syntax_data: {"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":"(\"fp64\","}]}
source_snippet:     ("fp64", Unstable(sym::mips_target_feature), &[]),
context_before:     // tidy-alphabetical-start
context_after:     ("msa", Unstable(sym::mips_target_feature), &[]),