Issue 13807. Support for type promotion rules.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/LocalVariableElementImpl.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/LocalVariableElementImpl.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/LocalVariableElementImpl.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/LocalVariableElementImpl.java
index cf5688163c67536f01bf20952ff3ef3364e365af..9f4868d80ea2f8607d687a06945aac259b8722f4 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/LocalVariableElementImpl.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/LocalVariableElementImpl.java
@@ -26,6 +26,11 @@ import com.google.dart.engine.utilities.source.SourceRange;
  */
 public class LocalVariableElementImpl extends VariableElementImpl implements LocalVariableElement {
   /**
+   * Is {@code true} if this variable is potentially mutated somewhere in its scope.
+   */
+  private boolean isPotentiallyMutated;
+
+  /**
    * The offset to the beginning of the visible range for this element.
    */
   private int visibleRangeOffset;
@@ -68,6 +73,18 @@ public class LocalVariableElementImpl extends VariableElementImpl implements Loc
     return new SourceRange(visibleRangeOffset, visibleRangeLength);
   }
 
+  @Override
+  public boolean isPotentiallyMutated() {
+    return isPotentiallyMutated;
+  }
+
+  /**
+   * Specifies that this variable is potentially mutated somewhere in its scope.
+   */
+  public void markPotentiallyMutated() {
+    isPotentiallyMutated = true;
+  }
+
   /**
    * Set the visible range for this element to the range starting at the given offset with the given
    * length.