syntax_data: {"ast_node_type":"other","tokens":[{"end":24,"kind":"keyword","start":0,"text":"err.warn(lint.desc);"}]}
source_snippet:     err.warn(lint.desc);
context_before:     err.is_lint(lint.name_lower(), /* has_future_breakage */ false);
context_after:     err.note(format!("for more information, see {}", future_incompatible.reference));