diff --git a/src/libstore/build/create-derivation-and-realise-goal.cc b/src/libstore/build/create-derivation-and-realise-goal.cc
index b01042f00..60f67956d 100644
--- a/src/libstore/build/create-derivation-and-realise-goal.cc
+++ b/src/libstore/build/create-derivation-and-realise-goal.cc
@@ -96,7 +96,7 @@ void CreateDerivationAndRealiseGoal::getDerivation()
         auto drvPath = StorePath::dummy;
         try {
             drvPath = resolveDerivedPath(worker.store, *drvReq);
-        } catch (MissingRealisation) {
+        } catch (MissingRealisation &) {
             return std::nullopt;
         }
         return worker.evalStore.isValidPath(drvPath) || worker.store.isValidPath(drvPath)
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index f24a6e165..5a10c69e2 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -60,7 +60,7 @@ void initLibUtil() {
     bool caught = false;
     try {
         throwExceptionSelfCheck();
-    } catch (nix::Error _e) {
+    } catch (const nix::Error & _e) {
         caught = true;
     }
     // This is not actually the main point of this check, but let's make sure anyway: