syntax_data: {"ast_node_type":"other","tokens":[{"end":53,"kind":"keyword","start":0,"text":"+"}]}
source_snippet:     + UpcastFrom<I, ty::Binder<I, ty::ClauseKind<I>>>
context_before:     + UpcastFrom<I, ty::ClauseKind<I>>
context_after:     + UpcastFrom<I, I::Clause>