syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"+"}]}
source_snippet:     + UpcastFrom<I, ty::TraitPredicate<I>>
context_before:     + UpcastFrom<I, ty::Binder<I, ty::TraitRef<I>>>
context_after:     + UpcastFrom<I, ty::OutlivesPredicate<I, I::Ty>>