message: fix(compiler): correct return in getOptional
diff: @@ -72,10 +72,9 @@ export default class VisitorState<State extends UnknownObject>
  public getOptional(find?: FindState<State>): undefined | State {
  const index = this.getIndex(find);
  if (index === -1) {
  - throw new Error("VisitorState: Could not find stack");
  - } else {
  - return this.stack[index][0];
  + return undefined;
  }
  + return this.stack[index][0];
  }
  public get(find?: FindState<State>): State {
  