style: kratos interface check (#2441)

* style: kratos interface check

* fix: kratos interface check

contrib/registry/consul/registry.go

@@ -7,14 +7,14 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/go-kratos/kratos/v2/registry"
-
 	"github.com/hashicorp/consul/api"
+
+	"github.com/go-kratos/kratos/v2/registry"
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 // Option is consul registry option.

contrib/registry/etcd/registry.go

@@ -12,8 +12,8 @@ import (
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 // Option is etcd registry option.

contrib/registry/eureka/register.go

@@ -11,8 +11,8 @@ import (
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 type Option func(o *Registry)

contrib/registry/zookeeper/register.go

@@ -12,8 +12,8 @@ import (
 )
 
 var (
-	_ registry.Registrar = &Registry{}
-	_ registry.Discovery = &Registry{}
+	_ registry.Registrar = (*Registry)(nil)
+	_ registry.Discovery = (*Registry)(nil)
 )
 
 // Option is etcd registry option.

transport/grpc/balancer.go

@@ -1,13 +1,13 @@
 package grpc
 
 import (
-	"github.com/go-kratos/kratos/v2/registry"
-	"github.com/go-kratos/kratos/v2/selector"
-	"github.com/go-kratos/kratos/v2/transport"
-
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/balancer/base"
 	"google.golang.org/grpc/metadata"
+
+	"github.com/go-kratos/kratos/v2/registry"
+	"github.com/go-kratos/kratos/v2/selector"
+	"github.com/go-kratos/kratos/v2/transport"
 )
 
 const (
@@ -15,8 +15,8 @@ const (
 )
 
 var (
-	_ base.PickerBuilder = &balancerBuilder{}
-	_ balancer.Picker    = &balancerPicker{}
+	_ base.PickerBuilder = (*balancerBuilder)(nil)
+	_ balancer.Picker    = (*balancerPicker)(nil)
 )
 
 func init() {