syntax_data: {"ast_node_type":"other","tokens":[{"end":68,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// constrain `?1` to `u32`. When using the cache entry from the
context_before:     /// Without a cache, the second `Vec<?0> sub Vec<?1>` would eagerly
context_after:     /// first time we've related these types, this only happens when