syntax_data: {"ast_node_type":"impl","tokens":[{"end":72,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// certain cases (currently only librustdoc's blanket impl finder),
context_before:     /// since it was usually produced directly from a `DefId`. However,
context_after:     /// a `ParamEnv` may be explicitly constructed with inference types.