syntax_data: {"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"ImplSource::UserDefined(impl_)"}]}
source_snippet:             ImplSource::UserDefined(impl_) => tcx.dcx().span_delayed_bug(
context_before:         let guar = match impl_source {
context_after:                 tcx.def_span(impl_.impl_def_id),