syntax_data: {"ast_node_type":"function","tokens":[{"end":98,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn try_fold_with<F: FallibleTypeFolder<I>>(self, folder: &mut F) -> Result<(T, U), F::Error> {
context_before: impl<I: Interner, T: TypeFoldable<I>, U: TypeFoldable<I>> TypeFoldable<I> for (T, U) {
context_after:         Ok((self.0.try_fold_with(folder)?, self.1.try_fold_with(folder)?))