syntax_data: {"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":"(\"rclass\","}]}
source_snippet:     ("rclass", Unstable(sym::arm_target_feature), &[]),
context_before:     ("neon", Unstable(sym::arm_target_feature), &["vfp3"]),
context_after:     ("sha2", Unstable(sym::arm_target_feature), &["neon"]),