Made getOccs more resilient.

Author: DanielRosenwasser

src/compiler/parser.ts

@@ -483,6 +483,22 @@ module ts {
         nodeIsNestedInLabel(label: Identifier, requireIterationStatement: boolean, stopAtFunctionBoundary: boolean): ControlBlockContext;
     }
 
+    export function isKeyword(token: SyntaxKind): boolean {
+        return SyntaxKind.FirstKeyword <= token && token <= SyntaxKind.LastKeyword;
+    }
+
+    export function isModifier(token: SyntaxKind): boolean {
+        switch (token) {
+            case SyntaxKind.PublicKeyword:
+            case SyntaxKind.PrivateKeyword:
+            case SyntaxKind.StaticKeyword:
+            case SyntaxKind.ExportKeyword:
+            case SyntaxKind.DeclareKeyword:
+                return true;
+        }
+        return false;
+    }
+
     export function createSourceFile(filename: string, sourceText: string, languageVersion: ScriptTarget, version: string, isOpen: boolean = false): SourceFile {
         var file: SourceFile;
         var scanner: Scanner;
@@ -853,23 +869,6 @@ module ts {
             return parseIdentifierName();
         }
 
-
-        function isKeyword(token: SyntaxKind): boolean {
-            return SyntaxKind.FirstKeyword <= token && token <= SyntaxKind.LastKeyword;
-        }
-
-        function isModifier(token: SyntaxKind): boolean {
-            switch (token) {
-                case SyntaxKind.PublicKeyword:
-                case SyntaxKind.PrivateKeyword:
-                case SyntaxKind.StaticKeyword:
-                case SyntaxKind.ExportKeyword:
-                case SyntaxKind.DeclareKeyword:
-                    return true;
-            }
-            return false;
-        }
-
         function parseContextualModifier(t: SyntaxKind): boolean {
             return token === t && tryParse(() => {
                 nextToken();

src/services/services.ts

@@ -2172,27 +2172,37 @@ module ts {
                 case SyntaxKind.TryKeyword:
                 case SyntaxKind.CatchKeyword:
                 case SyntaxKind.FinallyKeyword:
-                    return getTryCatchFinallyOccurrences(<TryStatement>node.parent.parent);
+                    return getTryCatchFinallyOccurrences(<TryStatement>(node.parent && node.parent.parent));
             }
 
             return undefined;
 
-            function getTryCatchFinallyOccurrences(tryStatement: TryStatement): ReferenceEntry[] {
+            function getTryCatchFinallyOccurrences(tryStatement: TryStatement): ReferenceEntry[]{
+                if (!tryStatement || tryStatement.kind !== SyntaxKind.TryStatement) {
+                    return undefined;
+                }
+
                 var keywords: Node[] = [];
 
-                keywords.push(tryStatement.getFirstToken())
+                pushIfKeyword(keywords, tryStatement.getFirstToken());
 
                 if (tryStatement.catchBlock) {
-                    keywords.push(tryStatement.catchBlock.getFirstToken());
+                    pushIfKeyword(keywords, tryStatement.catchBlock.getFirstToken());
                 }
 
                 if (tryStatement.finallyBlock) {
-                    keywords.push(tryStatement.finallyBlock.getFirstToken());
+                    pushIfKeyword(keywords, tryStatement.finallyBlock.getFirstToken());
                 }
 
                 return keywordsToReferenceEntries(keywords);
             }
 
+            function pushIfKeyword(keywordList: Node[], token: Node) {
+                if (token && isKeyword(token.kind)) {
+                    keywordList.push(token);
+                }
+            }
+
             function keywordsToReferenceEntries(keywords: Node[]): ReferenceEntry[]{
                 return keywords.map(keyword =>
                     new ReferenceEntry(filename, TypeScript.TextSpan.fromBounds(keyword.getStart(), keyword.end), /* isWriteAccess */ false)