syntax_data: {"ast_node_type":"other","tokens":[{"end":45,"kind":"keyword","start":0,"text":"Stability::Stable"}]}
source_snippet:             Stability::Stable { .. } => None,
context_before:             Stability::Unstable(nightly_feature) => Some(nightly_feature),
context_after:             Stability::Forbidden { .. } => panic!("forbidden features should not reach this far"),