remove 'delay_span_bug' following 'references_error'

Author: chenyukang

compiler/rustc_const_eval/src/transform/promote_consts.rs

@@ -45,11 +45,10 @@ impl<'tcx> MirPass<'tcx> for PromoteTemps<'tcx> {
         // There's not really any point in promoting errorful MIR.
         //
         // This does not include MIR that failed const-checking, which we still try to promote.
-        if body.return_ty().references_error() {
-            tcx.sess.delay_span_bug(body.span, "PromoteTemps: MIR had errors");
+        if let Err(_) = body.return_ty().error_reported() {
+            debug!("PromoteTemps: MIR had errors");
             return;
         }
-
         if body.source.promoted.is_some() {
             return;
         }