message: Small safety improvement.
diff: @@ -484,15 +484,14 @@ export class DocumentConverter {
  templateLiteral)]))));
  } else if (node.type === 'CallExpression') {
  // A Polymer hybrid/legacy factory function element
  - (node.arguments[0] as ObjectExpression)
  - .properties.splice(
  - 0,
  - 0,
  - jsc.property(
  + const arg = node.arguments[0];
  + if (arg && arg.type === 'ObjectExpression') {
  + arg.properties.unshift(jsc.property(
  'init', jsc.identifier('_template'), templateLiteral));
  }
  }
  }
  + }
  /**
  * Convert dependencies first, so we know what exports they have.
  