syntax_data: {"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":"self.new.fmt_diff_with(&self.old,"}]}
source_snippet:         self.new.fmt_diff_with(&self.old, self.ctxt, f)
context_before:     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
context_after:     }