syntax_data: {"ast_node_type":"other","tokens":[{"end":53,"kind":"keyword","start":0,"text":"Stability::Unstable(nightly_feature)"}]}
source_snippet:             Stability::Unstable(nightly_feature) => {
context_before:             Stability::Stable => {}
context_after:                 nightly_feature.hash_stable(hcx, hasher);