Type check binary expressions

lib/runtime/dart/core.js

 var core = dart.defineLibrary(core, {});
 var _js_helper = dart.lazyImport(_js_helper);
 var _internal = dart.lazyImport(_internal);
 var collection = dart.lazyImport(collection);
 var _interceptors = dart.lazyImport(_interceptors);
 var math = dart.lazyImport(math);
 var convert = dart.lazyImport(convert);
 (function(exports, _js_helper, _internal, collection, _interceptors, math, convert) {
   'use strict';
   class Object {
@@ skipping 1055 matching lines @@
       if (this.message != null && "" != this.message) {
         report = `${report}: ${this.message}`;
       }
       let offset = this.offset;
       if (!(typeof this.source == 'string')) {
         if (offset != -1) {
           report = dart.notNull(report) + ` (at offset ${offset})`;
         }
         return report;
       }
-      if (offset != -1 && (dart.notNull(offset) < 0 || offset['>'](dart.dload(this.source, 'length')))) {
+      if (offset != -1 && (dart.notNull(offset) < 0 || dart.notNull(offset) > dart.notNull(dart.as(dart.dload(this.source, 'length'), num)))) {
         offset = -1;
       }
       if (offset == -1) {
         let source = dart.as(this.source, String);
         if (dart.notNull(source.length) > 78) {
           source = dart.notNull(source.substring(0, 75)) + "...";
         }
         return `${report}\n${source}`;
       }
       let lineNum = 1;
@@ skipping 12 matching lines @@
           lineStart = dart.notNull(i) + 1;
           lastWasCR = true;
         }
       }
       if (dart.notNull(lineNum) > 1) {
         report = dart.notNull(report) + ` (at line ${lineNum}, character ${dart.notNull(offset) - dart.notNull(lineStart) + 1})\n`;
       } else {
         report = dart.notNull(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 = dart.notNull(i) + 1) {
+      for (let i = offset; dart.notNull(i) < dart.notNull(dart.as(dart.dload(this.source, 'length'), num)); i = dart.notNull(i) + 1) {
         let char = dart.as(dart.dsend(this.source, 'codeUnitAt', i), int);
         if (char == 10 || char == 13) {
           lineEnd = i;
           break;
         }
       }
       let length = dart.notNull(lineEnd) - dart.notNull(lineStart);
       let start = lineStart;
       let end = lineEnd;
       let prefix = "";
@@ skipping 2704 matching lines @@
   exports.Stopwatch = Stopwatch;
   exports.String = String;
   exports.RuneIterator = RuneIterator;
   exports.StringBuffer = StringBuffer;
   exports.StringSink = StringSink;
   exports.Symbol = Symbol;
   exports.Type = Type;
   exports.Uri = Uri;
   exports.SupportJsExtensionMethods = SupportJsExtensionMethods;
 })(core, _js_helper, _internal, collection, _interceptors, math, convert);