Prevent the semicolon handler from adding indexes to message options."

This patch works around a bug in the protobuf grammar that causes the
parser to misclassify message options as message fields if they contain
syntax errors or unresolved symbols.

Change-Id: Ieee07fe51e9120f8952be839acf8b2b8803630b8

com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/commands/semicolon/SmartSemicolonHandler.java

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/commands/semicolon/SmartSemicolonHandler.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/commands/semicolon/SmartSemicolonHandler.java
index 005cca6..f250c08 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/commands/semicolon/SmartSemicolonHandler.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/commands/semicolon/SmartSemicolonHandler.java
@@ -149,7 +149,16 @@
           model = model.eContainer();
         }
 
-        if (model instanceof MessageField || model instanceof Group || model instanceof Literal) {
+        if (model instanceof MessageField) {
+          // If a non-indexed MessageElement, such as an Option, contains syntax errors or
+          // unresolved symbols, the Protobuf Parser may mistakenly classify it as a MessageField.
+          // Invalid MessageFields can be filtered out by verifying the presence of the field "name".
+          if (((MessageField) model).getName() != null) {
+            return model;
+          }
+        }
+
+        if (model instanceof Group || model instanceof Literal) {
           return model;
         }
       }