diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc
index b79508143..bef4a26fb 100644
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@@ -48,17 +48,17 @@ static std::tuple<fetchers::Tree, FlakeRef, FlakeRef> fetchOrSubstituteTree(
                 resolvedRef = originalRef.resolve(state.store);
                 auto fetchedResolved = lookupInFlakeCache(flakeCache, originalRef);
                 if (!fetchedResolved) fetchedResolved.emplace(resolvedRef.fetchTree(state.store));
-                flakeCache.push_back({resolvedRef, fetchedResolved.value()});
-                fetched.emplace(fetchedResolved.value());
+                flakeCache.push_back({resolvedRef, *fetchedResolved});
+                fetched.emplace(*fetchedResolved);
             }
             else {
                 throw Error("'%s' is an indirect flake reference, but registry lookups are not allowed", originalRef);
             }
         }
-        flakeCache.push_back({originalRef, fetched.value()});
+        flakeCache.push_back({originalRef, *fetched});
     }
 
-    auto [tree, lockedRef] = fetched.value();
+    auto [tree, lockedRef] = *fetched;
 
     debug("got tree '%s' from '%s'",
         state.store->printStorePath(tree.storePath), lockedRef);
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index 3c1f87f7e..f41242e17 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -192,7 +192,7 @@ public:
     {
         expectArgs({
             .label = label,
-            .optional = true,
+            .optional = optional,
             .handler = {dest}
         });
     }
diff --git a/src/nix/hash.cc b/src/nix/hash.cc
index 0eca4f8ea..494f00a20 100644
--- a/src/nix/hash.cc
+++ b/src/nix/hash.cc
@@ -44,6 +44,7 @@ struct CmdHash : Command
         switch (mode) {
         case FileIngestionMethod::Flat:
             d = "print cryptographic hash of a regular file";
+            break;
         case FileIngestionMethod::Recursive:
             d = "print cryptographic hash of the NAR serialisation of a path";
         };