syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"(\"sm_21\","}]}
source_snippet:     ("sm_21", Unstable(sym::nvptx_target_feature), &["sm_20"]),
context_before:     ("sm_20", Unstable(sym::nvptx_target_feature), &[]),
context_after:     ("sm_30", Unstable(sym::nvptx_target_feature), &["sm_21"]),