syntax_data: {"ast_node_type":"impl","tokens":[{"end":81,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // that impl vars are constrained by the signature, for example).
context_before:                 // well-formed, since we don't do as much HIR analysis (checking
context_after:                 if !tcx.sess.opts.actually_rustdoc {