syntax_data: {"ast_node_type":"other","tokens":[{"end":58,"kind":"keyword","start":0,"text":"ClauseKind::UnstableFeature(feature_name)"}]}
source_snippet:             ClauseKind::UnstableFeature(feature_name) => {
context_before:             }
context_after:                 write!(f, "UnstableFeature({feature_name:?})")