syntax_data: {"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // --- It may be reasonable to share this part between expansions with the same definition,
context_before:     // --- The part specific to the macro/desugaring definition.
context_after:     // --- but such sharing is known to bring some minor inconveniences without also bringing