check for undefined change

Author: pgfearo

src/documentChangeHandler.ts

@@ -35,7 +35,7 @@ export class DocumentChangeHandler {
 						let updateEndPos = new vscode.Position(endTagPos.line, adjustedStartTagPos + activeChange.rangeLength);
 						let updateRange = new vscode.Range(updateStartPos, updateEndPos);
 						this.lastChangePerformed = {range: updateRange, text: activeChange.text};
-						await this.performRename(e.document, this.lastChangePerformed);
+						await this.performRename(e.document, Object.assign(this.lastChangePerformed));
 					} else {
 						this.lastChangePerformed = null;
 					}

src/xslLexerRenameTag.ts

@@ -30,6 +30,9 @@ export class XslLexerRenameTag extends XslLexer {
 
 
     public isStartTagChange(document: vscode.TextDocument, change: vscode.TextDocumentContentChangeEvent) {
+        if (!change) {
+            return -1;
+        }
         let renameRange = change.range;
         let renameChar = renameRange.start.character;
         let text = change.text;