syntax_data: {"ast_node_type":"function","tokens":[{"end":99,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn span_look_ahead(&self, span: Span, expect: &str, limit: Option<usize>) -> Option<Span> {
context_before:     /// Check whether span is followed by some specified expected string in limit scope
context_after:         let mut sp = span;