syntax_data: {"ast_node_type":"variable","tokens":[{"end":57,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let pat = (*self).clone().try_fold_with(folder)?;
context_before:     ) -> Result<Self, F::Error> {
context_after:         Ok(if pat == *self { self } else { folder.cx().mk_pat(pat) })