syntax_data: {"ast_node_type":"other","tokens":[{"end":9,"kind":"keyword","start":0,"text":"where"}]}
source_snippet:     where
context_before:     pub fn span_to_source<F, T>(&self, sp: Span, extract_source: F) -> Result<T, SpanSnippetError>
context_after:         F: Fn(&str, usize, usize) -> Result<T, SpanSnippetError>,