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/hash.cc b/third_party/nix/src/nix/hash.cc
index 935faec9d5..521f97d53a 100644
--- a/third_party/nix/src/nix/hash.cc
+++ b/third_party/nix/src/nix/hash.cc
@@ -6,7 +6,7 @@
 
 using namespace nix;
 
-struct CmdHash : Command {
+struct CmdHash final : Command {
   enum Mode { mFile, mPath };
   Mode mode;
   Base base = SRI;
@@ -47,7 +47,7 @@ struct CmdHash : Command {
 static RegisterCommand r1(make_ref<CmdHash>(CmdHash::mFile));
 static RegisterCommand r2(make_ref<CmdHash>(CmdHash::mPath));
 
-struct CmdToBase : Command {
+struct CmdToBase final : Command {
   Base base;
   HashType ht = htUnknown;
   std::vector<std::string> args;