Remove more type casts

pkg/analyzer/lib/src/generated/source.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.generated.source;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 250 matching lines @@
   /**
    * Return the offset of the first character on the line with the given
    * [lineNumber].
    */
   int getOffsetOfLine(int lineNumber) {
     if (lineNumber < 0 || lineNumber >= lineCount) {
       throw new ArgumentError('Invalid line number: $lineNumber');
     }
     return _lineStarts[lineNumber];
   }
-
 }
 
 /**
  * Instances of the class `Location` represent the location of a character as a line and
  * column pair.
  */
 class LineInfo_Location {
   /**
    * The one-based index of the line containing the character.
    */
@@ skipping 467 matching lines @@
   /**
    * @return the 0-based index of the after-last character of the source code for this element,
    *         relative to the source buffer in which this element is contained.
    */
   int get end => offset + length;
 
   @override
   int get hashCode => 31 * offset + length;
 
   @override
-  bool operator ==(Object obj) {
-    if (obj is! SourceRange) {
-      return false;
-    }
-    SourceRange sourceRange = obj as SourceRange;
-    return sourceRange.offset == offset && sourceRange.length == length;
+  bool operator ==(Object other) {
+    return other is SourceRange &&
+        other.offset == offset &&
+        other.length == length;
   }
 
   /**
    * @return `true` if <code>x</code> is in [offset, offset + length) interval.
    */
   bool contains(int x) => offset <= x && x < offset + length;
 
   /**
    * @return `true` if <code>x</code> is in (offset, offset + length) interval.
    */
@@ skipping 143 matching lines @@
   Source resolveAbsolute(Uri uri, [Uri actualUri]);
 
   /**
    * Return an absolute URI that represents the given [source], or `null` if a
    * valid URI cannot be computed.
    *
    * The computation should be based solely on [source.fullName].
    */
   Uri restoreAbsolute(Source source) => null;
 }