upstream: use defer

upstream/upstream_dnscrypt.go

@@ -124,6 +124,13 @@ func (p *dnsCrypt) exchangeDNSCrypt(m *dns.Msg) (resp *dns.Msg, err error) {
 func (p *dnsCrypt) resetClient() (client *dnscrypt.Client, ri *dnscrypt.ResolverInfo, err error) {
 	addr := p.Address()
 
+	defer func() {
+		p.mu.Lock()
+		defer p.mu.Unlock()
+
+		p.client, p.resolverInfo = client, ri
+	}()
+
 	// Use UDP for DNSCrypt upstreams by default.
 	client = &dnscrypt.Client{Timeout: p.timeout, Net: networkUDP}
 	ri, err = client.Dial(addr)
@@ -140,16 +147,5 @@ func (p *dnsCrypt) resetClient() (client *dnscrypt.Client, ri *dnscrypt.Resolver
 		}
 	}
 
-	func() {
-		p.mu.Lock()
-		defer p.mu.Unlock()
-
-		// Update the client and server info in an anonymous function to make
-		// ineffassign do its job.
-		//
-		// See https://github.com/gordonklaus/ineffassign/issues/82.
-		p.client, p.resolverInfo = client, ri
-	}()
-
 	return client, ri, err
 }