syntax_data: {"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"(\"sm_20\","}]}
source_snippet:     ("sm_20", Unstable(sym::nvptx_target_feature), &[]),
context_before:     // tidy-alphabetical-start
context_after:     ("sm_21", Unstable(sym::nvptx_target_feature), &["sm_20"]),