syntax_data: {"ast_node_type":"function","tokens":[{"end":60,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn desugaring_kind(self) -> Option<DesugaringKind> {
context_before:     /// if this span is not from a desugaring.
context_after:         match self.ctxt().outer_expn_data().kind {