syntax_data: {"ast_node_type":"function","tokens":[{"end":51,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn as_range(&self) -> Option<&PatRange<'tcx>> {
context_before: impl<'tcx> TestCase<'tcx> {
context_after:         if let Self::Range(v) = self { Some(v.as_ref()) } else { None }