From f6709e90cd45e20ecd61a3ee2c9445ef6f51d6ea Mon Sep 17 00:00:00 2001
From: Winni Neessen <wn@neessen.net>
Date: Sun, 1 Jan 2023 14:25:00 +0100
Subject: [PATCH] Make golangci-lint happy by using `errors.As` instead of
 using type assertion on error (which can fail on wrapped errors)

---
 msg.go       | 8 ++++----
 senderror.go | 9 +++++----
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/msg.go b/msg.go
index 16b9c9b..320b427 100644
--- a/msg.go
+++ b/msg.go
@@ -969,11 +969,11 @@ func (m *Msg) HasSendError() bool {
 // SendErrorIsTemp returns true if the Msg experienced an error during the message delivery and the
 // corresponding error was of temporary nature and should be retried later
 func (m *Msg) SendErrorIsTemp() bool {
-	e, ok := m.sendError.(*SendError)
-	if !ok {
-		return false
+	var e *SendError
+	if errors.As(m.sendError, &e) {
+		return e.isTemp
 	}
-	return e.isTemp
+	return false
 }
 
 // SendError returns the senderror field of the Msg
diff --git a/senderror.go b/senderror.go
index b4fb404..264a318 100644
--- a/senderror.go
+++ b/senderror.go
@@ -5,6 +5,7 @@
 package mail
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -94,11 +95,11 @@ func (e *SendError) Error() string {
 
 // Is implements the errors.Is functionality and compares the SendErrReason
 func (e *SendError) Is(et error) bool {
-	t, ok := et.(*SendError)
-	if !ok {
-		return false
+	var t *SendError
+	if errors.As(et, &t) {
+		return e.Reason == t.Reason && e.isTemp == t.isTemp
 	}
-	return e.Reason == t.Reason && e.isTemp == t.isTemp
+	return false
 }
 
 // String implements the Stringer interface for the SendErrReason