Issue 1015. Report problem for incompatible right operand and index types.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/ast/IndexExpression.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/ast/IndexExpression.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/ast/IndexExpression.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/ast/IndexExpression.java
index 894a5de645a171f632d5f2696c07fa1c8568f8e9..5692363b8f927946705c02d85dfd5167d427ef12 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/ast/IndexExpression.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/ast/IndexExpression.java
@@ -14,6 +14,7 @@
 package com.google.dart.engine.ast;
 
 import com.google.dart.engine.element.MethodElement;
+import com.google.dart.engine.element.ParameterElement;
 import com.google.dart.engine.scanner.Token;
 import com.google.dart.engine.scanner.TokenType;
 
@@ -309,4 +310,24 @@ public class IndexExpression extends Expression {
     safelyVisitChild(target, visitor);
     safelyVisitChild(index, visitor);
   }
+
+  /**
+   * Return the parameter element representing the parameter to which the value of the index
+   * expression will be bound. May be {@code null}.
+   * <p>
+   * This method is only intended to be used by {@link Expression#getParameterElement()}.
+   * 
+   * @return the parameter element representing the parameter to which the value of the index
+   *         expression will be bound
+   */
+  protected ParameterElement getParameterElementForIndex() {
+    if (element == null) {
+      return null;
+    }
+    ParameterElement[] parameters = element.getParameters();
+    if (parameters.length < 1) {
+      return null;
+    }
+    return parameters[0];
+  }
 }