syntax_data: {"ast_node_type":"variable","tokens":[{"end":69,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let fn_args = if self.tcx().features().return_type_notation()
context_before:     ) -> Result<(), PrintError> {
context_after:             && let Some(ty::ImplTraitInTraitData::Trait { fn_def_id, .. }) =