diff --git a/interop/client/client.go b/interop/client/client.go
index c9245797ce39..379fd017c27e 100644
--- a/interop/client/client.go
+++ b/interop/client/client.go
@@ -349,10 +349,10 @@ func main() {
 		interop.DoCustomMetadata(ctx, tc)
 		logger.Infoln("CustomMetadata done")
 	case "unimplemented_method":
-		interop.DoUnimplementedMethod(conn, ctx)
+		interop.DoUnimplementedMethod(ctx, conn)
 		logger.Infoln("UnimplementedMethod done")
 	case "unimplemented_service":
-		interop.DoUnimplementedService(testgrpc.NewUnimplementedServiceClient(conn), ctx)
+		interop.DoUnimplementedService(ctx, testgrpc.NewUnimplementedServiceClient(conn))
 		logger.Infoln("UnimplementedService done")
 	case "pick_first_unary":
 		interop.DoPickFirstUnary(ctx, tc)
diff --git a/interop/test_utils.go b/interop/test_utils.go
index f075f0753bbd..302071e34088 100644
--- a/interop/test_utils.go
+++ b/interop/test_utils.go
@@ -634,7 +634,7 @@ func DoSpecialStatusMessage(ctx context.Context, tc testgrpc.TestServiceClient,
 }
 
 // DoUnimplementedService attempts to call a method from an unimplemented service.
-func DoUnimplementedService(tc testgrpc.UnimplementedServiceClient, ctx context.Context) {
+func DoUnimplementedService(ctx context.Context, tc testgrpc.UnimplementedServiceClient) {
 	_, err := tc.UnimplementedCall(ctx, &testpb.Empty{})
 	if status.Code(err) != codes.Unimplemented {
 		logger.Fatalf("%v.UnimplementedCall() = _, %v, want _, %v", tc, status.Code(err), codes.Unimplemented)
@@ -642,7 +642,7 @@ func DoUnimplementedService(tc testgrpc.UnimplementedServiceClient, ctx context.
 }
 
 // DoUnimplementedMethod attempts to call an unimplemented method.
-func DoUnimplementedMethod(cc *grpc.ClientConn, ctx context.Context) {
+func DoUnimplementedMethod(ctx context.Context, cc *grpc.ClientConn) {
 	var req, reply proto.Message
 	if err := cc.Invoke(ctx, "/grpc.testing.TestService/UnimplementedCall", req, reply); err == nil || status.Code(err) != codes.Unimplemented {
 		logger.Fatalf("ClientConn.Invoke(_, _, _, _, _) = %v, want error code %s", err, codes.Unimplemented)
diff --git a/vet.sh b/vet.sh
index 1d3e307a214d..7a33c215b588 100755
--- a/vet.sh
+++ b/vet.sh
@@ -41,7 +41,7 @@ if [[ "$1" = "-install" ]]; then
   popd
   if [[ -z "${VET_SKIP_PROTO}" ]]; then
     if [[ "${GITHUB_ACTIONS}" = "true" ]]; then
-      PROTOBUF_VERSION=25.2 # a.k.a v4.22.0 in pb.go files.
+      PROTOBUF_VERSION=25.2 # a.k.a. v4.22.0 in pb.go files.
       PROTOC_FILENAME=protoc-${PROTOBUF_VERSION}-linux-x86_64.zip
       pushd /home/runner/go
       wget https://github.com/google/protobuf/releases/download/v${PROTOBUF_VERSION}/${PROTOC_FILENAME}