Not able to convert err into go-sqlite3.Error

I am trying to convert an err in Go to go-sqlite3.Error, but it fails always. Above image represents the snapshot of my debug windows, which shows that the err is of type go-sqlite3.Error

I am using below code to type cast.

import (
    "github.com/mattn/go-sqlite3"
)

if err != nil {
    if sqlite3Err, ok := err.(*sqlite3.Error); ok {
        if sqlite3Err.Code == sqlite3.ErrConstraint && sqlite3Err.ExtendedCode == 1555 {
            // SQLITE3 ERROR 1555 : PRIMARY KEY CONSTRAINT ERROR
            return errors.New("Log Error")
        }
    }

try the following example. err.(*sqlite3.Error) is changed to err.(sqlite3.Error)

if sqlite3Err, ok := err.(sqlite3.Error); ok {
    if sqlite3Err.Code == sqlite3.ErrConstraint &&
        sqlite3Err.ExtendedCode == 1555 {
        // logic 
    }
}