syntax_data: {"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"negative_impl_span:"}]}
source_snippet:         negative_impl_span: tcx.span_of_impl(negative_impl_def_id),
context_before:         self_ty: overlap.self_ty,
context_after:         positive_impl_span: tcx.span_of_impl(positive_impl_def_id),