refactor(3p/nix): Apply clang-tidy's performance-* fixes r/789

This applies the performance fixes listed here:

https://clang.llvm.org/extra/clang-tidy/checks/list.html

1 files changed, 3 insertions, 3 deletions

diff --git a/third_party/nix/src/nix-daemon/nix-daemon.cc b/third_party/nix/src/nix-daemon/nix-daemon.cc
index 060cc10497..9f5e8b7cbe 100644
--- a/third_party/nix/src/nix-daemon/nix-daemon.cc
+++ b/third_party/nix/src/nix-daemon/nix-daemon.cc
@@ -194,9 +194,9 @@ struct RetrieveRegularNARSink : ParseSink {
   }
 };
 
-static void performOp(TunnelLogger* logger, ref<Store> store, bool trusted,
-                      unsigned int clientVersion, Source& from, Sink& to,
-                      unsigned int op) {
+static void performOp(TunnelLogger* logger, const ref<Store>& store,
+                      bool trusted, unsigned int clientVersion, Source& from,
+                      Sink& to, unsigned int op) {
   switch (op) {
     case wopIsValidPath: {
       /* 'readStorePath' could raise an error leading to the connection