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, 3 insertions, 3 deletions

diff --git a/third_party/nix/src/nix/installables.cc b/third_party/nix/src/nix/installables.cc
index c6cfc4344f..5fe155ba16 100644
--- a/third_party/nix/src/nix/installables.cc
+++ b/third_party/nix/src/nix/installables.cc
@@ -98,7 +98,7 @@ Buildable Installable::toBuildable() {
   return std::move(buildables[0]);
 }
 
-struct InstallableStorePath : Installable {
+struct InstallableStorePath final : Installable {
   Path storePath;
 
   explicit InstallableStorePath(Path storePath)
@@ -158,7 +158,7 @@ struct InstallableValue : Installable {
   }
 };
 
-struct InstallableExpr : InstallableValue {
+struct InstallableExpr final : InstallableValue {
   std::string text;
 
   InstallableExpr(SourceExprCommand& cmd, std::string text)
@@ -173,7 +173,7 @@ struct InstallableExpr : InstallableValue {
   }
 };
 
-struct InstallableAttrPath : InstallableValue {
+struct InstallableAttrPath final : InstallableValue {
   std::string attrPath;
 
   InstallableAttrPath(SourceExprCommand& cmd, std::string attrPath)