diff --git a/registry/registry.go b/registry/registry.go
index e72e945..675ceb8 100644
--- a/registry/registry.go
+++ b/registry/registry.go
@@ -117,27 +117,31 @@ func (cr *defaultComponentRegistry) GetInstance(t reflect.Type) (interface{}, er
 		return nil, fmt.Errorf("DI: t[reflect.Type] must be pointer of struct")
 	}
 
-	var err error
+	var (
+		td   *TypeDefinition
+		comV interface{}
+		ok   bool
+		err  error
+	)
 
 	rt, _, _ := cur.GetTypeInfo(t)
-	td, ok := cr.definitionByType[rt]
-	if !ok {
-		td, err = cr.buildDefinition(t)
-		if nil != err {
+	if td, ok = cr.definitionByType[rt]; !ok {
+		if td, err = cr.buildDefinition(t); nil != err {
 			return nil, fmt.Errorf("DI: %v", err)
 		}
 	}
 
-	comV, ok := cr.instanceByType[td.RealType]
-	if ok {
+	if comV, ok = cr.instanceByType[td.RealType]; ok {
 		return comV, nil
 	}
 
 	v := reflect.New(rt)
 	rv := v.Elem()
 
-	var annotation cda.Annotation
-	var fV interface{}
+	var (
+		annotation cda.Annotation
+		fV         interface{}
+	)
 
 	for _, fd := range td.Fields {
 		f := rv.FieldByName(fd.FieldName)
@@ -150,8 +154,7 @@ func (cr *defaultComponentRegistry) GetInstance(t reflect.Type) (interface{}, er
 		}
 
 		if annotation = fd.GetAnnotationByType(reflect.TypeOf((*cdia.Inject)(nil)), false); nil != annotation {
-			fV, err = cr.GetInstance(fd.Type)
-			if nil != err {
+			if fV, err = cr.GetInstance(fd.Type); nil != err {
 				return nil, err
 			}
 		}
@@ -161,8 +164,7 @@ func (cr *defaultComponentRegistry) GetInstance(t reflect.Type) (interface{}, er
 			if "" == n {
 				n = fd.FieldName
 			}
-			fV, err = cr.GetInstanceByName(n)
-			if nil != err {
+			if fV, err = cr.GetInstanceByName(n); nil != err {
 				return nil, err
 			}
 		}
@@ -201,8 +203,7 @@ func (cr *defaultComponentRegistry) GetInstances(ts []reflect.Type) ([]interface
 	)
 	instances := make([]interface{}, 0)
 	for _, t := range ts {
-		i, err = cr.GetInstance(t)
-		if nil != err {
+		if i, err = cr.GetInstance(t); nil != err {
 			return nil, err
 		}
 		instances = append(instances, i)
@@ -225,8 +226,7 @@ func (cr *defaultComponentRegistry) GetInstancesByAnnotationName(n string) ([]in
 
 	for _, td := range cr.definitionByType {
 		if nil != td.GetAnnotation(n) {
-			i, err = cr.GetInstance(td.Type)
-			if nil != err {
+			if i, err = cr.GetInstance(td.Type); nil != err {
 				return nil, err
 			}
 			instances = append(instances, i)