syntax_data: {"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                         let const_span = self.tcx.def_span(def_id);
context_before:                     Res::Def(DefKind::ConstParam, def_id) => {
context_after:                         self.tcx.dcx().emit_err(ConstParamInPattern { span, const_span })