syntax_data: {"ast_node_type":"import","tokens":[{"end":67,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // we use compiler options to determine the crate_type.
context_before:             // FIXME: When crate_type is not available,
context_after:             // We can't check `#![crate_type = "proc-macro"]` here.