syntax_data: {"ast_node_type":"other","tokens":[{"end":37,"kind":"keyword","start":0,"text":"externs:"}]}
source_snippet:         externs: Externs [UNTRACKED],
context_before:         cg: CodegenOptions [SUBSTRUCT CodegenOptionsTargetModifiers CodegenOptions],
context_after:         crate_name: Option<String> [TRACKED],