
       }
     }
     get rawIndex() {
       return dart.as(this[_position] !== this[_nextPosition] ? this[_position] : null, int);
     }
     set rawIndex(rawIndex) {
       RangeError.checkValidIndex(rawIndex, this.string, "rawIndex");
       this.reset(rawIndex);
       this.moveNext();
     }
     reset(rawIndex) {
       if (rawIndex === void 0)
         rawIndex = 0;
       RangeError.checkValueInInterval(rawIndex, 0, this.string.length, "rawIndex");
       this[_checkSplitSurrogate](rawIndex);
       this[_position] = this[_nextPosition] = rawIndex;
       this[_currentCodePoint] = null;
     }
     get current() {
-      return dart.notNull(this[_currentCodePoint]);
+      return this[_currentCodePoint];
     }
     get currentSize() {
-      return this[_nextPosition] - this[_position];
+      return dart.notNull(this[_nextPosition]) - dart.notNull(this[_position]);
     }
     get currentAsString() {
       if (this[_position] === this[_nextPosition])
         return null;
-      if (this[_position] + 1 === this[_nextPosition])
+      if (dart.notNull(this[_position]) + 1 === this[_nextPosition])
         return this.string.get(this[_position]);
       return this.string.substring(this[_position], this[_nextPosition]);
     }
     moveNext() {
       this[_position] = this[_nextPosition];
       if (this[_position] === this.string.length) {
         this[_currentCodePoint] = null;
         return false;
       }
       let codeUnit = this.string.codeUnitAt(this[_position]);
-      let nextPosition = this[_position] + 1;
-      if (dart.notNull(_isLeadSurrogate(codeUnit)) && dart.notNull(nextPosition < this.string.length)) {
+      let nextPosition = dart.notNull(this[_position]) + 1;
+      if (dart.notNull(_isLeadSurrogate(codeUnit)) && dart.notNull(nextPosition) < dart.notNull(this.string.length)) {
         let nextCodeUnit = this.string.codeUnitAt(nextPosition);
         if (_isTrailSurrogate(nextCodeUnit)) {
-          this[_nextPosition] = nextPosition + 1;
+          this[_nextPosition] = dart.notNull(nextPosition) + 1;
           this[_currentCodePoint] = _combineSurrogatePair(codeUnit, nextCodeUnit);
           return true;
         }
       }
       this[_nextPosition] = nextPosition;
       this[_currentCodePoint] = codeUnit;
       return true;
     }
     movePrevious() {
       this[_nextPosition] = this[_position];
       if (this[_position] === 0) {
         this[_currentCodePoint] = null;
         return false;
       }
-      let position = this[_position] - 1;
+      let position = dart.notNull(this[_position]) - 1;
       let codeUnit = this.string.codeUnitAt(position);
-      if (dart.notNull(_isTrailSurrogate(codeUnit)) && dart.notNull(position > 0)) {
-        let prevCodeUnit = this.string.codeUnitAt(position - 1);
+      if (dart.notNull(_isTrailSurrogate(codeUnit)) && dart.notNull(position) > 0) {
+        let prevCodeUnit = this.string.codeUnitAt(dart.notNull(position) - 1);
         if (_isLeadSurrogate(prevCodeUnit)) {
-          this[_position] = position - 1;
+          this[_position] = dart.notNull(position) - 1;
           this[_currentCodePoint] = _combineSurrogatePair(prevCodeUnit, codeUnit);
           return true;
         }
       }
       this[_position] = position;
       this[_currentCodePoint] = codeUnit;
       return true;
     }
   }
   dart.defineNamedConstructor(RuneIterator, 'at');
@@ skipping 118 matching lines @@
       this[_writeAuthority](sb);
       return sb.toString();
     }
     get userInfo() {
       return this[_userInfo];
     }
     get host() {
       if (this[_host] === null)
         return "";
       if (this[_host].startsWith('[')) {
-        return this[_host].substring(1, this[_host].length - 1);
+        return this[_host].substring(1, dart.notNull(this[_host].length) - 1);
       }
       return this[_host];
     }
     get port() {
       if (this[_port] === null)
         return _defaultPort(this.scheme);
-      return dart.notNull(this[_port]);
+      return this[_port];
     }
     static [_defaultPort](scheme) {
       if (dart.equals(scheme, "http"))
         return 80;
       if (dart.equals(scheme, "https"))
         return 443;
       return 0;
     }
     get path() {
       return this[_path];
     }
     get query() {
       return this[_query] === null ? "" : this[_query];
     }
     get fragment() {
       return this[_fragment] === null ? "" : this[_fragment];
     }
     static parse(uri) {
       // Function isRegName: (int) → bool
       function isRegName(ch) {
-        return dart.notNull(ch < 128) && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_regNameTable, ch >> 4), '&', 1 << (ch & 15)), 0));
+        return dart.notNull(ch) < 128 && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_regNameTable, dart.notNull(ch) >> 4), '&', 1 << (dart.notNull(ch) & 15)), 0));
       }
       let EOI = -1;
       let scheme = "";
       let userinfo = "";
       let host = null;
       let port = null;
       let path = null;
       let query = null;
       let fragment = null;
       let index = 0;
       let pathStart = 0;
       let char = EOI;
       // Function parseAuth: () → void
       function parseAuth() {
         if (index === uri.length) {
           char = EOI;
           return;
         }
         let authStart = index;
         let lastColon = -1;
         let lastAt = -1;
         char = uri.codeUnitAt(index);
-        while (index < uri.length) {
+        while (dart.notNull(index) < dart.notNull(uri.length)) {
           char = uri.codeUnitAt(index);
-          if (dart.notNull(dart.notNull(char === _SLASH) || dart.notNull(char === _QUESTION)) || dart.notNull(char === _NUMBER_SIGN)) {
+          if (char === _SLASH || char === _QUESTION || char === _NUMBER_SIGN) {
             break;
           }
           if (char === _AT_SIGN) {
             lastAt = index;
             lastColon = -1;
           } else if (char === _COLON) {
             lastColon = index;
           } else if (char === _LEFT_BRACKET) {
             lastColon = -1;
-            let endBracket = uri.indexOf(']', index + 1);
+            let endBracket = uri.indexOf(']', dart.notNull(index) + 1);
             if (endBracket === -1) {
               index = uri.length;
               char = EOI;
               break;
             } else {
               index = endBracket;
             }
           }
-          index++;
+          dart.notNull(index)++;
           char = EOI;
         }
         let hostStart = authStart;
         let hostEnd = index;
-        if (lastAt >= 0) {
+        if (dart.notNull(lastAt) >= 0) {
           userinfo = _makeUserInfo(uri, authStart, lastAt);
-          hostStart = lastAt + 1;
+          hostStart = dart.notNull(lastAt) + 1;
         }
-        if (lastColon >= 0) {
+        if (dart.notNull(lastColon) >= 0) {
           let portNumber = null;
-          if (lastColon + 1 < index) {
+          if (dart.notNull(lastColon) + 1 < dart.notNull(index)) {
             portNumber = 0;
-            for (let i = lastColon + 1; i < index; i++) {
+            for (let i = dart.notNull(lastColon) + 1; dart.notNull(i) < dart.notNull(index); dart.notNull(i)++) {
               let digit = uri.codeUnitAt(i);
-              if (dart.notNull(_ZERO > digit) || dart.notNull(_NINE < digit)) {
+              if (dart.notNull(_ZERO) > dart.notNull(digit) || dart.notNull(_NINE) < dart.notNull(digit)) {
                 _fail(uri, i, "Invalid port number");
               }
-              portNumber = portNumber * 10 + (digit - _ZERO);
+              portNumber = dart.notNull(portNumber) * 10 + (dart.notNull(digit) - dart.notNull(_ZERO));
             }
           }
           port = _makePort(portNumber, scheme);
           hostEnd = lastColon;
         }
         host = _makeHost(uri, hostStart, hostEnd, true);
-        if (index < uri.length) {
+        if (dart.notNull(index) < dart.notNull(uri.length)) {
           char = uri.codeUnitAt(index);
         }
       }
       let NOT_IN_PATH = 0;
       let IN_PATH = 1;
       let ALLOW_AUTH = 2;
       let state = NOT_IN_PATH;
       let i = index;
-      while (i < uri.length) {
+      while (dart.notNull(i) < dart.notNull(uri.length)) {
         char = uri.codeUnitAt(i);
-        if (dart.notNull(char === _QUESTION) || dart.notNull(char === _NUMBER_SIGN)) {
+        if (char === _QUESTION || char === _NUMBER_SIGN) {
           state = NOT_IN_PATH;
           break;
         }
         if (char === _SLASH) {
           state = i === 0 ? ALLOW_AUTH : IN_PATH;
           break;
         }
         if (char === _COLON) {
           if (i === 0)
             _fail(uri, 0, "Invalid empty scheme");
           scheme = _makeScheme(uri, i);
-          i++;
+          dart.notNull(i)++;
           pathStart = i;
           if (i === uri.length) {
             char = EOI;
             state = NOT_IN_PATH;
           } else {
             char = uri.codeUnitAt(i);
-            if (dart.notNull(char === _QUESTION) || dart.notNull(char === _NUMBER_SIGN)) {
+            if (char === _QUESTION || char === _NUMBER_SIGN) {
               state = NOT_IN_PATH;
             } else if (char === _SLASH) {
               state = ALLOW_AUTH;
             } else {
               state = IN_PATH;
             }
           }
           break;
         }
-        i++;
+        dart.notNull(i)++;
         char = EOI;
       }
       index = i;
       if (state === ALLOW_AUTH) {
         dart.assert(char === _SLASH);
-        index++;
+        dart.notNull(index)++;
         if (index === uri.length) {
           char = EOI;
           state = NOT_IN_PATH;
         } else {
           char = uri.codeUnitAt(index);
           if (char === _SLASH) {
-            index++;
+            dart.notNull(index)++;
             parseAuth();
             pathStart = index;
           }
-          if (dart.notNull(dart.notNull(char === _QUESTION) || dart.notNull(char === _NUMBER_SIGN)) || dart.notNull(char === EOI)) {
+          if (char === _QUESTION || char === _NUMBER_SIGN || char === EOI) {
             state = NOT_IN_PATH;
           } else {
             state = IN_PATH;
           }
         }
       }
-      dart.assert(dart.notNull(state === IN_PATH) || dart.notNull(state === NOT_IN_PATH));
+      dart.assert(state === IN_PATH || state === NOT_IN_PATH);
       if (state === IN_PATH) {
-        while (++index < uri.length) {
+        while (++dart.notNull(index) < dart.notNull(uri.length)) {
           char = uri.codeUnitAt(index);
-          if (dart.notNull(char === _QUESTION) || dart.notNull(char === _NUMBER_SIGN)) {
+          if (char === _QUESTION || char === _NUMBER_SIGN) {
             break;
           }
           char = EOI;
         }
         state = NOT_IN_PATH;
       }
       dart.assert(state === NOT_IN_PATH);
       let isFile = dart.equals(scheme, "file");
       let ensureLeadingSlash = host !== null;
       path = _makePath(uri, pathStart, index, null, ensureLeadingSlash, isFile);
       if (char === _QUESTION) {
-        let numberSignIndex = uri.indexOf('#', index + 1);
-        if (numberSignIndex < 0) {
-          query = _makeQuery(uri, index + 1, uri.length, null);
+        let numberSignIndex = uri.indexOf('#', dart.notNull(index) + 1);
+        if (dart.notNull(numberSignIndex) < 0) {
+          query = _makeQuery(uri, dart.notNull(index) + 1, uri.length, null);
         } else {
-          query = _makeQuery(uri, index + 1, numberSignIndex, null);
-          fragment = _makeFragment(uri, numberSignIndex + 1, uri.length);
+          query = _makeQuery(uri, dart.notNull(index) + 1, numberSignIndex, null);
+          fragment = _makeFragment(uri, dart.notNull(numberSignIndex) + 1, uri.length);
         }
       } else if (char === _NUMBER_SIGN) {
-        fragment = _makeFragment(uri, index + 1, uri.length);
+        fragment = _makeFragment(uri, dart.notNull(index) + 1, uri.length);
       }
       return new Uri._internal(scheme, userinfo, host, port, path, query, fragment);
     }
     static [_fail](uri, index, message) {
       throw new FormatException(message, uri, index);
     }
     Uri$_internal(scheme, $_userInfo, $_host, $_port, $_path, $_query, $_fragment) {
       this.scheme = scheme;
       this[_userInfo] = $_userInfo;
       this[_host] = $_host;
@@ skipping 16 matching lines @@
       let fragment = opt$.fragment === void 0 ? null : opt$.fragment;
       scheme = _makeScheme(scheme, _stringOrNullLength(scheme));
       userInfo = _makeUserInfo(userInfo, 0, _stringOrNullLength(userInfo));
       host = _makeHost(host, 0, _stringOrNullLength(host), false);
       if (dart.equals(query, ""))
         query = null;
       query = _makeQuery(query, 0, _stringOrNullLength(query), queryParameters);
       fragment = _makeFragment(fragment, 0, _stringOrNullLength(fragment));
       port = _makePort(port, scheme);
       let isFile = dart.equals(scheme, "file");
-      if (dart.notNull(host === null) && dart.notNull(dart.notNull(dart.notNull(userInfo.isNotEmpty) || dart.notNull(port !== null)) || dart.notNull(isFile))) {
+      if (dart.notNull(host === null) && (dart.notNull(userInfo.isNotEmpty) || port !== null || dart.notNull(isFile))) {
         host = "";
       }
       let ensureLeadingSlash = host !== null;
       path = _makePath(path, 0, _stringOrNullLength(path), pathSegments, ensureLeadingSlash, isFile);
       return new Uri._internal(scheme, userInfo, host, port, path, query, fragment);
     }
     Uri$http(authority, unencodedPath, queryParameters) {
       if (queryParameters === void 0)
         queryParameters = null;
       return _makeHttpUri("http", authority, unencodedPath, queryParameters);
     }
     Uri$https(authority, unencodedPath, queryParameters) {
       if (queryParameters === void 0)
         queryParameters = null;
       return _makeHttpUri("https", authority, unencodedPath, queryParameters);
     }
     static [_makeHttpUri](scheme, authority, unencodedPath, queryParameters) {
       let userInfo = "";
       let host = null;
       let port = null;
       if (dart.notNull(authority !== null) && dart.notNull(authority.isNotEmpty)) {
         let hostStart = 0;
         let hasUserInfo = false;
-        for (let i = 0; i < authority.length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(authority.length); dart.notNull(i)++) {
           if (authority.codeUnitAt(i) === _AT_SIGN) {
             hasUserInfo = true;
             userInfo = authority.substring(0, i);
-            hostStart = i + 1;
+            hostStart = dart.notNull(i) + 1;
             break;
           }
         }
         let hostEnd = hostStart;
-        if (dart.notNull(hostStart < authority.length) && dart.notNull(authority.codeUnitAt(hostStart) === _LEFT_BRACKET)) {
-          for (; hostEnd < authority.length; hostEnd++) {
+        if (dart.notNull(hostStart) < dart.notNull(authority.length) && authority.codeUnitAt(hostStart) === _LEFT_BRACKET) {
+          for (; dart.notNull(hostEnd) < dart.notNull(authority.length); dart.notNull(hostEnd)++) {
             if (authority.codeUnitAt(hostEnd) === _RIGHT_BRACKET)
               break;
           }
           if (hostEnd === authority.length) {
             throw new FormatException("Invalid IPv6 host entry.", authority, hostStart);
           }
-          parseIPv6Address(authority, hostStart + 1, hostEnd);
-          hostEnd++;
-          if (dart.notNull(hostEnd !== authority.length) && dart.notNull(authority.codeUnitAt(hostEnd) !== _COLON)) {
+          parseIPv6Address(authority, dart.notNull(hostStart) + 1, hostEnd);
+          dart.notNull(hostEnd)++;
+          if (hostEnd !== authority.length && authority.codeUnitAt(hostEnd) !== _COLON) {
             throw new FormatException("Invalid end of authority", authority, hostEnd);
           }
         }
         let hasPort = false;
-        for (; hostEnd < authority.length; hostEnd++) {
+        for (; dart.notNull(hostEnd) < dart.notNull(authority.length); dart.notNull(hostEnd)++) {
           if (authority.codeUnitAt(hostEnd) === _COLON) {
-            let portString = authority.substring(hostEnd + 1);
+            let portString = authority.substring(dart.notNull(hostEnd) + 1);
             if (portString.isNotEmpty)
               port = int.parse(portString);
             break;
           }
         }
         host = authority.substring(hostStart, hostEnd);
       }
       return new Uri({scheme: scheme, userInfo: userInfo, host: dart.as(host, String), port: dart.as(port, int), pathSegments: unencodedPath.split("/"), queryParameters: queryParameters});
     }
     Uri$file(path, opt$) {
@@ skipping 28 matching lines @@
         if (dart.dinvoke(segment, 'contains', new RegExp('["*/:<>?\\\\|]'))) {
           if (argumentError) {
             throw new ArgumentError("Illegal character in path");
           } else {
             throw new UnsupportedError("Illegal character in path");
           }
         }
       });
     }
     static [_checkWindowsDriveLetter](charCode, argumentError) {
-      if (dart.notNull(dart.notNull(_UPPER_CASE_A <= charCode) && dart.notNull(charCode <= _UPPER_CASE_Z)) || dart.notNull(dart.notNull(_LOWER_CASE_A <= charCode) && dart.notNull(charCode <= _LOWER_CASE_Z))) {
+      if (dart.notNull(_UPPER_CASE_A) <= dart.notNull(charCode) && dart.notNull(charCode) <= dart.notNull(_UPPER_CASE_Z) || dart.notNull(_LOWER_CASE_A) <= dart.notNull(charCode) && dart.notNull(charCode) <= dart.notNull(_LOWER_CASE_Z)) {
         return;
       }
       if (argumentError) {
         throw new ArgumentError(String['+']("Illegal drive letter ", new String.fromCharCode(charCode)));
       } else {
         throw new UnsupportedError(String['+']("Illegal drive letter ", new String.fromCharCode(charCode)));
       }
     }
     static [_makeFileUri](path) {
       let sep = "/";
       if (path.startsWith(sep)) {
         return new Uri({scheme: "file", pathSegments: path.split(sep)});
       } else {
         return new Uri({pathSegments: path.split(sep)});
       }
     }
     static [_makeWindowsFileUrl](path) {
       if (path.startsWith("\\\\?\\")) {
         if (path.startsWith("\\\\?\\UNC\\")) {
           path = `\\${path.substring(7)}`;
         } else {
           path = path.substring(4);
-          if (dart.notNull(dart.notNull(path.length < 3) || dart.notNull(path.codeUnitAt(1) !== _COLON)) || dart.notNull(path.codeUnitAt(2) !== _BACKSLASH)) {
+          if (dart.notNull(path.length) < 3 || path.codeUnitAt(1) !== _COLON || path.codeUnitAt(2) !== _BACKSLASH) {
             throw new ArgumentError("Windows paths with \\\\?\\ prefix must be absolute");
           }
         }
       } else {
         path = path.replaceAll("/", "\\");
       }
       let sep = "\\";
-      if (dart.notNull(path.length > 1) && dart.notNull(dart.equals(path.get(1), ":"))) {
+      if (dart.notNull(path.length) > 1 && dart.notNull(dart.equals(path.get(1), ":"))) {
         _checkWindowsDriveLetter(path.codeUnitAt(0), true);
-        if (dart.notNull(path.length === 2) || dart.notNull(path.codeUnitAt(2) !== _BACKSLASH)) {
+        if (path.length === 2 || path.codeUnitAt(2) !== _BACKSLASH) {
           throw new ArgumentError("Windows paths with drive letter must be absolute");
         }
         let pathSegments = path.split(sep);
         _checkWindowsPathReservedCharacters(pathSegments, true, 1);
         return new Uri({scheme: "file", pathSegments: pathSegments});
       }
-      if (dart.notNull(path.length > 0) && dart.notNull(dart.equals(path.get(0), sep))) {
-        if (dart.notNull(path.length > 1) && dart.notNull(dart.equals(path.get(1), sep))) {
+      if (dart.notNull(path.length) > 0 && dart.notNull(dart.equals(path.get(0), sep))) {
+        if (dart.notNull(path.length) > 1 && dart.notNull(dart.equals(path.get(1), sep))) {
           let pathStart = path.indexOf("\\", 2);
           let hostPart = pathStart === -1 ? path.substring(2) : path.substring(2, pathStart);
-          let pathPart = pathStart === -1 ? "" : path.substring(pathStart + 1);
+          let pathPart = pathStart === -1 ? "" : path.substring(dart.notNull(pathStart) + 1);
           let pathSegments = pathPart.split(sep);
           _checkWindowsPathReservedCharacters(pathSegments, true);
           return new Uri({scheme: "file", host: hostPart, pathSegments: pathSegments});
         } else {
           let pathSegments = path.split(sep);
           _checkWindowsPathReservedCharacters(pathSegments, true);
           return new Uri({scheme: "file", pathSegments: pathSegments});
         }
       } else {
         let pathSegments = path.split(sep);
@@ skipping 20 matching lines @@
       }
       let isFile = dart.equals(scheme, "file");
       if (userInfo !== null) {
         userInfo = _makeUserInfo(userInfo, 0, userInfo.length);
       } else {
         userInfo = this.userInfo;
       }
       if (port !== null) {
         port = _makePort(port, scheme);
       } else {
-        port = dart.notNull(this[_port]);
+        port = this[_port];
         if (schemeChanged) {
           port = _makePort(port, scheme);
         }
       }
       if (host !== null) {
         host = _makeHost(host, 0, host.length, false);
       } else if (this.hasAuthority) {
         host = this.host;
-      } else if (dart.notNull(dart.notNull(userInfo.isNotEmpty) || dart.notNull(port !== null)) || dart.notNull(isFile)) {
+      } else if (dart.notNull(userInfo.isNotEmpty) || port !== null || dart.notNull(isFile)) {
         host = "";
       }
       let ensureLeadingSlash = host !== null;
       if (dart.notNull(path !== null) || dart.notNull(pathSegments !== null)) {
         path = _makePath(path, 0, _stringOrNullLength(path), pathSegments, ensureLeadingSlash, isFile);
       } else {
         path = this.path;
-        if (dart.notNull(dart.notNull(isFile) || dart.notNull(dart.notNull(ensureLeadingSlash) && dart.notNull(!dart.notNull(path.isEmpty)))) && dart.notNull(!dart.notNull(path.startsWith('/')))) {
+        if ((dart.notNull(isFile) || dart.notNull(ensureLeadingSlash) && !dart.notNull(path.isEmpty)) && !dart.notNull(path.startsWith('/'))) {
           path = `/${path}`;
         }
       }
       if (dart.notNull(query !== null) || dart.notNull(queryParameters !== null)) {
         query = _makeQuery(query, 0, _stringOrNullLength(query), queryParameters);
       } else if (this.hasQuery) {
         query = this.query;
       }
       if (fragment !== null) {
         fragment = _makeFragment(fragment, 0, fragment.length);
       } else if (this.hasFragment) {
         fragment = this.fragment;
       }
       return new Uri._internal(scheme, userInfo, host, port, path, query, fragment);
     }
     get pathSegments() {
       if (this[_pathSegments] === null) {
-        let pathToSplit = dart.notNull(!dart.notNull(this.path.isEmpty)) && dart.notNull(this.path.codeUnitAt(0) === _SLASH) ? this.path.substring(1) : this.path;
+        let pathToSplit = !dart.notNull(this.path.isEmpty) && this.path.codeUnitAt(0) === _SLASH ? this.path.substring(1) : this.path;
         this[_pathSegments] = dart.as(new collection.UnmodifiableListView(dart.equals(pathToSplit, "") ? /* Unimplemented const */new List.from([]) : pathToSplit.split("/").map(Uri.decodeComponent).toList({growable: false})), List$(String));
       }
       return this[_pathSegments];
     }
     get queryParameters() {
       if (this[_queryParameters] === null) {
         this[_queryParameters] = dart.as(new collection.UnmodifiableMapView(splitQueryString(this.query)), Map$(String, String));
       }
       return this[_queryParameters];
     }
     static [_makePort](port, scheme) {
-      if (dart.notNull(port !== null) && dart.notNull(port === _defaultPort(scheme)))
-        return dart.as(null, int);
+      if (port !== null && port === _defaultPort(scheme))
+        return null;
       return port;
     }
     static [_makeHost](host, start, end, strictIPv6) {
       if (host === null)
         return null;
       if (start === end)
         return "";
       if (host.codeUnitAt(start) === _LEFT_BRACKET) {
-        if (host.codeUnitAt(end - 1) !== _RIGHT_BRACKET) {
+        if (host.codeUnitAt(dart.notNull(end) - 1) !== _RIGHT_BRACKET) {
           _fail(host, start, 'Missing end `]` to match `[` in host');
         }
-        parseIPv6Address(host, start + 1, end - 1);
+        parseIPv6Address(host, dart.notNull(start) + 1, dart.notNull(end) - 1);
         return host.substring(start, end).toLowerCase();
       }
       if (!dart.notNull(strictIPv6)) {
-        for (let i = start; i < end; i++) {
+        for (let i = start; dart.notNull(i) < dart.notNull(end); dart.notNull(i)++) {
           if (host.codeUnitAt(i) === _COLON) {
             parseIPv6Address(host, start, end);
             return `[${host}]`;
           }
         }
       }
       return _normalizeRegName(host, start, end);
     }
     static [_isRegNameChar](char) {
-      return dart.notNull(char < 127) && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_regNameTable, char >> 4), '&', 1 << (char & 15)), 0));
+      return dart.notNull(char) < 127 && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_regNameTable, dart.notNull(char) >> 4), '&', 1 << (dart.notNull(char) & 15)), 0));
     }
     static [_normalizeRegName](host, start, end) {
       let buffer = null;
       let sectionStart = start;
       let index = start;
       let isNormalized = true;
-      while (index < end) {
+      while (dart.notNull(index) < dart.notNull(end)) {
         let char = host.codeUnitAt(index);
         if (char === _PERCENT) {
           let replacement = _normalizeEscape(host, index, true);
           if (dart.notNull(replacement === null) && dart.notNull(isNormalized)) {
             index = 3;
             continue;
           }
           if (buffer === null)
             buffer = new StringBuffer();
           let slice = host.substring(sectionStart, index);
           if (!dart.notNull(isNormalized))
             slice = slice.toLowerCase();
           buffer.write(slice);
           let sourceLength = 3;
           if (replacement === null) {
-            replacement = host.substring(index, index + 3);
+            replacement = host.substring(index, dart.notNull(index) + 3);
           } else if (dart.equals(replacement, "%")) {
             replacement = "%25";
             sourceLength = 1;
           }
           buffer.write(replacement);
           index = sourceLength;
           sectionStart = index;
           isNormalized = true;
         } else if (_isRegNameChar(char)) {
-          if (dart.notNull(dart.notNull(isNormalized) && dart.notNull(_UPPER_CASE_A <= char)) && dart.notNull(_UPPER_CASE_Z >= char)) {
+          if (dart.notNull(isNormalized) && dart.notNull(_UPPER_CASE_A) <= dart.notNull(char) && dart.notNull(_UPPER_CASE_Z) >= dart.notNull(char)) {
             if (buffer === null)
               buffer = new StringBuffer();
-            if (sectionStart < index) {
+            if (dart.notNull(sectionStart) < dart.notNull(index)) {
               buffer.write(host.substring(sectionStart, index));
               sectionStart = index;
             }
             isNormalized = false;
           }
-          index++;
+          dart.notNull(index)++;
         } else if (_isGeneralDelimiter(char)) {
           _fail(host, index, "Invalid character");
         } else {
           let sourceLength = 1;
-          if (dart.notNull((char & 64512) === 55296) && dart.notNull(index + 1 < end)) {
-            let tail = host.codeUnitAt(index + 1);
-            if ((tail & 64512) === 56320) {
-              char = 65536 | (char & 1023) << 10 | tail & 1023;
+          if ((dart.notNull(char) & 64512) === 55296 && dart.notNull(index) + 1 < dart.notNull(end)) {
+            let tail = host.codeUnitAt(dart.notNull(index) + 1);
+            if ((dart.notNull(tail) & 64512) === 56320) {
+              char = 65536 | (dart.notNull(char) & 1023) << 10 | dart.notNull(tail) & 1023;
               sourceLength = 2;
             }
           }
           if (buffer === null)
             buffer = new StringBuffer();
           let slice = host.substring(sectionStart, index);
           if (!dart.notNull(isNormalized))
             slice = slice.toLowerCase();
           buffer.write(slice);
           buffer.write(_escapeChar(char));
           index = sourceLength;
           sectionStart = index;
         }
       }
       if (buffer === null)
         return host.substring(start, end);
-      if (sectionStart < end) {
+      if (dart.notNull(sectionStart) < dart.notNull(end)) {
         let slice = host.substring(sectionStart, end);
         if (!dart.notNull(isNormalized))
           slice = slice.toLowerCase();
         buffer.write(slice);
       }
       return buffer.toString();
     }
     static [_makeScheme](scheme, end) {
       if (end === 0)
         return "";
       let firstCodeUnit = scheme.codeUnitAt(0);
       if (!dart.notNull(_isAlphabeticCharacter(firstCodeUnit))) {
         _fail(scheme, 0, "Scheme not starting with alphabetic character");
       }
-      let allLowercase = firstCodeUnit >= _LOWER_CASE_A;
-      for (let i = 0; i < end; i++) {
+      let allLowercase = dart.notNull(firstCodeUnit) >= dart.notNull(_LOWER_CASE_A);
+      for (let i = 0; dart.notNull(i) < dart.notNull(end); dart.notNull(i)++) {
         let codeUnit = scheme.codeUnitAt(i);
         if (!dart.notNull(_isSchemeCharacter(codeUnit))) {
           _fail(scheme, i, "Illegal scheme character");
         }
-        if (dart.notNull(codeUnit < _LOWER_CASE_A) || dart.notNull(codeUnit > _LOWER_CASE_Z)) {
+        if (dart.notNull(codeUnit) < dart.notNull(_LOWER_CASE_A) || dart.notNull(codeUnit) > dart.notNull(_LOWER_CASE_Z)) {
           allLowercase = false;
         }
       }
       scheme = scheme.substring(0, end);
       if (!dart.notNull(allLowercase))
         scheme = scheme.toLowerCase();
       return scheme;
     }
     static [_makeUserInfo](userInfo, start, end) {
       if (userInfo === null)
         return "";
       return _normalize(userInfo, start, end, dart.as(_userinfoTable, List$(int)));
     }
     static [_makePath](path, start, end, pathSegments, ensureLeadingSlash, isFile) {
       if (dart.notNull(path === null) && dart.notNull(pathSegments === null))
         return isFile ? "/" : "";
       if (dart.notNull(path !== null) && dart.notNull(pathSegments !== null)) {
         throw new ArgumentError('Both path and pathSegments specified');
       }
       let result = null;
       if (path !== null) {
         result = _normalize(path, start, end, dart.as(_pathCharOrSlashTable, List$(int)));
       } else {
         result = pathSegments.map((s) => _uriEncode(dart.as(_pathCharTable, List$(int)), dart.as(s, String))).join("/");
       }
       if (dart.dload(result, 'isEmpty')) {
         if (isFile)
           return "/";
-      } else if (dart.notNull(dart.notNull(isFile) || dart.notNull(ensureLeadingSlash)) && dart.notNull(!dart.equals(dart.dinvoke(result, 'codeUnitAt', 0), _SLASH))) {
+      } else if ((dart.notNull(isFile) || dart.notNull(ensureLeadingSlash)) && dart.notNull(!dart.equals(dart.dinvoke(result, 'codeUnitAt', 0), _SLASH))) {
         return `/${result}`;
       }
       return dart.as(result, String);
     }
     static [_makeQuery](query, start, end, queryParameters) {
       if (dart.notNull(query === null) && dart.notNull(queryParameters === null))
         return null;
       if (dart.notNull(query !== null) && dart.notNull(queryParameters !== null)) {
         throw new ArgumentError('Both query and queryParameters specified');
       }
@@ skipping 16 matching lines @@
     }
     static [_makeFragment](fragment, start, end) {
       if (fragment === null)
         return null;
       return _normalize(fragment, start, end, dart.as(_queryCharTable, List$(int)));
     }
     static [_stringOrNullLength](s) {
       return s === null ? 0 : s.length;
     }
     static [_isHexDigit](char) {
-      if (_NINE >= char)
-        return _ZERO <= char;
+      if (dart.notNull(_NINE) >= dart.notNull(char))
+        return dart.notNull(_ZERO) <= dart.notNull(char);
       char = 32;
-      return dart.notNull(_LOWER_CASE_A <= char) && dart.notNull(_LOWER_CASE_F >= char);
+      return dart.notNull(_LOWER_CASE_A) <= dart.notNull(char) && dart.notNull(_LOWER_CASE_F) >= dart.notNull(char);
     }
     static [_hexValue](char) {
       dart.assert(_isHexDigit(char));
-      if (_NINE >= char)
-        return char - _ZERO;
+      if (dart.notNull(_NINE) >= dart.notNull(char))
+        return dart.notNull(char) - dart.notNull(_ZERO);
       char = 32;
-      return char - (_LOWER_CASE_A - 10);
+      return dart.notNull(char) - (dart.notNull(_LOWER_CASE_A) - 10);
     }
     static [_normalizeEscape](source, index, lowerCase) {
       dart.assert(source.codeUnitAt(index) === _PERCENT);
-      if (index + 2 >= source.length) {
+      if (dart.notNull(index) + 2 >= dart.notNull(source.length)) {
         return "%";
       }
-      let firstDigit = source.codeUnitAt(index + 1);
-      let secondDigit = source.codeUnitAt(index + 2);
-      if (dart.notNull(!dart.notNull(_isHexDigit(firstDigit))) || dart.notNull(!dart.notNull(_isHexDigit(secondDigit)))) {
+      let firstDigit = source.codeUnitAt(dart.notNull(index) + 1);
+      let secondDigit = source.codeUnitAt(dart.notNull(index) + 2);
+      if (!dart.notNull(_isHexDigit(firstDigit)) || !dart.notNull(_isHexDigit(secondDigit))) {
         return "%";
       }
-      let value = _hexValue(firstDigit) * 16 + _hexValue(secondDigit);
+      let value = dart.notNull(_hexValue(firstDigit)) * 16 + dart.notNull(_hexValue(secondDigit));
       if (_isUnreservedChar(value)) {
-        if (dart.notNull(dart.notNull(lowerCase) && dart.notNull(_UPPER_CASE_A <= value)) && dart.notNull(_UPPER_CASE_Z >= value)) {
+        if (dart.notNull(lowerCase) && dart.notNull(_UPPER_CASE_A) <= dart.notNull(value) && dart.notNull(_UPPER_CASE_Z) >= dart.notNull(value)) {
           value = 32;
         }
         return new String.fromCharCode(value);
       }
-      if (dart.notNull(firstDigit >= _LOWER_CASE_A) || dart.notNull(secondDigit >= _LOWER_CASE_A)) {
-        return source.substring(index, index + 3).toUpperCase();
+      if (dart.notNull(firstDigit) >= dart.notNull(_LOWER_CASE_A) || dart.notNull(secondDigit) >= dart.notNull(_LOWER_CASE_A)) {
+        return source.substring(index, dart.notNull(index) + 3).toUpperCase();
       }
       return null;
     }
     static [_isUnreservedChar](ch) {
-      return dart.notNull(ch < 127) && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_unreservedTable, ch >> 4), '&', 1 << (ch & 15)), 0));
+      return dart.notNull(ch) < 127 && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_unreservedTable, dart.notNull(ch) >> 4), '&', 1 << (dart.notNull(ch) & 15)), 0));
     }
     static [_escapeChar](char) {
       dart.assert(dart.dbinary(char, '<=', 1114111));
       let hexDigits = "0123456789ABCDEF";
       let codeUnits = null;
       if (dart.dbinary(char, '<', 128)) {
         codeUnits = new List(3);
         codeUnits.set(0, _PERCENT);
         codeUnits.set(1, hexDigits.codeUnitAt(dart.as(dart.dbinary(char, '>>', 4), int)));
         codeUnits.set(2, hexDigits.codeUnitAt(dart.as(dart.dbinary(char, '&', 15), int)));
       } else {
         let flag = 192;
         let encodedBytes = 2;
         if (dart.dbinary(char, '>', 2047)) {
           flag = 224;
           encodedBytes = 3;
           if (dart.dbinary(char, '>', 65535)) {
             encodedBytes = 4;
             flag = 240;
           }
         }
-        codeUnits = new List(3 * encodedBytes);
+        codeUnits = new List(3 * dart.notNull(encodedBytes));
         let index = 0;
-        while (--encodedBytes >= 0) {
-          let byte = dart.as(dart.dbinary(dart.dbinary(dart.dbinary(char, '>>', 6 * encodedBytes), '&', 63), '|', flag), int);
+        while (--dart.notNull(encodedBytes) >= 0) {
+          let byte = dart.as(dart.dbinary(dart.dbinary(dart.dbinary(char, '>>', 6 * dart.notNull(encodedBytes)), '&', 63), '|', flag), int);
           codeUnits.set(index, _PERCENT);
-          codeUnits.set(index + 1, hexDigits.codeUnitAt(byte >> 4));
-          codeUnits.set(index + 2, hexDigits.codeUnitAt(byte & 15));
+          codeUnits.set(dart.notNull(index) + 1, hexDigits.codeUnitAt(dart.notNull(byte) >> 4));
+          codeUnits.set(dart.notNull(index) + 2, hexDigits.codeUnitAt(dart.notNull(byte) & 15));
           index = 3;
           flag = 128;
         }
       }
       return new String.fromCharCodes(dart.as(codeUnits, Iterable$(int)));
     }
     static [_normalize](component, start, end, charTable) {
       let buffer = null;
       let sectionStart = start;
       let index = start;
-      while (index < end) {
+      while (dart.notNull(index) < dart.notNull(end)) {
         let char = component.codeUnitAt(index);
-        if (dart.notNull(char < 127) && dart.notNull((charTable.get(char >> 4) & 1 << (char & 15)) !== 0)) {
-          index++;
+        if (dart.notNull(char) < 127 && (dart.notNull(charTable.get(dart.notNull(char) >> 4)) & 1 << (dart.notNull(char) & 15)) !== 0) {
+          dart.notNull(index)++;
         } else {
           let replacement = null;
           let sourceLength = null;
           if (char === _PERCENT) {
             replacement = _normalizeEscape(component, index, false);
             if (replacement === null) {
               index = 3;
               continue;
             }
             if (dart.equals("%", replacement)) {
               replacement = "%25";
               sourceLength = 1;
             } else {
               sourceLength = 3;
             }
           } else if (_isGeneralDelimiter(char)) {
             _fail(component, index, "Invalid character");
           } else {
             sourceLength = 1;
-            if ((char & 64512) === 55296) {
-              if (index + 1 < end) {
-                let tail = component.codeUnitAt(index + 1);
-                if ((tail & 64512) === 56320) {
+            if ((dart.notNull(char) & 64512) === 55296) {
+              if (dart.notNull(index) + 1 < dart.notNull(end)) {
+                let tail = component.codeUnitAt(dart.notNull(index) + 1);
+                if ((dart.notNull(tail) & 64512) === 56320) {
                   sourceLength = 2;
-                  char = 65536 | (char & 1023) << 10 | tail & 1023;
+                  char = 65536 | (dart.notNull(char) & 1023) << 10 | dart.notNull(tail) & 1023;
                 }
               }
             }
             replacement = _escapeChar(char);
           }
           if (buffer === null)
             buffer = new StringBuffer();
           buffer.write(component.substring(sectionStart, index));
           buffer.write(replacement);
           index = sourceLength;
           sectionStart = index;
         }
       }
       if (buffer === null) {
         return component.substring(start, end);
       }
-      if (sectionStart < end) {
+      if (dart.notNull(sectionStart) < dart.notNull(end)) {
         buffer.write(component.substring(sectionStart, end));
       }
       return buffer.toString();
     }
     static [_isSchemeCharacter](ch) {
-      return dart.notNull(ch < 128) && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_schemeTable, ch >> 4), '&', 1 << (ch & 15)), 0));
+      return dart.notNull(ch) < 128 && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_schemeTable, dart.notNull(ch) >> 4), '&', 1 << (dart.notNull(ch) & 15)), 0));
     }
     static [_isGeneralDelimiter](ch) {
-      return dart.notNull(ch <= _RIGHT_BRACKET) && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_genDelimitersTable, ch >> 4), '&', 1 << (ch & 15)), 0));
+      return dart.notNull(ch) <= dart.notNull(_RIGHT_BRACKET) && dart.notNull(!dart.equals(dart.dbinary(dart.dindex(_genDelimitersTable, dart.notNull(ch) >> 4), '&', 1 << (dart.notNull(ch) & 15)), 0));
     }
     get isAbsolute() {
       return dart.notNull(!dart.equals(this.scheme, "")) && dart.notNull(dart.equals(this.fragment, ""));
     }
     [_merge](base, reference) {
       if (base.isEmpty)
         return `/${reference}`;
       let backCount = 0;
       let refStart = 0;
       while (reference.startsWith("../", refStart)) {
         refStart = 3;
-        backCount++;
+        dart.notNull(backCount)++;
       }
       let baseEnd = base.lastIndexOf('/');
-      while (dart.notNull(baseEnd > 0) && dart.notNull(backCount > 0)) {
-        let newEnd = base.lastIndexOf('/', baseEnd - 1);
-        if (newEnd < 0) {
+      while (dart.notNull(baseEnd) > 0 && dart.notNull(backCount) > 0) {
+        let newEnd = base.lastIndexOf('/', dart.notNull(baseEnd) - 1);
+        if (dart.notNull(newEnd) < 0) {
           break;
         }
-        let delta = baseEnd - newEnd;
-        if (dart.notNull(dart.notNull(dart.notNull(delta === 2) || dart.notNull(delta === 3)) && dart.notNull(base.codeUnitAt(newEnd + 1) === _DOT)) && dart.notNull(dart.notNull(delta === 2) || dart.notNull(base.codeUnitAt(newEnd + 2) === _DOT))) {
+        let delta = dart.notNull(baseEnd) - dart.notNull(newEnd);
+        if ((delta === 2 || delta === 3) && base.codeUnitAt(dart.notNull(newEnd) + 1) === _DOT && (delta === 2 || base.codeUnitAt(dart.notNull(newEnd) + 2) === _DOT)) {
           break;
         }
         baseEnd = newEnd;
-        backCount--;
+        dart.notNull(backCount)--;
       }
-      return String['+'](base.substring(0, baseEnd + 1), reference.substring(refStart - 3 * backCount));
+      return String['+'](base.substring(0, dart.notNull(baseEnd) + 1), reference.substring(dart.notNull(refStart) - 3 * dart.notNull(backCount)));
     }
     [_hasDotSegments](path) {
-      if (dart.notNull(path.length > 0) && dart.notNull(path.codeUnitAt(0) === _DOT))
+      if (dart.notNull(path.length) > 0 && path.codeUnitAt(0) === _DOT)
         return true;
       let index = path.indexOf("/.");
       return index !== -1;
     }
     [_removeDotSegments](path) {
       if (!dart.notNull(this[_hasDotSegments](path)))
         return path;
       let output = dart.as(new List.from([]), List$(String));
       let appendSlash = false;
       for (let segment of path.split("/")) {
         appendSlash = false;
         if (dart.equals(segment, "..")) {
-          if (dart.notNull(!dart.notNull(output.isEmpty)) && dart.notNull(dart.notNull(output.length !== 1) || dart.notNull(!dart.equals(output.get(0), ""))))
+          if (!dart.notNull(output.isEmpty) && (output.length !== 1 || dart.notNull(!dart.equals(output.get(0), ""))))
             output.removeLast();
           appendSlash = true;
         } else if (dart.equals(".", segment)) {
           appendSlash = true;
         } else {
           output.add(segment);
         }
       }
       if (appendSlash)
         output.add("");
@@ skipping 41 matching lines @@
             if (reference.path.startsWith("/")) {
               targetPath = this[_removeDotSegments](reference.path);
             } else {
               targetPath = this[_removeDotSegments](this[_merge](this[_path], reference.path));
             }
             if (reference.hasQuery)
               targetQuery = reference.query;
           }
           targetUserInfo = this[_userInfo];
           targetHost = this[_host];
-          targetPort = dart.notNull(this[_port]);
+          targetPort = this[_port];
         }
       }
       let fragment = dart.as(reference.hasFragment ? reference.fragment : null, String);
       return new Uri._internal(targetScheme, targetUserInfo, targetHost, targetPort, targetPath, targetQuery, fragment);
     }
     get hasAuthority() {
       return this[_host] !== null;
     }
     get hasPort() {
       return this[_port] !== null;
     }
     get hasQuery() {
       return this[_query] !== null;
     }
     get hasFragment() {
       return this[_fragment] !== null;
     }
     get origin() {
-      if (dart.notNull(dart.notNull(dart.equals(this.scheme, "")) || dart.notNull(this[_host] === null)) || dart.notNull(dart.equals(this[_host], ""))) {
+      if (dart.notNull(dart.equals(this.scheme, "")) || dart.notNull(this[_host] === null) || dart.notNull(dart.equals(this[_host], ""))) {
         throw new StateError(`Cannot use origin without a scheme: ${this}`);
       }
       if (dart.notNull(!dart.equals(this.scheme, "http")) && dart.notNull(!dart.equals(this.scheme, "https"))) {
         throw new StateError(`Origin is only applicable schemes http and https: ${this}`);
       }
       if (this[_port] === null)
         return `${this.scheme}://${this[_host]}`;
       return `${this.scheme}://${this[_host]}:${this[_port]}`;
     }
     toFilePath(opt$) {
@@ skipping 18 matching lines @@
       _checkNonWindowsPathReservedCharacters(this.pathSegments, false);
       let result = new StringBuffer();
       if (this[_isPathAbsolute])
         result.write("/");
       result.writeAll(this.pathSegments, "/");
       return result.toString();
     }
     [_toWindowsFilePath]() {
       let hasDriveLetter = false;
       let segments = this.pathSegments;
-      if (dart.notNull(dart.notNull(segments.length > 0) && dart.notNull(segments.get(0).length === 2)) && dart.notNull(segments.get(0).codeUnitAt(1) === _COLON)) {
+      if (dart.notNull(segments.length) > 0 && segments.get(0).length === 2 && segments.get(0).codeUnitAt(1) === _COLON) {
         _checkWindowsDriveLetter(segments.get(0).codeUnitAt(0), false);
         _checkWindowsPathReservedCharacters(segments, false, 1);
         hasDriveLetter = true;
       } else {
         _checkWindowsPathReservedCharacters(segments, false);
       }
       let result = new StringBuffer();
-      if (dart.notNull(this[_isPathAbsolute]) && dart.notNull(!dart.notNull(hasDriveLetter)))
+      if (dart.notNull(this[_isPathAbsolute]) && !dart.notNull(hasDriveLetter))
         result.write("\\");
       if (!dart.equals(this.host, "")) {
         result.write("\\");
         result.write(this.host);
         result.write("\\");
       }
       result.writeAll(segments, "\\");
-      if (dart.notNull(hasDriveLetter) && dart.notNull(segments.length === 1))
+      if (dart.notNull(hasDriveLetter) && segments.length === 1)
         result.write("\\");
       return result.toString();
     }
     get [_isPathAbsolute]() {
       if (dart.notNull(this.path === null) || dart.notNull(this.path.isEmpty))
         return false;
       return this.path.startsWith('/');
     }
     [_writeAuthority](ss) {
       if (this[_userInfo].isNotEmpty) {
         ss.write(this[_userInfo]);
         ss.write("@");
       }
       if (this[_host] !== null)
         ss.write(this[_host]);
       if (this[_port] !== null) {
         ss.write(":");
         ss.write(this[_port]);
       }
     }
     toString() {
       let sb = new StringBuffer();
       _addIfNonEmpty(sb, this.scheme, this.scheme, ':');
-      if (dart.notNull(dart.notNull(this.hasAuthority) || dart.notNull(this.path.startsWith("//"))) || dart.notNull(dart.equals(this.scheme, "file"))) {
+      if (dart.notNull(this.hasAuthority) || dart.notNull(this.path.startsWith("//")) || dart.notNull(dart.equals(this.scheme, "file"))) {
         sb.write("//");
         this[_writeAuthority](sb);
       }
       sb.write(this.path);
       if (this[_query] !== null) {
         sb.write("?");
         sb.write(this[_query]);
       }
       if (this[_fragment] !== null) {
         sb.write("#");
         sb.write(this[_fragment]);
       }
       return sb.toString();
     }
     ['=='](other) {
       if (!dart.is(other, Uri))
         return false;
       let uri = dart.as(other, Uri);
-      return dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.equals(this.scheme, uri.scheme)) && dart.notNull(this.hasAuthority === uri.hasAuthority)) && dart.notNull(dart.equals(this.userInfo, uri.userInfo))) && dart.notNull(dart.equals(this.host, uri.host))) && dart.notNull(this.port === uri.port)) && dart.notNull(dart.equals(this.path, uri.path))) && dart.notNull(this.hasQuery === uri.hasQuery)) && dart.notNull(dart.equals(this.query, uri.query))) && dart.notNull(this.hasFragment === uri.hasFragment)) && dart.notNull(dart.equals(this.fragment, uri.fragment));
+      return dart.notNull(dart.equals(this.scheme, uri.scheme)) && this.hasAuthority === uri.hasAuthority && dart.notNull(dart.equals(this.userInfo, uri.userInfo)) && dart.notNull(dart.equals(this.host, uri.host)) && this.port === uri.port && dart.notNull(dart.equals(this.path, uri.path)) && this.hasQuery === uri.hasQuery && dart.notNull(dart.equals(this.query, uri.query)) && this.hasFragment === uri.hasFragment && dart.notNull(dart.equals(this.fragment, uri.fragment));
     }
     get hashCode() {
       // Function combine: (dynamic, dynamic) → int
       function combine(part, current) {
         return dart.as(dart.dbinary(dart.dbinary(dart.dbinary(current, '*', 31), '+', dart.dload(part, 'hashCode')), '&', 1073741823), int);
       }
       return combine(this.scheme, combine(this.userInfo, combine(this.host, combine(this.port, combine(this.path, combine(this.query, combine(this.fragment, 1)))))));
     }
     static [_addIfNonEmpty](sb, test, first, second) {
       if (!dart.equals("", test)) {
@@ skipping 24 matching lines @@
     static splitQueryString(query, opt$) {
       let encoding = opt$.encoding === void 0 ? convert.UTF8 : opt$.encoding;
       return dart.as(query.split("&").fold(dart.map(), (map, element) => {
         let index = dart.as(dart.dinvoke(element, 'indexOf', "="), int);
         if (index === -1) {
           if (!dart.equals(element, "")) {
             dart.dsetindex(map, decodeQueryComponent(dart.as(element, String), {encoding: encoding}), "");
           }
         } else if (index !== 0) {
           let key = dart.dinvoke(element, 'substring', 0, index);
-          let value = dart.dinvoke(element, 'substring', index + 1);
+          let value = dart.dinvoke(element, 'substring', dart.notNull(index) + 1);
           dart.dsetindex(map, Uri.decodeQueryComponent(dart.as(key, String), {encoding: encoding}), decodeQueryComponent(dart.as(value, String), {encoding: encoding}));
         }
         return map;
       }), Map$(String, String));
     }
     static parseIPv4Address(host) {
       // Function error: (String) → void
       function error(msg) {
         throw new FormatException(`Illegal IPv4 address, ${msg}`);
       }
       let bytes = host.split('.');
       if (bytes.length !== 4) {
         error('IPv4 address should contain exactly 4 parts');
       }
       return dart.as(bytes.map((byteString) => {
         let byte = int.parse(dart.as(byteString, String));
-        if (dart.notNull(byte < 0) || dart.notNull(byte > 255)) {
+        if (dart.notNull(byte) < 0 || dart.notNull(byte) > 255) {
           error('each part must be in the range of `0..255`');
         }
         return byte;
       }).toList(), List$(int));
     }
     static parseIPv6Address(host, start, end) {
       if (start === void 0)
         start = 0;
       if (end === void 0)
         end = null;
       if (end === null)
         end = host.length;
       // Function error: (String, [dynamic]) → void
       function error(msg, position) {
         if (position === void 0)
           position = null;
         throw new FormatException(`Illegal IPv6 address, ${msg}`, host, dart.as(position, int));
       }
       // Function parseHex: (int, int) → int
       function parseHex(start, end) {
-        if (end - start > 4) {
+        if (dart.notNull(end) - dart.notNull(start) > 4) {
           error('an IPv6 part can only contain a maximum of 4 hex digits', start);
         }
         let value = int.parse(host.substring(start, end), {radix: 16});
-        if (dart.notNull(value < 0) || dart.notNull(value > (1 << 16) - 1)) {
+        if (dart.notNull(value) < 0 || dart.notNull(value) > (1 << 16) - 1) {
           error('each part must be in the range of `0x0..0xFFFF`', start);
         }
         return value;
       }
-      if (host.length < 2)
+      if (dart.notNull(host.length) < 2)
         error('address is too short');
       let parts = dart.as(new List.from([]), List$(int));
       let wildcardSeen = false;
       let partStart = start;
-      for (let i = start; i < end; i++) {
+      for (let i = start; dart.notNull(i) < dart.notNull(end); dart.notNull(i)++) {
         if (host.codeUnitAt(i) === _COLON) {
           if (i === start) {
-            i++;
+            dart.notNull(i)++;
             if (host.codeUnitAt(i) !== _COLON) {
               error('invalid start colon.', i);
             }
             partStart = i;
           }
           if (i === partStart) {
             if (wildcardSeen) {
               error('only one wildcard `::` is allowed', i);
             }
             wildcardSeen = true;
             parts.add(-1);
           } else {
             parts.add(parseHex(partStart, i));
           }
-          partStart = i + 1;
+          partStart = dart.notNull(i) + 1;
         }
       }
       if (parts.length === 0)
         error('too few parts');
       let atEnd = partStart === end;
       let isLastWildcard = parts.last === -1;
-      if (dart.notNull(atEnd) && dart.notNull(!dart.notNull(isLastWildcard))) {
+      if (dart.notNull(atEnd) && !dart.notNull(isLastWildcard)) {
         error('expected a part after last `:`', end);
       }
       if (!dart.notNull(atEnd)) {
         try {
           parts.add(parseHex(partStart, end));
         } catch (e) {
           try {
             let last = parseIPv4Address(host.substring(partStart, end));
-            parts.add(last.get(0) << 8 | last.get(1));
-            parts.add(last.get(2) << 8 | last.get(3));
+            parts.add(dart.notNull(last.get(0)) << 8 | dart.notNull(last.get(1)));
+            parts.add(dart.notNull(last.get(2)) << 8 | dart.notNull(last.get(3)));
           } catch (e) {
             error('invalid end of IPv6 address.', partStart);
           }
 
         }
 
       }
       if (wildcardSeen) {
-        if (parts.length > 7) {
+        if (dart.notNull(parts.length) > 7) {
           error('an address with a wildcard must have less than 7 parts');
         }
       } else if (parts.length !== 8) {
         error('an address without a wildcard must contain exactly 8 parts');
       }
       let bytes = new List(16);
-      for (let i = 0, index = 0; i < parts.length; i++) {
+      for (let i = 0, index = 0; dart.notNull(i) < dart.notNull(parts.length); dart.notNull(i)++) {
         let value = parts.get(i);
         if (value === -1) {
-          let wildCardLength = 9 - parts.length;
-          for (let j = 0; j < wildCardLength; j++) {
+          let wildCardLength = 9 - dart.notNull(parts.length);
+          for (let j = 0; dart.notNull(j) < dart.notNull(wildCardLength); dart.notNull(j)++) {
             bytes.set(index, 0);
-            bytes.set(index + 1, 0);
+            bytes.set(dart.notNull(index) + 1, 0);
             index = 2;
           }
         } else {
-          bytes.set(index, value >> 8);
-          bytes.set(index + 1, value & 255);
+          bytes.set(index, dart.notNull(value) >> 8);
+          bytes.set(dart.notNull(index) + 1, dart.notNull(value) & 255);
           index = 2;
         }
       }
       return dart.as(bytes, List$(int));
     }
     static [_uriEncode](canonicalTable, text, opt$) {
       let encoding = opt$.encoding === void 0 ? convert.UTF8 : opt$.encoding;
       let spaceToPlus = opt$.spaceToPlus === void 0 ? false : opt$.spaceToPlus;
       // Function byteToHex: (dynamic, dynamic) → dynamic
       function byteToHex(byte, buffer) {
         let hex = '0123456789ABCDEF';
         dart.dinvoke(buffer, 'writeCharCode', hex.codeUnitAt(dart.as(dart.dbinary(byte, '>>', 4), int)));
         dart.dinvoke(buffer, 'writeCharCode', hex.codeUnitAt(dart.as(dart.dbinary(byte, '&', 15), int)));
       }
       let result = new StringBuffer();
       let bytes = encoding.encode(text);
-      for (let i = 0; i < bytes.length; i++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(bytes.length); dart.notNull(i)++) {
         let byte = bytes.get(i);
-        if (dart.notNull(byte < 128) && dart.notNull((canonicalTable.get(byte >> 4) & 1 << (byte & 15)) !== 0)) {
+        if (dart.notNull(byte) < 128 && (dart.notNull(canonicalTable.get(dart.notNull(byte) >> 4)) & 1 << (dart.notNull(byte) & 15)) !== 0) {
           result.writeCharCode(byte);
-        } else if (dart.notNull(spaceToPlus) && dart.notNull(byte === _SPACE)) {
+        } else if (dart.notNull(spaceToPlus) && byte === _SPACE) {
           result.writeCharCode(_PLUS);
         } else {
           result.writeCharCode(_PERCENT);
           byteToHex(byte, result);
         }
       }
       return result.toString();
     }
     static [_hexCharPairToByte](s, pos) {
       let byte = 0;
-      for (let i = 0; i < 2; i++) {
-        let charCode = s.codeUnitAt(pos + i);
-        if (dart.notNull(48 <= charCode) && dart.notNull(charCode <= 57)) {
-          byte = byte * 16 + charCode - 48;
+      for (let i = 0; dart.notNull(i) < 2; dart.notNull(i)++) {
+        let charCode = s.codeUnitAt(dart.notNull(pos) + dart.notNull(i));
+        if (48 <= dart.notNull(charCode) && dart.notNull(charCode) <= 57) {
+          byte = dart.notNull(byte) * 16 + dart.notNull(charCode) - 48;
         } else {
           charCode = 32;
-          if (dart.notNull(97 <= charCode) && dart.notNull(charCode <= 102)) {
-            byte = byte * 16 + charCode - 87;
+          if (97 <= dart.notNull(charCode) && dart.notNull(charCode) <= 102) {
+            byte = dart.notNull(byte) * 16 + dart.notNull(charCode) - 87;
           } else {
             throw new ArgumentError("Invalid URL encoding");
           }
         }
       }
       return byte;
     }
     static [_uriDecode](text, opt$) {
       let plusToSpace = opt$.plusToSpace === void 0 ? false : opt$.plusToSpace;
       let encoding = opt$.encoding === void 0 ? convert.UTF8 : opt$.encoding;
       let simple = true;
-      for (let i = 0; dart.notNull(i < text.length) && dart.notNull(simple); i++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(text.length) && dart.notNull(simple); dart.notNull(i)++) {
         let codeUnit = text.codeUnitAt(i);
-        simple = dart.notNull(codeUnit !== _PERCENT) && dart.notNull(codeUnit !== _PLUS);
+        simple = codeUnit !== _PERCENT && codeUnit !== _PLUS;
       }
       let bytes = null;
       if (simple) {
         if (dart.notNull(dart.equals(encoding, convert.UTF8)) || dart.notNull(dart.equals(encoding, convert.LATIN1))) {
           return text;
         } else {
           bytes = text.codeUnits;
         }
       } else {
         bytes = dart.as(new List(), List$(int));
-        for (let i = 0; i < text.length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(text.length); dart.notNull(i)++) {
           let codeUnit = text.codeUnitAt(i);
-          if (codeUnit > 127) {
+          if (dart.notNull(codeUnit) > 127) {
             throw new ArgumentError("Illegal percent encoding in URI");
           }
           if (codeUnit === _PERCENT) {
-            if (i + 3 > text.length) {
+            if (dart.notNull(i) + 3 > dart.notNull(text.length)) {
               throw new ArgumentError('Truncated URI');
             }
-            bytes.add(_hexCharPairToByte(text, i + 1));
+            bytes.add(_hexCharPairToByte(text, dart.notNull(i) + 1));
             i = 2;
-          } else if (dart.notNull(plusToSpace) && dart.notNull(codeUnit === _PLUS)) {
+          } else if (dart.notNull(plusToSpace) && codeUnit === _PLUS) {
             bytes.add(_SPACE);
           } else {
             bytes.add(codeUnit);
           }
         }
       }
       return encoding.decode(bytes);
     }
     static [_isAlphabeticCharacter](codeUnit) {
-      return dart.notNull(dart.notNull(codeUnit >= _LOWER_CASE_A) && dart.notNull(codeUnit <= _LOWER_CASE_Z)) || dart.notNull(dart.notNull(codeUnit >= _UPPER_CASE_A) && dart.notNull(codeUnit <= _UPPER_CASE_Z));
+      return dart.notNull(codeUnit) >= dart.notNull(_LOWER_CASE_A) && dart.notNull(codeUnit) <= dart.notNull(_LOWER_CASE_Z) || dart.notNull(codeUnit) >= dart.notNull(_UPPER_CASE_A) && dart.notNull(codeUnit) <= dart.notNull(_UPPER_CASE_Z);
     }
   }
   dart.defineNamedConstructor(Uri, '_internal');
   dart.defineNamedConstructor(Uri, 'http');
   dart.defineNamedConstructor(Uri, 'https');
   dart.defineNamedConstructor(Uri, 'file');
   Uri._SPACE = 32;
   Uri._DOUBLE_QUOTE = 34;
   Uri._NUMBER_SIGN = 35;
   Uri._PERCENT = 37;
@@ skipping 94 matching lines @@
   exports.Stopwatch = Stopwatch;
   exports.String = String;
   exports.Runes = Runes;
   exports.RuneIterator = RuneIterator;
   exports.StringBuffer = StringBuffer;
   exports.StringSink = StringSink;
   exports.Symbol = Symbol;
   exports.Type = Type;
   exports.Uri = Uri;
 })(core || (core = {}));