syntax_data: {"ast_node_type":"function","tokens":[{"end":35,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub const fn root() -> ExpnId {
context_before:     /// Invariant: we do not create any ExpnId with local_id == 0 and krate != 0.
context_after:         ExpnId { krate: LOCAL_CRATE, local_id: ExpnIndex::ZERO }