syntax_data: {"ast_node_type":"function","tokens":[{"end":56,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn substitute_dummy(self, other: Span) -> Span {
context_before:     /// Returns `self` if `self` is not the dummy span, and `other` otherwise.
context_after:         if self.is_dummy() { other } else { self }