Make int and double nullable by default

test/codegen/expect/dart/_js_helper.js

 var _js_helper;
 (function(exports) {
   'use strict';
   class _Patch extends dart.Object {
     _Patch() {
     }
   }
   let patch = new _Patch();
   class InternalMap extends dart.Object {
   }
@@ skipping 90 matching lines @@
     }
     get isSetter() {
       return this[_kind] === SETTER;
     }
     get isAccessor() {
       return this[_kind] !== METHOD;
     }
     get positionalArguments() {
       if (this.isGetter)
         return /* Unimplemented const */new List.from([]);
-      let argumentCount = this[_arguments].length - this[_namedArgumentNames].length;
+      let argumentCount = dart.notNull(this[_arguments].length) - dart.notNull(this[_namedArgumentNames].length);
       if (argumentCount === 0)
         return /* Unimplemented const */new List.from([]);
       let list = new List.from([]);
-      for (let index = 0; index < argumentCount; index++) {
+      for (let index = 0; dart.notNull(index) < dart.notNull(argumentCount); dart.notNull(index)++) {
         list.add(this[_arguments].get(index));
       }
       return dart.as(makeLiteralListConst(list), core.List);
     }
     get namedArguments() {
       if (this.isAccessor)
         return dart.map();
       let namedArgumentCount = this[_namedArgumentNames].length;
-      let namedArgumentsStartIndex = this[_arguments].length - namedArgumentCount;
+      let namedArgumentsStartIndex = dart.notNull(this[_arguments].length) - dart.notNull(namedArgumentCount);
       if (namedArgumentCount === 0)
         return dart.map();
       let map = new core.Map();
-      for (let i = 0; i < namedArgumentCount; i++) {
-        map.set(new _internal.Symbol.unvalidated(dart.as(this[_namedArgumentNames].get(i), core.String)), this[_arguments].get(namedArgumentsStartIndex + i));
+      for (let i = 0; dart.notNull(i) < dart.notNull(namedArgumentCount); dart.notNull(i)++) {
+        map.set(new _internal.Symbol.unvalidated(dart.as(this[_namedArgumentNames].get(i), core.String)), this[_arguments].get(dart.notNull(namedArgumentsStartIndex) + dart.notNull(i)));
       }
       return map;
     }
     [_getCachedInvocation](object) {
       let interceptor = _interceptors.getInterceptor(object);
       let receiver = object;
       let name = this[_internalName];
       let arguments = this[_arguments];
       let interceptedNames = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.INTERCEPTED_NAMES, core.String));
       let isIntercepted = Object.prototype.hasOwnProperty.call(interceptedNames, name);
@@ skipping 78 matching lines @@
     CachedCatchAllInvocation(name, jsFunction, isIntercepted, cachedInterceptor) {
       this.info = new ReflectionInfo(jsFunction);
       super.CachedInvocation(name, jsFunction, isIntercepted, cachedInterceptor);
     }
     get isGetterStub() {
       return false;
     }
     invokeOn(victim, arguments) {
       let receiver = victim;
       let providedArgumentCount = null;
-      let fullParameterCount = this.info.requiredParameterCount + this.info.optionalParameterCount;
+      let fullParameterCount = dart.notNull(this.info.requiredParameterCount) + dart.notNull(this.info.optionalParameterCount);
       if (!dart.notNull(this.isIntercepted)) {
         if (dart.is(arguments, _interceptors.JSArray)) {
           providedArgumentCount = arguments.length;
-          if (providedArgumentCount < fullParameterCount) {
+          if (dart.notNull(providedArgumentCount) < dart.notNull(fullParameterCount)) {
             arguments = new core.List.from(arguments);
           }
         } else {
           arguments = new core.List.from(arguments);
           providedArgumentCount = arguments.length;
         }
       } else {
         arguments = new List.from([victim]);
         arguments.addAll(arguments);
         if (this.cachedInterceptor !== null)
           receiver = this.cachedInterceptor;
-        providedArgumentCount = arguments.length - 1;
+        providedArgumentCount = dart.notNull(arguments.length) - 1;
       }
-      if (dart.notNull(this.info.areOptionalParametersNamed) && dart.notNull(providedArgumentCount > this.info.requiredParameterCount)) {
+      if (dart.notNull(this.info.areOptionalParametersNamed) && dart.notNull(providedArgumentCount) > dart.notNull(this.info.requiredParameterCount)) {
         throw new UnimplementedNoSuchMethodError(`Invocation of unstubbed method '${this.info.reflectionName}'` + ` with ${arguments.length} arguments.`);
-      } else if (providedArgumentCount < this.info.requiredParameterCount) {
+      } else if (dart.notNull(providedArgumentCount) < dart.notNull(this.info.requiredParameterCount)) {
         throw new UnimplementedNoSuchMethodError(`Invocation of unstubbed method '${this.info.reflectionName}'` + ` with ${providedArgumentCount} arguments (too few).`);
-      } else if (providedArgumentCount > fullParameterCount) {
+      } else if (dart.notNull(providedArgumentCount) > dart.notNull(fullParameterCount)) {
         throw new UnimplementedNoSuchMethodError(`Invocation of unstubbed method '${this.info.reflectionName}'` + ` with ${providedArgumentCount} arguments (too many).`);
       }
-      for (let i = providedArgumentCount; i < fullParameterCount; i++) {
+      for (let i = providedArgumentCount; dart.notNull(i) < dart.notNull(fullParameterCount); dart.notNull(i)++) {
         arguments.add(getMetadata(this.info.defaultValue(i)));
       }
       return this.jsFunction.apply(receiver, arguments);
     }
   }
   class CachedNoSuchMethodInvocation extends dart.Object {
     CachedNoSuchMethodInvocation(interceptor) {
       this.interceptor = interceptor;
     }
     get isNoSuchMethod() {
@@ skipping 18 matching lines @@
       this.functionType = functionType;
       this.cachedSortedIndices = null;
     }
     ReflectionInfo(jsFunction) {
       let data = dart.as(jsFunction.$reflectionInfo, core.List);
       if (data === null)
         return null;
       data = _interceptors.JSArray.markFixedList(data);
       let requiredParametersInfo = data[REQUIRED_PARAMETERS_INFO];
       let requiredParameterCount = requiredParametersInfo >> 1;
-      let isAccessor = (requiredParametersInfo & 1) === 1;
+      let isAccessor = (dart.notNull(requiredParametersInfo) & 1) === 1;
       let optionalParametersInfo = data[OPTIONAL_PARAMETERS_INFO];
       let optionalParameterCount = optionalParametersInfo >> 1;
-      let areOptionalParametersNamed = (optionalParametersInfo & 1) === 1;
+      let areOptionalParametersNamed = (dart.notNull(optionalParametersInfo) & 1) === 1;
       let functionType = data[FUNCTION_TYPE_INDEX];
       return new ReflectionInfo.internal(jsFunction, data, isAccessor, requiredParameterCount, optionalParameterCount, areOptionalParametersNamed, functionType);
     }
     parameterName(parameter) {
       let metadataIndex = null;
       if (_foreign_helper.JS_GET_FLAG('MUST_RETAIN_METADATA')) {
         metadataIndex = this.data[2 * parameter + this.optionalParameterCount + FIRST_DEFAULT_ARGUMENT];
       } else {
         metadataIndex = this.data[parameter + this.optionalParameterCount + FIRST_DEFAULT_ARGUMENT];
       }
       let metadata = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.METADATA, core.String));
       return metadata[metadataIndex];
     }
     parameterMetadataAnnotations(parameter) {
       if (!dart.notNull(_foreign_helper.JS_GET_FLAG('MUST_RETAIN_METADATA'))) {
         throw new core.StateError('metadata has not been preserved');
       } else {
         return dart.as(this.data[2 * parameter + this.optionalParameterCount + FIRST_DEFAULT_ARGUMENT + 1], core.List$(core.int));
       }
     }
     defaultValue(parameter) {
-      if (parameter < this.requiredParameterCount)
-        return dart.as(null, core.int);
+      if (dart.notNull(parameter) < dart.notNull(this.requiredParameterCount))
+        return null;
       return this.data[FIRST_DEFAULT_ARGUMENT + parameter - this.requiredParameterCount];
     }
     defaultValueInOrder(parameter) {
-      if (parameter < this.requiredParameterCount)
-        return dart.as(null, core.int);
-      if (dart.notNull(!dart.notNull(this.areOptionalParametersNamed)) || dart.notNull(this.optionalParameterCount === 1)) {
+      if (dart.notNull(parameter) < dart.notNull(this.requiredParameterCount))
+        return null;
+      if (!dart.notNull(this.areOptionalParametersNamed) || this.optionalParameterCount === 1) {
         return this.defaultValue(parameter);
       }
-      let index = this.sortedIndex(parameter - this.requiredParameterCount);
+      let index = this.sortedIndex(dart.notNull(parameter) - dart.notNull(this.requiredParameterCount));
       return this.defaultValue(index);
     }
     parameterNameInOrder(parameter) {
-      if (parameter < this.requiredParameterCount)
+      if (dart.notNull(parameter) < dart.notNull(this.requiredParameterCount))
         return null;
-      if (dart.notNull(!dart.notNull(this.areOptionalParametersNamed)) || dart.notNull(this.optionalParameterCount === 1)) {
+      if (!dart.notNull(this.areOptionalParametersNamed) || this.optionalParameterCount === 1) {
         return this.parameterName(parameter);
       }
-      let index = this.sortedIndex(parameter - this.requiredParameterCount);
+      let index = this.sortedIndex(dart.notNull(parameter) - dart.notNull(this.requiredParameterCount));
       return this.parameterName(index);
     }
     sortedIndex(unsortedIndex) {
       if (this.cachedSortedIndices === null) {
         this.cachedSortedIndices = new core.List(this.optionalParameterCount);
         let positions = dart.map();
-        for (let i = 0; i < this.optionalParameterCount; i++) {
-          let index = this.requiredParameterCount + i;
+        for (let i = 0; dart.notNull(i) < dart.notNull(this.optionalParameterCount); dart.notNull(i)++) {
+          let index = dart.notNull(this.requiredParameterCount) + dart.notNull(i);
           positions.set(this.parameterName(index), index);
         }
         let index = 0;
         ((_) => {
           _.sort();
           return _;
         }).bind(this)(positions.keys.toList()).forEach(((name) => {
-          this.cachedSortedIndices.set(index++, positions.get(name));
+          this.cachedSortedIndices.set(dart.notNull(index)++, positions.get(name));
         }).bind(this));
       }
       return dart.as(this.cachedSortedIndices.get(unsortedIndex), core.int);
     }
     computeFunctionRti(jsConstructor) {
       if (typeof this.functionType == "number") {
         return getMetadata(dart.as(this.functionType, core.int));
       } else if (typeof this.functionType == "function") {
         let fakeInstance = new jsConstructor();
         setRuntimeTypeInfo(fakeInstance, fakeInstance["<>"]);
@@ skipping 42 matching lines @@
       checkString(source);
       let match = /^\s*[+-]?((0x[a-f0-9]+)|(\d+)|([a-z0-9]+))\s*$/i.exec(source);
       let digitsIndex = 1;
       let hexIndex = 2;
       let decimalIndex = 3;
       let nonDecimalHexIndex = 4;
       if (radix === null) {
         radix = 10;
         if (match !== null) {
           if (dart.dindex(match, hexIndex) !== null) {
-            return dart.notNull(parseInt(source, 16));
+            return parseInt(source, 16);
           }
           if (dart.dindex(match, decimalIndex) !== null) {
-            return dart.notNull(parseInt(source, 10));
+            return parseInt(source, 10);
           }
           return handleError(source);
         }
       } else {
         if (!(typeof radix == number))
           throw new core.ArgumentError("Radix is not an integer");
-        if (dart.notNull(radix < 2) || dart.notNull(radix > 36)) {
+        if (dart.notNull(radix) < 2 || dart.notNull(radix) > 36) {
           throw new core.RangeError(`Radix ${radix} not in range 2..36`);
         }
         if (match !== null) {
-          if (dart.notNull(radix === 10) && dart.notNull(dart.dindex(match, decimalIndex) !== null)) {
-            return dart.notNull(parseInt(source, 10));
+          if (radix === 10 && dart.notNull(dart.dindex(match, decimalIndex) !== null)) {
+            return parseInt(source, 10);
           }
-          if (dart.notNull(radix < 10) || dart.notNull(dart.dindex(match, decimalIndex) === null)) {
+          if (dart.notNull(radix) < 10 || dart.notNull(dart.dindex(match, decimalIndex) === null)) {
             let maxCharCode = null;
-            if (radix <= 10) {
-              maxCharCode = 48 + radix - 1;
+            if (dart.notNull(radix) <= 10) {
+              maxCharCode = 48 + dart.notNull(radix) - 1;
             } else {
-              maxCharCode = 97 + radix - 10 - 1;
+              maxCharCode = 97 + dart.notNull(radix) - 10 - 1;
             }
             let digitsPart = dart.as(dart.dindex(match, digitsIndex), core.String);
-            for (let i = 0; i < digitsPart.length; i++) {
-              let characterCode = digitsPart.codeUnitAt(0) | 32;
-              if (digitsPart.codeUnitAt(i) > maxCharCode) {
+            for (let i = 0; dart.notNull(i) < dart.notNull(digitsPart.length); dart.notNull(i)++) {
+              let characterCode = dart.notNull(digitsPart.codeUnitAt(0)) | 32;
+              if (dart.notNull(digitsPart.codeUnitAt(i)) > dart.notNull(maxCharCode)) {
                 return handleError(source);
               }
             }
           }
         }
       }
       if (match === null)
         return handleError(source);
-      return dart.notNull(parseInt(source, radix));
+      return parseInt(source, radix);
     }
     static parseDouble(source, handleError) {
       checkString(source);
       if (handleError === null)
         handleError = dart.as(_throwFormatException, dart.throw_("Unimplemented type (String) → double"));
-      if (!dart.notNull(/^\s*[+-]?(?:Infinity|NaN|(?:\.\d+|\d+(?:\.\d*)?)(?:[eE][+-]?\d+)?)\s*$/.test(source))) {
+      if (!/^\s*[+-]?(?:Infinity|NaN|(?:\.\d+|\d+(?:\.\d*)?)(?:[eE][+-]?\d+)?)\s*$/.test(source)) {
         return handleError(source);
       }
       let result = parseFloat(source);
       if (result.isNaN) {
         let trimmed = source.trim();
-        if (dart.notNull(dart.notNull(dart.equals(trimmed, 'NaN')) || dart.notNull(dart.equals(trimmed, '+NaN'))) || dart.notNull(dart.equals(trimmed, '-NaN'))) {
-          return dart.notNull(result);
+        if (dart.notNull(dart.equals(trimmed, 'NaN')) || dart.notNull(dart.equals(trimmed, '+NaN')) || dart.notNull(dart.equals(trimmed, '-NaN'))) {
+          return result;
         }
         return handleError(source);
       }
-      return dart.notNull(result);
+      return result;
     }
     static formatType(className, typeArguments) {
       return _js_names.unmangleAllIdentifiersIfPreservedAnyways(`${className}${joinArguments(typeArguments, 0)}`);
     }
     static objectTypeName(object) {
       let name = constructorNameFallback(_interceptors.getInterceptor(object));
       if (dart.equals(name, 'Object')) {
         let decompiled = String(object.constructor).match(/^\s*function\s*(\S*)\s*\(/)[1];
         if (typeof decompiled == string)
           if (/^\w+$/.test(decompiled))
             name = dart.as(decompiled, core.String);
       }
-      if (dart.notNull(name.length > 1) && dart.notNull(core.identical(name.codeUnitAt(0), DOLLAR_CHAR_VALUE))) {
+      if (dart.notNull(name.length) > 1 && dart.notNull(core.identical(name.codeUnitAt(0), DOLLAR_CHAR_VALUE))) {
         name = name.substring(1);
       }
       return formatType(name, dart.as(getRuntimeTypeInfo(object), core.List));
     }
     static objectToString(object) {
       let name = objectTypeName(object);
       return `Instance of '${name}'`;
     }
     static dateNow() {
       return Date.now();
     }
     static initTicker() {
       if (timerFrequency !== null)
         return;
       timerFrequency = 1000;
       timerTicks = dateNow;
       if (typeof window == "undefined")
         return;
       let window = window;
       if (window === null)
         return;
       let performance = window.performance;
       if (performance === null)
         return;
       if (typeof performance.now != "function")
         return;
       timerFrequency = 1000000;
-      timerTicks = (() => (1000 * dart.notNull(performance.now())).floor()).bind(this);
+      timerTicks = (() => (1000 * performance.now()).floor()).bind(this);
     }
     static get isD8() {
       return typeof version == "function" && typeof os == "object" && "system" in os;
     }
     static get isJsshell() {
       return typeof version == "function" && typeof system == "function";
     }
     static currentUri() {
       requiresPreamble();
       if (!!self.location) {
         return self.location.href;
       }
       return null;
     }
     static [_fromCharCodeApply](array) {
       let result = "";
       let kMaxApply = 500;
       let end = array.length;
-      for (let i = 0; i < end; i = kMaxApply) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(end); i = kMaxApply) {
         let subarray = null;
-        if (end <= kMaxApply) {
+        if (dart.notNull(end) <= dart.notNull(kMaxApply)) {
           subarray = array;
         } else {
-          subarray = array.slice(i, i + kMaxApply < end ? i + kMaxApply : end);
+          subarray = array.slice(i, dart.notNull(i) + dart.notNull(kMaxApply) < dart.notNull(end) ? dart.notNull(i) + dart.notNull(kMaxApply) : end);
         }
         result = result + String.fromCharCode.apply(null, subarray);
       }
       return result;
     }
     static stringFromCodePoints(codePoints) {
       let a = new List.from([]);
       for (let i of codePoints) {
         if (!(typeof i == number))
           throw new core.ArgumentError(i);
         if (dart.dbinary(i, '<=', 65535)) {
           a.add(dart.as(i, core.int));
         } else if (dart.dbinary(i, '<=', 1114111)) {
-          a.add(dart.notNull(55296['+'](dart.dbinary(dart.dbinary(dart.dbinary(i, '-', 65536), '>>', 10), '&', 1023))));
-          a.add(dart.notNull(56320['+'](dart.dbinary(i, '&', 1023))));
+          a.add(55296['+'](dart.dbinary(dart.dbinary(dart.dbinary(i, '-', 65536), '>>', 10), '&', 1023)));
+          a.add(56320['+'](dart.dbinary(i, '&', 1023)));
         } else {
           throw new core.ArgumentError(i);
         }
       }
       return _fromCharCodeApply(a);
     }
     static stringFromCharCodes(charCodes) {
       for (let i of charCodes) {
         if (!(typeof i == number))
           throw new core.ArgumentError(i);
@@ skipping 50 matching lines @@
       checkInt(seconds);
       checkInt(milliseconds);
       checkBool(isUtc);
       let jsMonth = dart.dbinary(month, '-', 1);
       let value = null;
       if (isUtc) {
         value = Date.UTC(years, jsMonth, day, hours, minutes, seconds, milliseconds);
       } else {
         value = new Date(years, jsMonth, day, hours, minutes, seconds, milliseconds).valueOf();
       }
-      if (core.bool['||'](dart.dbinary(dart.dload(value, 'isNaN'), '||', dart.dbinary(value, '<', -MAX_MILLISECONDS_SINCE_EPOCH)), dart.dbinary(value, '>', MAX_MILLISECONDS_SINCE_EPOCH))) {
+      if (core.bool['||'](dart.dbinary(dart.dload(value, 'isNaN'), '||', dart.dbinary(value, '<', -dart.notNull(MAX_MILLISECONDS_SINCE_EPOCH))), dart.dbinary(value, '>', MAX_MILLISECONDS_SINCE_EPOCH))) {
         return null;
       }
       if (dart.dbinary(dart.dbinary(years, '<=', 0), '||', dart.dbinary(years, '<', 100)))
         return patchUpY2K(value, years, isUtc);
       return value;
     }
     static patchUpY2K(value, years, isUtc) {
       let date = new Date(value);
       if (isUtc) {
         date.setUTCFullYear(years);
@@ skipping 24 matching lines @@
       return dart.dload(receiver, 'isUtc') ? lazyAsJsDate(receiver).getUTCMinutes() + 0 : lazyAsJsDate(receiver).getMinutes() + 0;
     }
     static getSeconds(receiver) {
       return dart.dload(receiver, 'isUtc') ? lazyAsJsDate(receiver).getUTCSeconds() + 0 : lazyAsJsDate(receiver).getSeconds() + 0;
     }
     static getMilliseconds(receiver) {
       return dart.dload(receiver, 'isUtc') ? lazyAsJsDate(receiver).getUTCMilliseconds() + 0 : lazyAsJsDate(receiver).getMilliseconds() + 0;
     }
     static getWeekday(receiver) {
       let weekday = dart.dload(receiver, 'isUtc') ? lazyAsJsDate(receiver).getUTCDay() + 0 : lazyAsJsDate(receiver).getDay() + 0;
-      return (weekday + 6) % 7 + 1;
+      return (dart.notNull(weekday) + 6) % 7 + 1;
     }
     static valueFromDateString(str) {
       if (!(typeof str == string))
         throw new core.ArgumentError(str);
       let value = Date.parse(str);
       if (value.isNaN)
         throw new core.ArgumentError(str);
       return value;
     }
     static getProperty(object, key) {
-      if (dart.notNull(dart.notNull(dart.notNull(object === null) || dart.notNull(typeof object == boolean)) || dart.notNull(dart.is(object, core.num))) || dart.notNull(typeof object == string)) {
+      if (dart.notNull(object === null) || dart.notNull(typeof object == boolean) || dart.notNull(dart.is(object, core.num)) || dart.notNull(typeof object == string)) {
         throw new core.ArgumentError(object);
       }
       return object[key];
     }
     static setProperty(object, key, value) {
-      if (dart.notNull(dart.notNull(dart.notNull(object === null) || dart.notNull(typeof object == boolean)) || dart.notNull(dart.is(object, core.num))) || dart.notNull(typeof object == string)) {
+      if (dart.notNull(object === null) || dart.notNull(typeof object == boolean) || dart.notNull(dart.is(object, core.num)) || dart.notNull(typeof object == string)) {
         throw new core.ArgumentError(object);
       }
       object[key] = value;
     }
     static functionNoSuchMethod(function, positionalArguments, namedArguments) {
       let argumentCount = 0;
       let arguments = new List.from([]);
       let namedArgumentList = new List.from([]);
       if (positionalArguments !== null) {
         argumentCount = positionalArguments.length;
         arguments.addAll(positionalArguments);
       }
       let names = '';
-      if (dart.notNull(namedArguments !== null) && dart.notNull(!dart.notNull(namedArguments.isEmpty))) {
+      if (dart.notNull(namedArguments !== null) && !dart.notNull(namedArguments.isEmpty)) {
         namedArguments.forEach(((name, argument) => {
           names = `${names}$${name}`;
           namedArgumentList.add(name);
           arguments.add(argument);
-          argumentCount++;
+          dart.notNull(argumentCount)++;
         }).bind(this));
       }
       let selectorName = `${_foreign_helper.JS_GET_NAME("CALL_PREFIX")}$${argumentCount}${names}`;
       return dart.dinvoke(function, 'noSuchMethod', createUnmangledInvocationMirror(dart.throw_("Unimplemented SymbolLiteral: #call"), selectorName, JSInvocationMirror.METHOD, arguments, namedArgumentList));
     }
     static applyFunction(function, positionalArguments, namedArguments) {
       return namedArguments === null ? applyFunctionWithPositionalArguments(function, positionalArguments) : applyFunctionWithNamedArguments(function, positionalArguments, namedArguments);
     }
     static applyFunctionWithPositionalArguments(function, positionalArguments) {
       let argumentCount = 0;
@@ skipping 18 matching lines @@
     static applyFunctionWithNamedArguments(function, positionalArguments, namedArguments) {
       if (namedArguments.isEmpty) {
         return applyFunctionWithPositionalArguments(function, positionalArguments);
       }
       let interceptor = _interceptors.getInterceptor(function);
       let jsFunction = interceptor["call*"];
       if (jsFunction === null) {
         return functionNoSuchMethod(function, positionalArguments, namedArguments);
       }
       let info = new ReflectionInfo(jsFunction);
-      if (dart.notNull(info === null) || dart.notNull(!dart.notNull(info.areOptionalParametersNamed))) {
+      if (dart.notNull(info === null) || !dart.notNull(info.areOptionalParametersNamed)) {
         return functionNoSuchMethod(function, positionalArguments, namedArguments);
       }
       if (positionalArguments !== null) {
         positionalArguments = new core.List.from(positionalArguments);
       } else {
         positionalArguments = new List.from([]);
       }
       if (info.requiredParameterCount !== positionalArguments.length) {
         return functionNoSuchMethod(function, positionalArguments, namedArguments);
       }
       let defaultArguments = new core.Map();
-      for (let i = 0; i < info.optionalParameterCount; i++) {
-        let index = i + info.requiredParameterCount;
+      for (let i = 0; dart.notNull(i) < dart.notNull(info.optionalParameterCount); dart.notNull(i)++) {
+        let index = dart.notNull(i) + dart.notNull(info.requiredParameterCount);
         let parameterName = info.parameterNameInOrder(index);
         let value = info.defaultValueInOrder(index);
         let defaultValue = getMetadata(value);
         defaultArguments.set(parameterName, defaultValue);
       }
       let bad = false;
       namedArguments.forEach(((parameter, value) => {
         if (defaultArguments.containsKey(parameter)) {
           defaultArguments.set(parameter, value);
         } else {
@@ skipping 337 matching lines @@
         }
       }
       return error;
     }
     if (ex === null)
       return null;
     if (typeof ex !== "object")
       return ex;
     if ("dartException" in ex) {
       return saveStackTrace(ex.dartException);
-    } else if (!dart.notNull("message" in ex)) {
+    } else if (!("message" in ex)) {
       return ex;
     }
     let message = ex.message;
-    if (dart.notNull("number" in ex) && dart.notNull(typeof ex.number == "number")) {
+    if ("number" in ex && typeof ex.number == "number") {
       let number = ex.number;
-      let ieErrorCode = number & 65535;
-      let ieFacilityNumber = number >> 16 & 8191;
+      let ieErrorCode = dart.notNull(number) & 65535;
+      let ieFacilityNumber = dart.notNull(number) >> 16 & 8191;
       if (ieFacilityNumber === 10) {
         switch (ieErrorCode) {
           case 438:
             return saveStackTrace(new JsNoSuchMethodError(`${message} (Error ${ieErrorCode})`, null));
           case 445:
           case 5007:
             return saveStackTrace(new NullError(`${message} (Error ${ieErrorCode})`, null));
         }
       }
     }
     if (ex instanceof TypeError) {
       let match = null;
       let nsme = TypeErrorDecoder.noSuchMethodPattern;
       let notClosure = TypeErrorDecoder.notClosurePattern;
       let nullCall = TypeErrorDecoder.nullCallPattern;
       let nullLiteralCall = TypeErrorDecoder.nullLiteralCallPattern;
       let undefCall = TypeErrorDecoder.undefinedCallPattern;
       let undefLiteralCall = TypeErrorDecoder.undefinedLiteralCallPattern;
       let nullProperty = TypeErrorDecoder.nullPropertyPattern;
       let nullLiteralProperty = TypeErrorDecoder.nullLiteralPropertyPattern;
       let undefProperty = TypeErrorDecoder.undefinedPropertyPattern;
       let undefLiteralProperty = TypeErrorDecoder.undefinedLiteralPropertyPattern;
       if ((match = dart.dinvoke(nsme, 'matchTypeError', message)) !== null) {
         return saveStackTrace(new JsNoSuchMethodError(dart.as(message, core.String), match));
       } else if ((match = dart.dinvoke(notClosure, 'matchTypeError', message)) !== null) {
         match.method = "call";
         return saveStackTrace(new JsNoSuchMethodError(dart.as(message, core.String), match));
-      } else if (dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull(dart.notNull((match = dart.dinvoke(nullCall, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(nullLiteralCall, 'matchTypeError', message)) !== null)) || dart.notNull((match = dart.dinvoke(undefCall, 'matchTypeError', message)) !== null)) || dart.notNull((match = dart.dinvoke(undefLiteralCall, 'matchTypeError', message)) !== null)) || dart.notNull((match = dart.dinvoke(nullProperty, 'matchTypeError', message)) !== null)) || dart.notNull((match = dart.dinvoke(nullLiteralCall, 'matchTypeError', message)) !== null)) || dart.notNull((match = dart.dinvoke(undefProperty, 'matchTypeError', message)) !== null)) || dart.notNull((match = dart.dinvoke(undefLiteralProperty, 'matchTypeError', message)) !== null)) {
+      } else if (dart.notNull((match = dart.dinvoke(nullCall, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(nullLiteralCall, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(undefCall, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(undefLiteralCall, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(nullProperty, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(nullLiteralCall, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(undefProperty, 'matchTypeError', message)) !== null) || dart.notNull((match = dart.dinvoke(undefLiteralProperty, 'matchTypeError', message)) !== null)) {
         return saveStackTrace(new NullError(dart.as(message, core.String), match));
       }
       return saveStackTrace(new UnknownJsTypeError(dart.as(typeof message == string ? message : '', core.String)));
     }
     if (ex instanceof RangeError) {
       if (dart.notNull(typeof message == string) && dart.notNull(contains(dart.as(message, core.String), 'call stack'))) {
         return new core.StackOverflowError();
       }
       return saveStackTrace(new core.ArgumentError());
     }
@@ skipping 20 matching lines @@
         return this[_trace];
       let trace = null;
       if (typeof this[_exception] === "object") {
         trace = dart.as(this[_exception].stack, core.String);
       }
       return this[_trace] = trace === null ? '' : trace;
     }
   }
   // Function objectHashCode: (dynamic) → int
   function objectHashCode(object) {
-    if (dart.notNull(object === null) || dart.notNull(typeof object != 'object')) {
+    if (dart.notNull(object === null) || typeof object != 'object') {
       return dart.as(dart.dload(object, 'hashCode'), core.int);
     } else {
       return Primitives.objectHashCode(object);
     }
   }
   // Function fillLiteralMap: (dynamic, Map<dynamic, dynamic>) → dynamic
   function fillLiteralMap(keyValuePairs, result) {
     let index = 0;
     let length = getLength(keyValuePairs);
-    while (index < length) {
-      let key = getIndex(keyValuePairs, index++);
-      let value = getIndex(keyValuePairs, index++);
+    while (dart.notNull(index) < dart.notNull(length)) {
+      let key = getIndex(keyValuePairs, dart.notNull(index)++);
+      let value = getIndex(keyValuePairs, dart.notNull(index)++);
       result.set(key, value);
     }
     return result;
   }
   // Function invokeClosure: (Function, dynamic, int, dynamic, dynamic, dynamic, dynamic) → dynamic
   function invokeClosure(closure, isolate, numberOfArguments, arg1, arg2, arg3, arg4) {
     if (numberOfArguments === 0) {
       return _foreign_helper.JS_CALL_IN_ISOLATE(isolate, () => dart.dinvokef(closure));
     } else if (numberOfArguments === 1) {
       return _foreign_helper.JS_CALL_IN_ISOLATE(isolate, () => dart.dinvokef(closure, arg1));
@@ skipping 35 matching lines @@
       let callName = dart.as(function.$callName, core.String);
       function.$reflectionInfo = reflectionInfo;
       let info = new ReflectionInfo(function);
       let functionType = info.functionType;
       let prototype = isStatic ? Object.create(new TearOffClosure().constructor.prototype) : Object.create(new BoundClosure(null, null, null, null).constructor.prototype);
       prototype.$initialize = prototype.constructor;
       let constructor = isStatic ? function() {
         this.$initialize();
       } : isCsp ? function(a, b, c, d) {
         this.$initialize(a, b, c, d);
-      } : new Function("a", "b", "c", "d", "this.$initialize(a,b,c,d);" + functionCounter++);
+      } : new Function("a", "b", "c", "d", "this.$initialize(a,b,c,d);" + dart.notNull(functionCounter)++);
       prototype.constructor = constructor;
       constructor.prototype = prototype;
       let trampoline = function;
       let isIntercepted = false;
       if (!dart.notNull(isStatic)) {
         if (jsArguments.length == 1) {
           isIntercepted = true;
         }
         trampoline = forwardCallTo(receiver, function, isIntercepted);
         trampoline.$reflectionInfo = reflectionInfo;
       } else {
         prototype.$name = propertyName;
       }
       let signatureFunction = null;
       if (typeof functionType == "number") {
         let metadata = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.METADATA, core.String));
         signatureFunction = function(s) {
           return function() {
             return metadata[s];
           };
         }(functionType);
-      } else if (dart.notNull(!dart.notNull(isStatic)) && dart.notNull(typeof functionType == "function")) {
+      } else if (!dart.notNull(isStatic) && typeof functionType == "function") {
         let getReceiver = isIntercepted ? _foreign_helper.RAW_DART_FUNCTION_REF(BoundClosure.receiverOf) : _foreign_helper.RAW_DART_FUNCTION_REF(BoundClosure.selfOf);
         signatureFunction = function(f, r) {
           return function() {
             return f.apply({$receiver: r(this)}, arguments);
           };
         }(functionType, getReceiver);
       } else {
         throw 'Error in reflectionInfo.';
       }
       prototype[_foreign_helper.JS_SIGNATURE_NAME()] = signatureFunction;
       prototype[callName] = trampoline;
-      for (let i = 1; i < functions.length; i++) {
+      for (let i = 1; dart.notNull(i) < dart.notNull(functions.length); dart.notNull(i)++) {
         let stub = functions.get(i);
         let stubCallName = stub.$callName;
         if (stubCallName !== null) {
           prototype[stubCallName] = isStatic ? stub : forwardCallTo(receiver, stub, isIntercepted);
         }
       }
       prototype["call*"] = trampoline;
       return constructor;
     }
     static cspForwardCall(arity, isSuperCall, stubName, function) {
@@ skipping 48 matching lines @@
     static get isCsp() {
       return typeof dart_precompiled == "function";
     }
     static forwardCallTo(receiver, function, isIntercepted) {
       if (isIntercepted)
         return forwardInterceptedCallTo(receiver, function);
       let stubName = dart.as(function.$stubName, core.String);
       let arity = function.length;
       let lookedUpFunction = receiver[stubName];
       let isSuperCall = !dart.notNull(core.identical(function, lookedUpFunction));
-      if (dart.notNull(dart.notNull(isCsp) || dart.notNull(isSuperCall)) || dart.notNull(arity >= 27)) {
+      if (dart.notNull(isCsp) || dart.notNull(isSuperCall) || dart.notNull(arity) >= 27) {
         return cspForwardCall(arity, isSuperCall, stubName, function);
       }
       if (arity === 0) {
-        return new Function('return function(){' + `return this.${BoundClosure.selfFieldName()}.${stubName}();` + `${functionCounter++}` + '}')();
+        return new Function('return function(){' + `return this.${BoundClosure.selfFieldName()}.${stubName}();` + `${dart.notNull(functionCounter)++}` + '}')();
       }
-      dart.assert(dart.notNull(1 <= arity) && dart.notNull(arity < 27));
+      dart.assert(1 <= dart.notNull(arity) && dart.notNull(arity) < 27);
       let arguments = "abcdefghijklmnopqrstuvwxyz".split("").splice(0, arity).join(",");
-      return new Function(`return function(${arguments}){` + `return this.${BoundClosure.selfFieldName()}.${stubName}(${arguments});` + `${functionCounter++}` + '}')();
+      return new Function(`return function(${arguments}){` + `return this.${BoundClosure.selfFieldName()}.${stubName}(${arguments});` + `${dart.notNull(functionCounter)++}` + '}')();
     }
     static cspForwardInterceptedCall(arity, isSuperCall, name, function) {
       let getSelf = _foreign_helper.RAW_DART_FUNCTION_REF(BoundClosure.selfOf);
       let getReceiver = _foreign_helper.RAW_DART_FUNCTION_REF(BoundClosure.receiverOf);
       if (isSuperCall)
         arity = -1;
       switch (arity) {
         case 0:
           throw new RuntimeError('Intercepted function with no arguments.');
         case 1:
@@ skipping 43 matching lines @@
       }
     }
     static forwardInterceptedCallTo(receiver, function) {
       let selfField = BoundClosure.selfFieldName();
       let receiverField = BoundClosure.receiverFieldName();
       let stubName = dart.as(function.$stubName, core.String);
       let arity = function.length;
       let isCsp = typeof dart_precompiled == "function";
       let lookedUpFunction = receiver[stubName];
       let isSuperCall = !dart.notNull(core.identical(function, lookedUpFunction));
-      if (dart.notNull(dart.notNull(isCsp) || dart.notNull(isSuperCall)) || dart.notNull(arity >= 28)) {
+      if (dart.notNull(isCsp) || dart.notNull(isSuperCall) || dart.notNull(arity) >= 28) {
         return cspForwardInterceptedCall(arity, isSuperCall, stubName, function);
       }
       if (arity === 1) {
-        return new Function('return function(){' + `return this.${selfField}.${stubName}(this.${receiverField});` + `${functionCounter++}` + '}')();
+        return new Function('return function(){' + `return this.${selfField}.${stubName}(this.${receiverField});` + `${dart.notNull(functionCounter)++}` + '}')();
       }
-      dart.assert(dart.notNull(1 < arity) && dart.notNull(arity < 28));
-      let arguments = "abcdefghijklmnopqrstuvwxyz".split("").splice(0, arity - 1).join(",");
-      return new Function(`return function(${arguments}){` + `return this.${selfField}.${stubName}(this.${receiverField}, ${arguments});` + `${functionCounter++}` + '}')();
+      dart.assert(1 < dart.notNull(arity) && dart.notNull(arity) < 28);
+      let arguments = "abcdefghijklmnopqrstuvwxyz".split("").splice(0, dart.notNull(arity) - 1).join(",");
+      return new Function(`return function(${arguments}){` + `return this.${selfField}.${stubName}(this.${receiverField}, ${arguments});` + `${dart.notNull(functionCounter)++}` + '}')();
     }
     toString() {
       return "Closure";
     }
   }
   Closure.FUNCTION_INDEX = 0;
   Closure.NAME_INDEX = 1;
   Closure.CALL_NAME_INDEX = 2;
   Closure.REQUIRED_PARAMETER_INDEX = 3;
   Closure.OPTIONAL_PARAMETER_INDEX = 4;
@@ skipping 25 matching lines @@
     }
     get hashCode() {
       let receiverHashCode = null;
       if (this[_receiver] === null) {
         receiverHashCode = Primitives.objectHashCode(this[_self]);
       } else if (!dart.equals(typeof this[_receiver], 'object')) {
         receiverHashCode = dart.as(dart.dload(this[_receiver], 'hashCode'), core.int);
       } else {
         receiverHashCode = Primitives.objectHashCode(this[_receiver]);
       }
-      return receiverHashCode ^ Primitives.objectHashCode(this[_target]);
+      return dart.notNull(receiverHashCode) ^ dart.notNull(Primitives.objectHashCode(this[_target]));
     }
     static selfOf(closure) {
       return closure[_self];
     }
     static targetOf(closure) {
       return closure[_target];
     }
     static receiverOf(closure) {
       return closure[_receiver];
     }
     static nameOf(closure) {
       return closure[_name];
     }
     static selfFieldName() {
       if (selfFieldNameCache === null) {
         selfFieldNameCache = computeFieldNamed('self');
       }
       return selfFieldNameCache;
     }
     static receiverFieldName() {
       if (receiverFieldNameCache === null) {
         receiverFieldNameCache = computeFieldNamed('receiver');
       }
       return receiverFieldNameCache;
     }
     static computeFieldNamed(fieldName) {
       let template = new BoundClosure('self', 'target', 'receiver', 'name');
       let names = _interceptors.JSArray.markFixedList(dart.as(Object.getOwnPropertyNames(template), core.List));
-      for (let i = 0; i < names.length; i++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(names.length); dart.notNull(i)++) {
         let name = names.get(i);
         if (template[name] === fieldName) {
           return name;
         }
       }
     }
   }
   BoundClosure.selfFieldNameCache = null;
   BoundClosure.receiverFieldNameCache = null;
   // Function jsHasOwnProperty: (dynamic, String) → bool
@@ skipping 115 matching lines @@
   // Function propertyTypeCheck: (dynamic, dynamic) → dynamic
   function propertyTypeCheck(value, property) {
     if (value === null)
       return value;
     if (!!value[property])
       return value;
     propertyTypeError(value, property);
   }
   // Function propertyTypeCast: (dynamic, dynamic) → dynamic
   function propertyTypeCast(value, property) {
-    if (dart.notNull(value === null) || dart.notNull(!!value[property]))
+    if (dart.notNull(value === null) || !!value[property])
       return value;
     propertyTypeCastError(value, property);
   }
   // Function interceptedTypeCheck: (dynamic, dynamic) → dynamic
   function interceptedTypeCheck(value, property) {
     if (value === null)
       return value;
-    if (dart.notNull(core.identical(typeof value, 'object')) && dart.notNull(_interceptors.getInterceptor(value)[property])) {
+    if (dart.notNull(core.identical(typeof value, 'object')) && _interceptors.getInterceptor(value)[property]) {
       return value;
     }
     propertyTypeError(value, property);
   }
   // Function interceptedTypeCast: (dynamic, dynamic) → dynamic
   function interceptedTypeCast(value, property) {
-    if (dart.notNull(value === null) || dart.notNull(dart.notNull(typeof value === "object") && dart.notNull(_interceptors.getInterceptor(value)[property]))) {
+    if (dart.notNull(value === null) || typeof value === "object" && _interceptors.getInterceptor(value)[property]) {
       return value;
     }
     propertyTypeCastError(value, property);
   }
   // Function numberOrStringSuperTypeCheck: (dynamic, dynamic) → dynamic
   function numberOrStringSuperTypeCheck(value, property) {
     if (value === null)
       return value;
     if (typeof value == string)
       return value;
@@ skipping 269 matching lines @@
     }
     toRti() {
       let result = {[_foreign_helper.JS_FUNCTION_TYPE_TAG()]: "dynafunc"};
       if (this.isVoid) {
         result[_foreign_helper.JS_FUNCTION_TYPE_VOID_RETURN_TAG()] = true;
       } else {
         if (!dart.is(this.returnType, DynamicRuntimeType)) {
           result[_foreign_helper.JS_FUNCTION_TYPE_RETURN_TYPE_TAG()] = this.returnType.toRti();
         }
       }
-      if (dart.notNull(this.parameterTypes !== null) && dart.notNull(!dart.notNull(this.parameterTypes.isEmpty))) {
+      if (dart.notNull(this.parameterTypes !== null) && !dart.notNull(this.parameterTypes.isEmpty)) {
         result[_foreign_helper.JS_FUNCTION_TYPE_REQUIRED_PARAMETERS_TAG()] = listToRti(this.parameterTypes);
       }
-      if (dart.notNull(this.optionalParameterTypes !== null) && dart.notNull(!dart.notNull(this.optionalParameterTypes.isEmpty))) {
+      if (dart.notNull(this.optionalParameterTypes !== null) && !dart.notNull(this.optionalParameterTypes.isEmpty)) {
         result[_foreign_helper.JS_FUNCTION_TYPE_OPTIONAL_PARAMETERS_TAG()] = listToRti(this.optionalParameterTypes);
       }
       if (this.namedParameters !== null) {
         let namedRti = Object.create(null);
         let keys = _js_names.extractKeys(this.namedParameters);
-        for (let i = 0; i < keys.length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); dart.notNull(i)++) {
           let name = keys.get(i);
           let rti = dart.dinvoke(this.namedParameters[name], 'toRti');
           namedRti[name] = rti;
         }
         result[_foreign_helper.JS_FUNCTION_TYPE_NAMED_PARAMETERS_TAG()] = namedRti;
       }
       return result;
     }
     static listToRti(list) {
       list = list;
       let result = [];
-      for (let i = 0; i['<'](dart.dload(list, 'length')); i++) {
+      for (let i = 0; i['<'](dart.dload(list, 'length')); dart.notNull(i)++) {
         result.push(dart.dinvoke(dart.dindex(list, i), 'toRti'));
       }
       return result;
     }
     toString() {
       let result = '(';
       let needsComma = false;
       if (this.parameterTypes !== null) {
-        for (let i = 0; i < this.parameterTypes.length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(this.parameterTypes.length); dart.notNull(i)++) {
           let type = this.parameterTypes.get(i);
           if (needsComma)
             result = ', ';
           result = `${type}`;
           needsComma = true;
         }
       }
-      if (dart.notNull(this.optionalParameterTypes !== null) && dart.notNull(!dart.notNull(this.optionalParameterTypes.isEmpty))) {
+      if (dart.notNull(this.optionalParameterTypes !== null) && !dart.notNull(this.optionalParameterTypes.isEmpty)) {
         if (needsComma)
           result = ', ';
         needsComma = false;
         result = '[';
-        for (let i = 0; i < this.optionalParameterTypes.length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(this.optionalParameterTypes.length); dart.notNull(i)++) {
           let type = this.optionalParameterTypes.get(i);
           if (needsComma)
             result = ', ';
           result = `${type}`;
           needsComma = true;
         }
         result = ']';
       } else if (this.namedParameters !== null) {
         if (needsComma)
           result = ', ';
         needsComma = false;
         result = '{';
         let keys = _js_names.extractKeys(this.namedParameters);
-        for (let i = 0; i < keys.length; i++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(keys.length); dart.notNull(i)++) {
           let name = keys.get(i);
           if (needsComma)
             result = ', ';
           let rti = dart.dinvoke(this.namedParameters[name], 'toRti');
           result = `${rti} ${name}`;
           needsComma = true;
         }
         result = '}';
       }
       result = `) -> ${this.returnType}`;
@@ skipping 68 matching lines @@
   // Function convertRtiToRuntimeType: (dynamic) → RuntimeType
   function convertRtiToRuntimeType(rti) {
     if (rti === null) {
       return getDynamicRuntimeType();
     } else if (typeof rti == "function") {
       return new RuntimeTypePlain(rti.name);
     } else if (rti.constructor == Array) {
       let list = dart.as(rti, core.List);
       let name = list.get(0).name;
       let arguments = new List.from([]);
-      for (let i = 1; i < list.length; i++) {
+      for (let i = 1; dart.notNull(i) < dart.notNull(list.length); dart.notNull(i)++) {
         arguments.add(convertRtiToRuntimeType(list.get(i)));
       }
       return new RuntimeTypeGeneric(name, dart.as(arguments, core.List$(RuntimeType)), rti);
     } else if ("func" in rti) {
       return new FunctionTypeInfoDecoderRing(rti).toRuntimeType();
     } else {
       throw new RuntimeError("Cannot convert " + `'${JSON.stringify(rti)}' to RuntimeType.`);
     }
   }
   class RuntimeTypePlain extends RuntimeType {
@@ skipping 142 matching lines @@
       super.Error();
     }
     toString() {
       return `Unsupported operation: ${this[_message]}`;
     }
   }
   // Function random64: () → int
   function random64() {
     let int32a = Math.random() * 0x100000000 >>> 0;
     let int32b = Math.random() * 0x100000000 >>> 0;
-    return int32a + int32b * 4294967296;
+    return dart.notNull(int32a) + dart.notNull(int32b) * 4294967296;
   }
   // Function jsonEncodeNative: (String) → String
   function jsonEncodeNative(string) {
     return JSON.stringify(string);
   }
   // Function getIsolateAffinityTag: (String) → String
   function getIsolateAffinityTag(name) {
     let isolateTagGetter = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.GET_ISOLATE_TAG, core.String));
     return isolateTagGetter(name);
   }
@@ skipping 14 matching lines @@
   function loadDeferredLibrary(loadId) {
     let urisMap = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.DEFERRED_LIBRARY_URIS, core.String));
     let uris = dart.as(urisMap[loadId], core.List$(core.String));
     let hashesMap = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.DEFERRED_LIBRARY_HASHES, core.String));
     let hashes = dart.as(hashesMap[loadId], core.List$(core.String));
     if (uris === null)
       return dart.as(new async.Future.value(null), async.Future$(core.Null));
     let indices = dart.as(new core.List.generate(uris.length, (i) => i), core.List$(core.int));
     let isHunkLoaded = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.IS_HUNK_LOADED, core.String));
     let isHunkInitialized = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.IS_HUNK_INITIALIZED, core.String));
-    let indicesToLoad = indices.where((i) => !dart.notNull(isHunkLoaded(hashes.get(i)))).toList();
+    let indicesToLoad = indices.where((i) => !isHunkLoaded(hashes.get(i))).toList();
     return dart.as(async.Future.wait(dart.as(indicesToLoad.map((i) => _loadHunk(uris.get(i))), core.Iterable$(async.Future))).then((_) => {
-      let indicesToInitialize = indices.where((i) => !dart.notNull(isHunkInitialized(hashes.get(i)))).toList();
+      let indicesToInitialize = indices.where((i) => !isHunkInitialized(hashes.get(i))).toList();
       for (let i of indicesToInitialize) {
         let initializer = _foreign_helper.JS_EMBEDDED_GLOBAL('', dart.as(_js_embedded_names.INITIALIZE_LOADED_HUNK, core.String));
         initializer(hashes.get(i));
       }
       let updated = exports._loadedLibraries.add(loadId);
       if (dart.notNull(updated) && dart.notNull(exports.deferredLoadHook !== null)) {
         exports.deferredLoadHook();
       }
     }), async.Future$(core.Null));
   }
   // Function _loadHunk: (String) → Future<Null>
   function _loadHunk(hunkName) {
     let future = exports._loadingLibraries.get(hunkName);
     if (future !== null) {
       return dart.as(future.then((_) => null), async.Future$(core.Null));
     }
     let uri = _isolate_helper.IsolateNatives.thisScript;
     let index = uri.lastIndexOf('/');
-    uri = `${uri.substring(0, index + 1)}${hunkName}`;
+    uri = `${uri.substring(0, dart.notNull(index) + 1)}${hunkName}`;
     if (dart.notNull(Primitives.isJsshell) || dart.notNull(Primitives.isD8)) {
       return exports._loadingLibraries.set(hunkName, new async.Future(() => {
         try {
           new Function(`load("${uri}")`)();
         } catch (error) {
           let stackTrace = dart.stackTrace(error);
           throw new async.DeferredLoadException(`Loading ${uri} failed.`);
         }
 
         return null;
       }));
     } else if (_isolate_helper.isWorker()) {
       return exports._loadingLibraries.set(hunkName, new async.Future(() => {
         let completer = new async.Completer();
         _isolate_helper.enterJsAsync();
         let leavingFuture = dart.as(completer.future.whenComplete(() => {
           _isolate_helper.leaveJsAsync();
         }), async.Future$(core.Null));
         let index = uri.lastIndexOf('/');
-        uri = `${uri.substring(0, index + 1)}${hunkName}`;
+        uri = `${uri.substring(0, dart.notNull(index) + 1)}${hunkName}`;
         let xhr = new XMLHttpRequest();
         xhr.open("GET", uri);
         xhr.addEventListener("load", convertDartClosureToJS((event) => {
           if (xhr.status !== 200) {
             completer.completeError(new async.DeferredLoadException(`Loading ${uri} failed.`));
             return;
           }
           let code = xhr.responseText;
           try {
             new Function(code)();
@@ skipping 125 matching lines @@
       }
       containsKey(key) {
         if (!(typeof key == string))
           return false;
         if (dart.equals('__proto__', key))
           return false;
         return jsHasOwnProperty(this[_jsObject], dart.as(key, core.String));
       }
       get(key) {
         if (!dart.notNull(this.containsKey(key)))
-          return dart.as(null, V);
+          return null;
         return dart.as(this[_fetch](key), V);
       }
       [_fetch](key) {
         return jsPropertyAccess(this[_jsObject], dart.as(key, core.String));
       }
       forEach(f) {
         let keys = this[_keys];
-        for (let i = 0; i['<'](dart.dload(keys, 'length')); i++) {
+        for (let i = 0; i['<'](dart.dload(keys, 'length')); dart.notNull(i)++) {
           let key = dart.dindex(keys, i);
           f(dart.as(key, K), dart.as(this[_fetch](key), V));
         }
       }
       get keys() {
         return new _ConstantMapKeyIterable(this);
       }
       get values() {
         return new _internal.MappedIterable(this[_keys], dart.as(((key) => this[_fetch](key)).bind(this), dart.throw_("Unimplemented type (K) → V")));
       }
@@ skipping 262 matching lines @@
   function initNativeDispatchContinue() {
     exports.dispatchRecordsForInstanceTags = Object.create(null);
     exports.interceptorsForUncacheableTags = Object.create(null);
     initHooks();
     let map = exports.interceptorsByTag;
     let tags = Object.getOwnPropertyNames(map);
     if (typeof window != "undefined") {
       let context = window;
       let fun = function() {
       };
-      for (let i = 0; i['<'](dart.dload(tags, 'length')); i++) {
+      for (let i = 0; i['<'](dart.dload(tags, 'length')); dart.notNull(i)++) {
         let tag = dart.dindex(tags, i);
         let proto = dart.dinvokef(exports.prototypeForTagFunction, tag);
         if (proto !== null) {
           let interceptorClass = map[tag];
           let record = makeDefaultDispatchRecord(tag, interceptorClass, proto);
           if (record !== null) {
             _interceptors.setDispatchProperty(proto, record);
             fun.prototype = proto;
           }
         }
       }
     }
-    for (let i = 0; i['<'](dart.dload(tags, 'length')); i++) {
+    for (let i = 0; i['<'](dart.dload(tags, 'length')); dart.notNull(i)++) {
       let tag = tags[i];
       if (/^[A-Za-z_]/.test(tag)) {
         let interceptorClass = propertyGet(map, tag);
         propertySet(map, dart.as(dart.dbinary(INSTANCE_CACHED_MARK, '+', tag), core.String), interceptorClass);
         propertySet(map, dart.as(dart.dbinary(UNCACHED_MARK, '+', tag), core.String), interceptorClass);
         propertySet(map, dart.as(dart.dbinary(LEAF_MARK, '+', tag), core.String), interceptorClass);
         propertySet(map, dart.as(dart.dbinary(INTERIOR_MARK, '+', tag), core.String), interceptorClass);
         propertySet(map, dart.as(dart.dbinary(DISCRIMINATED_MARK, '+', tag), core.String), interceptorClass);
       }
     }
   }
   // Function initHooks: () → void
   function initHooks() {
     let hooks = _baseHooks();
     let _fallbackConstructorHooksTransformer = _fallbackConstructorHooksTransformerGenerator(_constructorNameFallback);
     hooks = applyHooksTransformer(_fallbackConstructorHooksTransformer, hooks);
     hooks = applyHooksTransformer(_firefoxHooksTransformer, hooks);
     hooks = applyHooksTransformer(_ieHooksTransformer, hooks);
     hooks = applyHooksTransformer(_operaHooksTransformer, hooks);
     hooks = applyHooksTransformer(_safariHooksTransformer, hooks);
     hooks = applyHooksTransformer(_fixDocumentHooksTransformer, hooks);
     hooks = applyHooksTransformer(_dartExperimentalFixupGetTagHooksTransformer, hooks);
     if (typeof dartNativeDispatchHooksTransformer != "undefined") {
       let transformers = dartNativeDispatchHooksTransformer;
       if (typeof transformers == "function") {
         transformers = new List.from([transformers]);
       }
       if (transformers.constructor == Array) {
-        for (let i = 0; i < transformers.length; i++) {
+        for (let i = 0; dart.notNull(i) < transformers.length; dart.notNull(i)++) {
           let transformer = transformers[i];
           if (typeof transformer == "function") {
             hooks = applyHooksTransformer(transformer, hooks);
           }
         }
       }
     }
     let getTag = hooks.getTag;
     let getUnknownTag = hooks.getUnknownTag;
     let prototypeForTag = hooks.prototypeForTag;
@@ skipping 99 matching lines @@
       let match = this.firstMatch(string);
       if (match !== null)
         return match.group(0);
       return null;
     }
     allMatches(string, start) {
       if (start === void 0)
         start = 0;
       checkString(string);
       checkInt(start);
-      if (dart.notNull(start < 0) || dart.notNull(start > string.length)) {
+      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(string.length)) {
         throw new core.RangeError.range(start, 0, string.length);
       }
       return new _AllMatchesIterable(this, string, start);
     }
     [_execGlobal](string, start) {
       let regexp = this[_nativeGlobalVersion];
       regexp.lastIndex = start;
       let match = dart.as(regexp.exec(string), core.List);
       if (match === null)
         return null;
       return new _MatchImplementation(this, dart.as(match, core.List$(core.String)));
     }
     [_execAnchored](string, start) {
       let regexp = this[_nativeAnchoredVersion];
       regexp.lastIndex = start;
       let match = dart.as(regexp.exec(string), core.List);
       if (match === null)
         return null;
-      if (match.get(match.length - 1) !== null)
+      if (match.get(dart.notNull(match.length) - 1) !== null)
         return null;
       match.length = 1;
       return new _MatchImplementation(this, dart.as(match, core.List$(core.String)));
     }
     matchAsPrefix(string, start) {
       if (start === void 0)
         start = 0;
-      if (dart.notNull(start < 0) || dart.notNull(start > string.length)) {
+      if (dart.notNull(start) < 0 || dart.notNull(start) > dart.notNull(string.length)) {
         throw new core.RangeError.range(start, 0, string.length);
       }
       return this[_execAnchored](string, start);
     }
     get isMultiLine() {
       return this[_isMultiLine];
     }
     get isCaseSensitive() {
       return this[_isCaseSensitive];
     }
   }
   let _match = Symbol('_match');
   class _MatchImplementation extends dart.Object {
     _MatchImplementation(pattern, $_match) {
       this.pattern = pattern;
       this[_match] = $_match;
       dart.assert(typeof this[_match].input == string);
       dart.assert(typeof this[_match].index == number);
     }
     get input() {
       return this[_match].input;
     }
     get start() {
       return this[_match].index;
     }
     get end() {
-      return this.start + this[_match].get(0).length;
+      return dart.notNull(this.start) + dart.notNull(this[_match].get(0).length);
     }
     group(index) {
       return this[_match].get(index);
     }
     get(index) {
       return this.group(index);
     }
     get groupCount() {
-      return this[_match].length - 1;
+      return dart.notNull(this[_match].length) - 1;
     }
     groups(groups) {
       let out = dart.as(new List.from([]), core.List$(core.String));
       for (let i of groups) {
         out.add(this.group(i));
       }
       return out;
     }
   }
   let _re = Symbol('_re');
@@ skipping 19 matching lines @@
       this[_string] = $_string;
       this[_nextIndex] = $_nextIndex;
       this[_current] = null;
     }
     get current() {
       return this[_current];
     }
     moveNext() {
       if (this[_string] === null)
         return false;
-      if (this[_nextIndex] <= this[_string].length) {
+      if (dart.notNull(this[_nextIndex]) <= dart.notNull(this[_string].length)) {
         let match = this[_regExp]._execGlobal(this[_string], this[_nextIndex]);
         if (match !== null) {
           this[_current] = match;
           let nextIndex = match.end;
           if (match.start === nextIndex) {
-            nextIndex++;
+            dart.notNull(nextIndex)++;
           }
           this[_nextIndex] = nextIndex;
           return true;
         }
       }
       this[_current] = null;
       this[_string] = null;
       return false;
     }
   }
   // Function firstMatchAfter: (JSSyntaxRegExp, String, int) → Match
   function firstMatchAfter(regExp, string, start) {
     return regExp._execGlobal(string, start);
   }
   class StringMatch extends dart.Object {
     StringMatch(start, input, pattern) {
       this.start = start;
       this.input = input;
       this.pattern = pattern;
     }
     get end() {
-      return this.start + this.pattern.length;
+      return dart.notNull(this.start) + dart.notNull(this.pattern.length);
     }
     get(g) {
       return this.group(g);
     }
     get groupCount() {
       return 0;
     }
     group(group_) {
       if (group_ !== 0) {
         throw new core.RangeError.value(group_);
@@ skipping 12 matching lines @@
   function allMatchesInStringUnchecked(needle, haystack, startIndex) {
     let result = new core.List();
     let length = haystack.length;
     let patternLength = needle.length;
     while (true) {
       let position = haystack.indexOf(needle, startIndex);
       if (position === -1) {
         break;
       }
       result.add(new StringMatch(position, haystack, needle));
-      let endIndex = position + patternLength;
+      let endIndex = dart.notNull(position) + dart.notNull(patternLength);
       if (endIndex === length) {
         break;
       } else if (position === endIndex) {
-        ++startIndex;
+        ++dart.notNull(startIndex);
       } else {
         startIndex = endIndex;
       }
     }
     return result;
   }
   // Function stringContainsUnchecked: (dynamic, dynamic, dynamic) → dynamic
   function stringContainsUnchecked(receiver, other, startIndex) {
     if (typeof other == string) {
       return !dart.equals(dart.dinvoke(receiver, 'indexOf', other, startIndex), -1);
@@ skipping 23 matching lines @@
   function stringReplaceAllUnchecked(receiver, from, to) {
     checkString(to);
     if (typeof from == string) {
       if (dart.equals(from, "")) {
         if (dart.equals(receiver, "")) {
           return to;
         } else {
           let result = new core.StringBuffer();
           let length = dart.as(dart.dload(receiver, 'length'), core.int);
           result.write(to);
-          for (let i = 0; i < length; i++) {
+          for (let i = 0; dart.notNull(i) < dart.notNull(length); dart.notNull(i)++) {
             result.write(dart.dindex(receiver, i));
             result.write(to);
           }
           return result.toString();
         }
       } else {
         let quoter = new RegExp(ESCAPE_REGEXP, 'g');
         let quoted = from.replace(quoter, "\\$&");
         let replacer = new RegExp(quoted, 'g');
         return stringReplaceJS(receiver, replacer, to);
@@ skipping 35 matching lines @@
     }
     buffer.write(dart.dinvokef(onNonMatch, dart.dinvoke(receiver, 'substring', startIndex)));
     return buffer.toString();
   }
   // Function stringReplaceAllEmptyFuncUnchecked: (dynamic, dynamic, dynamic) → dynamic
   function stringReplaceAllEmptyFuncUnchecked(receiver, onMatch, onNonMatch) {
     let buffer = new core.StringBuffer();
     let length = dart.as(dart.dload(receiver, 'length'), core.int);
     let i = 0;
     buffer.write(dart.dinvokef(onNonMatch, ""));
-    while (i < length) {
+    while (dart.notNull(i) < dart.notNull(length)) {
       buffer.write(dart.dinvokef(onMatch, new StringMatch(i, dart.as(receiver, core.String), "")));
       let code = dart.as(dart.dinvoke(receiver, 'codeUnitAt', i), core.int);
-      if (dart.notNull((code & ~1023) === 55296) && dart.notNull(length > i + 1)) {
-        code = dart.as(dart.dinvoke(receiver, 'codeUnitAt', i + 1), core.int);
-        if ((code & ~1023) === 56320) {
-          buffer.write(dart.dinvokef(onNonMatch, dart.dinvoke(receiver, 'substring', i, i + 2)));
+      if ((dart.notNull(code) & ~1023) === 55296 && dart.notNull(length) > dart.notNull(i) + 1) {
+        code = dart.as(dart.dinvoke(receiver, 'codeUnitAt', dart.notNull(i) + 1), core.int);
+        if ((dart.notNull(code) & ~1023) === 56320) {
+          buffer.write(dart.dinvokef(onNonMatch, dart.dinvoke(receiver, 'substring', i, dart.notNull(i) + 2)));
           i = 2;
           continue;
         }
       }
       buffer.write(dart.dinvokef(onNonMatch, dart.dindex(receiver, i)));
-      i++;
+      dart.notNull(i)++;
     }
     buffer.write(dart.dinvokef(onMatch, new StringMatch(i, dart.as(receiver, core.String), "")));
     buffer.write(dart.dinvokef(onNonMatch, ""));
     return buffer.toString();
   }
   // Function stringReplaceAllStringFuncUnchecked: (dynamic, dynamic, dynamic, dynamic) → dynamic
   function stringReplaceAllStringFuncUnchecked(receiver, pattern, onMatch, onNonMatch) {
     let patternLength = dart.as(dart.dload(pattern, 'length'), core.int);
     if (patternLength === 0) {
       return stringReplaceAllEmptyFuncUnchecked(receiver, onMatch, onNonMatch);
     }
     let length = dart.as(dart.dload(receiver, 'length'), core.int);
     let buffer = new core.StringBuffer();
     let startIndex = 0;
-    while (startIndex < length) {
+    while (dart.notNull(startIndex) < dart.notNull(length)) {
       let position = dart.as(dart.dinvoke(receiver, 'indexOf', pattern, startIndex), core.int);
       if (position === -1) {
         break;
       }
       buffer.write(dart.dinvokef(onNonMatch, dart.dinvoke(receiver, 'substring', startIndex, position)));
       buffer.write(dart.dinvokef(onMatch, new StringMatch(position, dart.as(receiver, core.String), dart.as(pattern, core.String))));
-      startIndex = position + patternLength;
+      startIndex = dart.notNull(position) + dart.notNull(patternLength);
     }
     buffer.write(dart.dinvokef(onNonMatch, dart.dinvoke(receiver, 'substring', startIndex)));
     return buffer.toString();
   }
   // Function stringReplaceFirstUnchecked: (dynamic, dynamic, dynamic, [int]) → dynamic
   function stringReplaceFirstUnchecked(receiver, from, to, startIndex) {
     if (startIndex === void 0)
       startIndex = 0;
     if (typeof from == string) {
       let index = dart.dinvoke(receiver, 'indexOf', from, startIndex);
@@ skipping 113 matching lines @@
   }
   // Function joinArguments: (dynamic, int, {onTypeVariable: (int) → String}) → String
   function joinArguments(types, startIndex, opt$) {
     let onTypeVariable = opt$.onTypeVariable === void 0 ? null : opt$.onTypeVariable;
     if (types === null)
       return '';
     dart.assert(isJsArray(types));
     let firstArgument = true;
     let allDynamic = true;
     let buffer = new core.StringBuffer();
-    for (let index = startIndex; index < getLength(types); index++) {
+    for (let index = startIndex; dart.notNull(index) < dart.notNull(getLength(types)); dart.notNull(index)++) {
       if (firstArgument) {
         firstArgument = false;
       } else {
         buffer.write(', ');
       }
       let argument = getIndex(types, index);
       if (argument !== null) {
         allDynamic = false;
       }
       buffer.write(runtimeTypeToString(argument, {onTypeVariable: onTypeVariable}));
@@ skipping 39 matching lines @@
     let substitution = getField(interceptor, asField);
     return checkArguments(substitution, arguments, checks);
   }
   // Function computeTypeName: (String, List<dynamic>) → String
   function computeTypeName(isField, arguments) {
     let prefixLength = _foreign_helper.JS_OPERATOR_IS_PREFIX().length;
     return Primitives.formatType(isField.substring(prefixLength, isField.length), arguments);
   }
   // Function subtypeCast: (Object, String, List<dynamic>, String) → Object
   function subtypeCast(object, isField, checks, asField) {
-    if (dart.notNull(object !== null) && dart.notNull(!dart.notNull(checkSubtype(object, isField, checks, asField)))) {
+    if (dart.notNull(object !== null) && !dart.notNull(checkSubtype(object, isField, checks, asField))) {
       let actualType = Primitives.objectTypeName(object);
       let typeName = computeTypeName(isField, checks);
       throw new CastErrorImplementation(actualType, typeName);
     }
     return object;
   }
   // Function assertSubtype: (Object, String, List<dynamic>, String) → Object
   function assertSubtype(object, isField, checks, asField) {
-    if (dart.notNull(object !== null) && dart.notNull(!dart.notNull(checkSubtype(object, isField, checks, asField)))) {
+    if (dart.notNull(object !== null) && !dart.notNull(checkSubtype(object, isField, checks, asField))) {
       let typeName = computeTypeName(isField, checks);
       throw new TypeErrorImplementation(object, typeName);
     }
     return object;
   }
   // Function assertIsSubtype: (dynamic, dynamic, String) → dynamic
   function assertIsSubtype(subtype, supertype, message) {
     if (!dart.notNull(isSubtype(subtype, supertype))) {
       throwTypeError(message);
     }
   }
   // Function throwTypeError: (dynamic) → dynamic
   function throwTypeError(message) {
     throw new TypeErrorImplementation.fromMessage(dart.as(message, core.String));
   }
   // Function checkArguments: (dynamic, dynamic, dynamic) → bool
   function checkArguments(substitution, arguments, checks) {
     return areSubtypes(substitute(substitution, arguments), checks);
   }
   // Function areSubtypes: (dynamic, dynamic) → bool
   function areSubtypes(s, t) {
     if (dart.notNull(s === null) || dart.notNull(t === null))
       return true;
     dart.assert(isJsArray(s));
     dart.assert(isJsArray(t));
     dart.assert(getLength(s) === getLength(t));
     let len = getLength(s);
-    for (let i = 0; i < len; i++) {
+    for (let i = 0; dart.notNull(i) < dart.notNull(len); dart.notNull(i)++) {
       if (!dart.notNull(isSubtype(getIndex(s, i), getIndex(t, i)))) {
         return false;
       }
     }
     return true;
   }
   // Function computeSignature: (dynamic, dynamic, dynamic) → dynamic
   function computeSignature(signature, context, contextName) {
     let typeArguments = getRuntimeTypeArguments(context, contextName);
     return invokeOn(signature, context, typeArguments);
   }
   // Function isSupertypeOfNull: (dynamic) → bool
   function isSupertypeOfNull(type) {
-    return dart.notNull(dart.notNull(type === null) || dart.notNull(dart.equals(getConstructorName(type), _foreign_helper.JS_OBJECT_CLASS_NAME()))) || dart.notNull(dart.equals(getConstructorName(type), _foreign_helper.JS_NULL_CLASS_NAME()));
+    return dart.notNull(type === null) || dart.notNull(dart.equals(getConstructorName(type), _foreign_helper.JS_OBJECT_CLASS_NAME())) || dart.notNull(dart.equals(getConstructorName(type), _foreign_helper.JS_NULL_CLASS_NAME()));
   }
   // Function checkSubtypeOfRuntimeType: (dynamic, dynamic) → bool
   function checkSubtypeOfRuntimeType(o, t) {
     if (o === null)
       return isSupertypeOfNull(t);
     if (t === null)
       return true;
     let rti = getRuntimeTypeInfo(o);
     o = _interceptors.getInterceptor(o);
     let type = o.constructor;
     if (rti !== null) {
       rti = rti.slice();
       rti.splice(0, 0, type);
       type = rti;
     } else if (hasField(t, `${_foreign_helper.JS_FUNCTION_TYPE_TAG()}`)) {
       let signatureName = `${_foreign_helper.JS_OPERATOR_IS_PREFIX()}_${getField(t, _foreign_helper.JS_FUNCTION_TYPE_TAG())}`;
       if (hasField(o, signatureName))
         return true;
       let targetSignatureFunction = getField(o, `${_foreign_helper.JS_SIGNATURE_NAME()}`);
       if (targetSignatureFunction === null)
         return false;
       type = invokeOn(targetSignatureFunction, o, null);
       return isFunctionSubtype(type, t);
     }
     return isSubtype(type, t);
   }
   // Function subtypeOfRuntimeTypeCast: (Object, dynamic) → Object
   function subtypeOfRuntimeTypeCast(object, type) {
-    if (dart.notNull(object !== null) && dart.notNull(!dart.notNull(checkSubtypeOfRuntimeType(object, type)))) {
+    if (dart.notNull(object !== null) && !dart.notNull(checkSubtypeOfRuntimeType(object, type))) {
       let actualType = Primitives.objectTypeName(object);
       throw new CastErrorImplementation(actualType, runtimeTypeToString(type));
     }
     return object;
   }
   // Function assertSubtypeOfRuntimeType: (Object, dynamic) → Object
   function assertSubtypeOfRuntimeType(object, type) {
-    if (dart.notNull(object !== null) && dart.notNull(!dart.notNull(checkSubtypeOfRuntimeType(object, type)))) {
+    if (dart.notNull(object !== null) && !dart.notNull(checkSubtypeOfRuntimeType(object, type))) {
       throw new TypeErrorImplementation(object, runtimeTypeToString(type));
     }
     return object;
   }
   // Function getArguments: (dynamic) → dynamic
   function getArguments(type) {
     return isJsArray(type) ? type.slice(1) : null;
   }
   // Function isSubtype: (dynamic, dynamic) → bool
   function isSubtype(s, t) {
@@ skipping 12 matching lines @@
     let name = runtimeTypeToString(typeOfT);
     let substitution = null;
     if (isNotIdentical(typeOfT, typeOfS)) {
       let test = `${_foreign_helper.JS_OPERATOR_IS_PREFIX()}${name}`;
       let typeOfSPrototype = typeOfS.prototype;
       if (hasNoField(typeOfSPrototype, test))
         return false;
       let field = `${_foreign_helper.JS_OPERATOR_AS_PREFIX()}${runtimeTypeToString(typeOfT)}`;
       substitution = getField(typeOfSPrototype, field);
     }
-    if (dart.notNull(dart.notNull(!dart.notNull(isJsArray(s))) && dart.notNull(substitution === null)) || dart.notNull(!dart.notNull(isJsArray(t)))) {
+    if (!dart.notNull(isJsArray(s)) && dart.notNull(substitution === null) || !dart.notNull(isJsArray(t))) {
       return true;
     }
     return checkArguments(substitution, getArguments(s), getArguments(t));
   }
   // Function isAssignable: (dynamic, dynamic) → bool
   function isAssignable(s, t) {
     return dart.notNull(isSubtype(s, t)) || dart.notNull(isSubtype(t, s));
   }
   // Function areAssignable: (List<dynamic>, List, bool) → bool
   function areAssignable(s, t, allowShorter) {
     if (dart.notNull(t === null) && dart.notNull(s === null))
       return true;
     if (t === null)
       return allowShorter;
     if (s === null)
       return false;
     dart.assert(isJsArray(s));
     dart.assert(isJsArray(t));
     let sLength = getLength(s);
     let tLength = getLength(t);
     if (allowShorter) {
-      if (sLength < tLength)
+      if (dart.notNull(sLength) < dart.notNull(tLength))
         return false;
     } else {
       if (sLength !== tLength)
         return false;
     }
-    for (let i = 0; i < tLength; i++) {
+    for (let i = 0; dart.notNull(i) < dart.notNull(tLength); dart.notNull(i)++) {
       if (!dart.notNull(isAssignable(getIndex(s, i), getIndex(t, i)))) {
         return false;
       }
     }
     return true;
   }
   // Function areAssignableMaps: (dynamic, dynamic) → bool
   function areAssignableMaps(s, t) {
     if (t === null)
       return true;
     if (s === null)
       return false;
     dart.assert(isJsObject(s));
     dart.assert(isJsObject(t));
     let names = _interceptors.JSArray.markFixedList(dart.as(Object.getOwnPropertyNames(t), core.List));
-    for (let i = 0; i < names.length; i++) {
+    for (let i = 0; dart.notNull(i) < dart.notNull(names.length); dart.notNull(i)++) {
       let name = names.get(i);
       if (!Object.hasOwnProperty.call(s, name)) {
         return false;
       }
       let tType = t[name];
       let sType = s[name];
       if (!dart.notNull(isAssignable(tType, sType)))
         return false;
     }
     return true;
@@ skipping 14 matching lines @@
         return false;
     }
     let sParameterTypes = getField(s, `${_foreign_helper.JS_FUNCTION_TYPE_REQUIRED_PARAMETERS_TAG()}`);
     let tParameterTypes = getField(t, `${_foreign_helper.JS_FUNCTION_TYPE_REQUIRED_PARAMETERS_TAG()}`);
     let sOptionalParameterTypes = getField(s, `${_foreign_helper.JS_FUNCTION_TYPE_OPTIONAL_PARAMETERS_TAG()}`);
     let tOptionalParameterTypes = getField(t, `${_foreign_helper.JS_FUNCTION_TYPE_OPTIONAL_PARAMETERS_TAG()}`);
     let sParametersLen = sParameterTypes !== null ? getLength(sParameterTypes) : 0;
     let tParametersLen = tParameterTypes !== null ? getLength(tParameterTypes) : 0;
     let sOptionalParametersLen = sOptionalParameterTypes !== null ? getLength(sOptionalParameterTypes) : 0;
     let tOptionalParametersLen = tOptionalParameterTypes !== null ? getLength(tOptionalParameterTypes) : 0;
-    if (sParametersLen > tParametersLen) {
+    if (dart.notNull(sParametersLen) > dart.notNull(tParametersLen)) {
       return false;
     }
-    if (sParametersLen + sOptionalParametersLen < tParametersLen + tOptionalParametersLen) {
+    if (dart.notNull(sParametersLen) + dart.notNull(sOptionalParametersLen) < dart.notNull(tParametersLen) + dart.notNull(tOptionalParametersLen)) {
       return false;
     }
     if (sParametersLen === tParametersLen) {
       if (!dart.notNull(areAssignable(dart.as(sParameterTypes, core.List), dart.as(tParameterTypes, core.List), false)))
         return false;
       if (!dart.notNull(areAssignable(dart.as(sOptionalParameterTypes, core.List), dart.as(tOptionalParameterTypes, core.List), true))) {
         return false;
       }
     } else {
       let pos = 0;
-      for (; pos < sParametersLen; pos++) {
+      for (; dart.notNull(pos) < dart.notNull(sParametersLen); dart.notNull(pos)++) {
         if (!dart.notNull(isAssignable(getIndex(sParameterTypes, pos), getIndex(tParameterTypes, pos)))) {
           return false;
         }
       }
       let sPos = 0;
       let tPos = pos;
-      for (; tPos < tParametersLen; sPos++, tPos++) {
+      for (; dart.notNull(tPos) < dart.notNull(tParametersLen); dart.notNull(sPos)++, dart.notNull(tPos)++) {
         if (!dart.notNull(isAssignable(getIndex(sOptionalParameterTypes, sPos), getIndex(tParameterTypes, tPos)))) {
           return false;
         }
       }
       tPos = 0;
-      for (; tPos < tOptionalParametersLen; sPos++, tPos++) {
+      for (; dart.notNull(tPos) < dart.notNull(tOptionalParametersLen); dart.notNull(sPos)++, dart.notNull(tPos)++) {
         if (!dart.notNull(isAssignable(getIndex(sOptionalParameterTypes, sPos), getIndex(tOptionalParameterTypes, tPos)))) {
           return false;
         }
       }
     }
     let sNamedParameters = getField(s, `${_foreign_helper.JS_FUNCTION_TYPE_NAMED_PARAMETERS_TAG()}`);
     let tNamedParameters = getField(t, `${_foreign_helper.JS_FUNCTION_TYPE_NAMED_PARAMETERS_TAG()}`);
     return areAssignableMaps(sNamedParameters, tNamedParameters);
   }
   // Function invoke: (dynamic, dynamic) → dynamic
@@ skipping 277 matching lines @@
   exports.getIndex = getIndex;
   exports.getLength = getLength;
   exports.isJsArray = isJsArray;
   exports.hasField = hasField;
   exports.hasNoField = hasNoField;
   exports.isJsFunction = isJsFunction;
   exports.isJsObject = isJsObject;
   exports.isIdentical = isIdentical;
   exports.isNotIdentical = isNotIdentical;
 })(_js_helper || (_js_helper = {}));