fix(3p/nix): Fix all remaining compiler warnings r/1403

This compiles under `-Wall -Werror`.

The largest chunk of this change is `final` qualifiers for the various
Nix CLI command structs, which inherit from a Command class that has
more virtual functions than are implemented by each command.

Change-Id: I0925e6e1a39013f026773db5816e4a77d50f3b4a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1294
Tested-by: BuildkiteCI
Reviewed-by: isomer <isomer@tvl.fyi>
Reviewed-by: kanepyork <rikingcoding@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/third_party/nix/src/nix/cat.cc b/third_party/nix/src/nix/cat.cc
index 49471100cf..9ead9a6ff6 100644
--- a/third_party/nix/src/nix/cat.cc
+++ b/third_party/nix/src/nix/cat.cc
@@ -21,7 +21,7 @@ struct MixCat : virtual Args {
   }
 };
 
-struct CmdCatStore : StoreCommand, MixCat {
+struct CmdCatStore final : StoreCommand, MixCat {
   CmdCatStore() { expectArg("path", &path); }
 
   std::string name() override { return "cat-store"; }
@@ -33,7 +33,7 @@ struct CmdCatStore : StoreCommand, MixCat {
   void run(ref<Store> store) override { cat(store->getFSAccessor()); }
 };
 
-struct CmdCatNar : StoreCommand, MixCat {
+struct CmdCatNar final : StoreCommand, MixCat {
   Path narPath;
 
   CmdCatNar() {