syntax_data: {"ast_node_type":"function","tokens":[{"end":87,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span {
context_before:     /// some other macro (which is the case for built-in and procedural macros).
context_after:         self.with_ctxt(SyntaxContext::root().apply_mark(expn_id, transparency))