diff --git a/src/hydra-queue-runner/build-remote.cc b/src/hydra-queue-runner/build-remote.cc
index 5228a63ca..b0b54ac58 100644
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@@ -107,7 +107,7 @@ static void openConnection(Machine::ptr machine, Path tmpDir, int stderrFD, Chil
 
 static void copyClosureTo(std::timed_mutex & sendMutex, Store & destStore,
     serve_proto::BasicConnection & conn, const StorePathSet & paths,
-    bool useSubstitutes = false)
+    SubstituteFlag useSubstitutes = NoSubstitute)
 {
     StorePathSet closure;
     destStore.computeFSClosure(paths, closure);
@@ -310,7 +310,7 @@ void State::buildRemote(ref<Store> destStore,
                 destStore->computeFSClosure(inputs, closure);
                 copyPaths(*destStore, *localStore, closure, NoRepair, NoCheckSigs, NoSubstitute);
             } else {
-                copyClosureTo(machine->state->sendLock, *destStore, conn, inputs, true);
+                copyClosureTo(machine->state->sendLock, *destStore, conn, inputs, Substitute);
             }
 
             auto now2 = std::chrono::steady_clock::now();