syntax_data: {"ast_node_type":"function","tokens":[{"end":72,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
context_before: impl<'tcx> std::fmt::Display for UserType<'tcx> {
context_after:         if self.bounds.is_empty() {