Use let chains instead of let else

Author: fee1-dead

compiler/rustc_passes/src/check_const.rs

@@ -198,8 +198,8 @@ impl<'tcx> Visitor<'tcx> for CheckConstVisitor<'tcx> {
             of_trait: Some(trait_ref),
             ..
         }) = item.kind
+            && let Some(def_id) = trait_ref.trait_def_id()
         {
-            let Some(def_id) = trait_ref.trait_def_id() else { return; };
             let source_map = tcx.sess.source_map();
             if !tcx.has_attr(def_id, sym::const_trait) {
                 tcx.sess