syntax_data: {"ast_node_type":"function","tokens":[{"end":86,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn visit_opaque_ty(&mut self, opaque: &'tcx hir::OpaqueTy<'tcx>) -> Self::Result {
context_before: impl<'tcx> Visitor<'tcx> for RPITVisitor<'_, 'tcx> {
context_after:         self.synthetics.push(associated_type_for_impl_trait_in_trait(