golang errors.As()

main.go

package main

import (
	"errors"
	"fmt"
	"io/fs"
	"os"
)

// output: Failed at path: non-existing
func main() {
	if _, err := os.Open("non-existing"); err != nil {
		var pathError *fs.PathError
		if errors.As(err, &pathError) {
			fmt.Println("Failed at path:", pathError.Path)
		} else {
			fmt.Println(err)
		}
	}

}