Add additional hints to the analyzer to catch the 'x is double' dart2js bug.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/Dart2JSVerifier.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/Dart2JSVerifier.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/Dart2JSVerifier.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/Dart2JSVerifier.java
new file mode 100644
index 0000000000000000000000000000000000000000..8fe72c38447f8ecb9d92fb04febde56921d0de4a
--- /dev/null
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/Dart2JSVerifier.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2013, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.dart.engine.internal.hint;
+
+import com.google.dart.engine.ast.IsExpression;
+import com.google.dart.engine.ast.TypeName;
+import com.google.dart.engine.ast.visitor.RecursiveASTVisitor;
+import com.google.dart.engine.element.Element;
+import com.google.dart.engine.element.LibraryElement;
+import com.google.dart.engine.error.HintCode;
+import com.google.dart.engine.internal.error.ErrorReporter;
+import com.google.dart.engine.type.Type;
+
+/**
+ * Instances of the class {@code Dart2JSVerifier} traverse an AST structure looking for hints for
+ * code that will be compiled to JS, such as {@link HintCode#IS_DOUBLE}.
+ * 
+ * @coverage dart.engine.resolver
+ */
+public class Dart2JSVerifier extends RecursiveASTVisitor<Void> {
+
+  /**
+   * The error reporter by which errors will be reported.
+   */
+  private ErrorReporter errorReporter;
+
+  /**
+   * The name of the {@code double} type.
+   */
+  private static final String DOUBLE_TYPE_NAME = "double";
+
+  /**
+   * The name of the {@code int} type.
+   */
+  private static final String INT_TYPE_NAME = "int";
+
+  /**
+   * Create a new instance of the {@link Dart2JSVerifier}.
+   * 
+   * @param errorReporter the error reporter
+   */
+  public Dart2JSVerifier(ErrorReporter errorReporter) {
+    this.errorReporter = errorReporter;
+  }
+
+  @Override
+  public Void visitIsExpression(IsExpression node) {
+    checkForIsDoubleHints(node);
+    return super.visitIsExpression(node);
+  }
+
+  /**
+   * Check for instances of {@code x is double}, {@code x is int}, {@code x is! double} and
+   * {@code x is! int}.
+   * 
+   * @param node the is expression to check
+   * @return {@code true} if and only if a hint code is generated on the passed node
+   * @see HintCode#IS_DOUBLE
+   * @see HintCode#IS_INT
+   * @see HintCode#IS_NOT_DOUBLE
+   * @see HintCode#IS_NOT_INT
+   */
+  private boolean checkForIsDoubleHints(IsExpression node) {
+    TypeName typeName = node.getType();
+    Type type = typeName.getType();
+    if (type != null && type.getElement() != null) {
+      Element element = type.getElement();
+      String typeNameStr = element.getName();
+      LibraryElement libraryElement = element.getLibrary();
+      if (typeNameStr.equals(INT_TYPE_NAME) && libraryElement != null
+          && libraryElement.isDartCore()) {
+        if (node.getNotOperator() == null) {
+          errorReporter.reportError(HintCode.IS_INT, node);
+        } else {
+          errorReporter.reportError(HintCode.IS_NOT_INT, node);
+        }
+        return true;
+      } else if (typeNameStr.equals(DOUBLE_TYPE_NAME) && libraryElement != null
+          && libraryElement.isDartCore()) {
+        if (node.getNotOperator() == null) {
+          errorReporter.reportError(HintCode.IS_DOUBLE, node);
+        } else {
+          errorReporter.reportError(HintCode.IS_NOT_DOUBLE, node);
+        }
+        return true;
+      }
+    }
+    return false;
+  }
+
+}