diff --git a/client/client.go b/client/client.go
index e6681b403..28fc2784b 100644
--- a/client/client.go
+++ b/client/client.go
@@ -36,8 +36,8 @@ import (
 type status int
 
 const (
-	deactivated status = 0
-	activated   status = 1
+	deactivated status = iota
+	activated
 )
 
 var (
diff --git a/pkg/document/internal_document.go b/pkg/document/internal_document.go
index 3024db576..278fbfba7 100644
--- a/pkg/document/internal_document.go
+++ b/pkg/document/internal_document.go
@@ -31,11 +31,11 @@ type stateType int
 const (
 	// Detached means that the document is not attached to the client.
 	// The actor of the ticket is created without being assigned.
-	Detached stateType = 0
+	Detached stateType = iota
 
 	// Attached means that this document is attached to the client.
 	// The actor of the ticket is created with being assigned by the client.
-	Attached stateType = 1
+	Attached
 )
 
 // InternalDocument represents a document in MongoDB and contains logical clocks.
diff --git a/pkg/document/json/primitive.go b/pkg/document/json/primitive.go
index 7e8156e28..8fc1b3308 100644
--- a/pkg/document/json/primitive.go
+++ b/pkg/document/json/primitive.go
@@ -28,14 +28,14 @@ import (
 type ValueType int
 
 const (
-	Null    ValueType = 0
-	Boolean ValueType = 1
-	Integer ValueType = 2
-	Long    ValueType = 3
-	Double  ValueType = 4
-	String  ValueType = 5
-	Bytes   ValueType = 6
-	Date    ValueType = 7
+	Null ValueType = iota
+	Boolean
+	Integer
+	Long
+	Double
+	String
+	Bytes
+	Date
 )
 
 // ValueFromBytes parses the given bytes into value.