diff --git a/bool.go b/bool.go
index bf239ec..86950a1 100644
--- a/bool.go
+++ b/bool.go
@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"encoding/json"
 	"errors"
+	// "fmt"
 )
 
 // Bool is an even nuller nullable bool.
@@ -52,6 +53,8 @@ func (b *Bool) UnmarshalJSON(data []byte) error {
 	case nil:
 		b.Valid = false
 		return nil
+		// default:
+		// 	err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Bool", v.(type).Name())
 	}
 	b.Valid = err == nil
 	return err
diff --git a/gin-bin b/gin-bin
new file mode 100644
index 0000000..0ef32d9
Binary files /dev/null and b/gin-bin differ
diff --git a/int.go b/int.go
index 81e39ad..692801b 100644
--- a/int.go
+++ b/int.go
@@ -3,6 +3,8 @@ package null
 import (
 	"database/sql"
 	"encoding/json"
+	"fmt"
+	"reflect"
 	"strconv"
 )
 
@@ -52,6 +54,8 @@ func (i *Int) UnmarshalJSON(data []byte) error {
 	case nil:
 		i.Valid = false
 		return nil
+	default:
+		err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Int", reflect.TypeOf(v).Name())
 	}
 	i.Valid = err == nil
 	return err