syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"while"}]}
source_snippet:         while self.in_external_macro(sm) {
context_before:     pub fn find_ancestor_not_from_extern_macro(mut self, sm: &SourceMap) -> Option<Span> {
context_after:             self = self.parent_callsite()?;