diff --git a/client/pkg/srv/srv.go b/client/pkg/srv/srv.go
index ec79799d7..15fda134d 100644
--- a/client/pkg/srv/srv.go
+++ b/client/pkg/srv/srv.go
@@ -33,7 +33,6 @@ var (
 // GetCluster gets the cluster information via DNS discovery.
 // Also sees each entry as a separate instance.
 func GetCluster(serviceScheme, service, name, dns string, apurls types.URLs) ([]string, error) {
-	tempName := int(0)
 	tcp2ap := make(map[string]url.URL)
 
 	// First, resolve the apurls
@@ -45,7 +44,10 @@ func GetCluster(serviceScheme, service, name, dns string, apurls types.URLs) ([]
 		tcp2ap[tcpAddr.String()] = url
 	}
 
-	var stringParts []string
+	var (
+		tempName    int
+		stringParts []string
+	)
 	updateNodeMap := func(service, scheme string) error {
 		_, addrs, err := lookupSRV(service, "tcp", dns)
 		if err != nil {
@@ -97,8 +99,10 @@ type SRVClients struct {
 
 // GetClient looks up the client endpoints for a service and domain.
 func GetClient(service, domain string, serviceName string) (*SRVClients, error) {
-	var urls []*url.URL
-	var srvs []*net.SRV
+	var (
+		urls []*url.URL
+		srvs []*net.SRV
+	)
 
 	updateURLs := func(service, scheme string) error {
 		_, addrs, err := lookupSRV(service, "tcp", domain)
diff --git a/client/pkg/testutil/recorder.go b/client/pkg/testutil/recorder.go
index 41349fec5..064e73138 100644
--- a/client/pkg/testutil/recorder.go
+++ b/client/pkg/testutil/recorder.go
@@ -87,7 +87,7 @@ type recorderStream struct {
 }
 
 func NewRecorderStream() Recorder {
-	return NewRecorderStreamWithWaitTimout(time.Duration(5 * time.Second))
+	return NewRecorderStreamWithWaitTimout(5 * time.Second)
 }
 
 func NewRecorderStreamWithWaitTimout(waitTimeout time.Duration) Recorder {
diff --git a/client/v2/members.go b/client/v2/members.go
index 5d638487c..5e868ec69 100644
--- a/client/v2/members.go
+++ b/client/v2/members.go
@@ -130,7 +130,7 @@ func (m *httpMembersAPI) List(ctx context.Context) ([]Member, error) {
 		return nil, err
 	}
 
-	return []Member(mCollection), nil
+	return mCollection, nil
 }
 
 func (m *httpMembersAPI) Add(ctx context.Context, peerURL string) (*Member, error) {
diff --git a/pkg/cpuutil/endian.go b/pkg/cpuutil/endian.go
index 06c06cd4a..d654b7476 100644
--- a/pkg/cpuutil/endian.go
+++ b/pkg/cpuutil/endian.go
@@ -19,7 +19,7 @@ import (
 	"unsafe"
 )
 
-const intWidth int = int(unsafe.Sizeof(0))
+const intWidth = int(unsafe.Sizeof(0))
 
 var byteOrder binary.ByteOrder
 
@@ -27,7 +27,7 @@ var byteOrder binary.ByteOrder
 func ByteOrder() binary.ByteOrder { return byteOrder }
 
 func init() {
-	i := int(0x1)
+	i := 0x1
 	if v := (*[intWidth]byte)(unsafe.Pointer(&i)); v[0] == 0 {
 		byteOrder = binary.BigEndian
 	} else {
diff --git a/pkg/flags/strings.go b/pkg/flags/strings.go
index a80190658..e3d131f79 100644
--- a/pkg/flags/strings.go
+++ b/pkg/flags/strings.go
@@ -49,5 +49,5 @@ func NewStringsValue(s string) (ss *StringsValue) {
 
 // StringsFromFlag returns a string slice from the flag.
 func StringsFromFlag(fs *flag.FlagSet, flagName string) []string {
-	return []string(*fs.Lookup(flagName).Value.(*StringsValue))
+	return *fs.Lookup(flagName).Value.(*StringsValue)
 }
diff --git a/pkg/flags/urls.go b/pkg/flags/urls.go
index 885d32f45..27db58743 100644
--- a/pkg/flags/urls.go
+++ b/pkg/flags/urls.go
@@ -62,5 +62,5 @@ func NewURLsValue(s string) *URLsValue {
 
 // URLsFromFlag returns a slices from url got from the flag.
 func URLsFromFlag(fs *flag.FlagSet, urlsFlagName string) []url.URL {
-	return []url.URL(*fs.Lookup(urlsFlagName).Value.(*URLsValue))
+	return *fs.Lookup(urlsFlagName).Value.(*URLsValue)
 }
diff --git a/pkg/traceutil/trace_test.go b/pkg/traceutil/trace_test.go
index 5b654cc0b..d56fe2953 100644
--- a/pkg/traceutil/trace_test.go
+++ b/pkg/traceutil/trace_test.go
@@ -237,7 +237,7 @@ func TestLogIfLong(t *testing.T) {
 	}{
 		{
 			name:      "When the duration is smaller than threshold",
-			threshold: time.Duration(200 * time.Millisecond),
+			threshold: 200 * time.Millisecond,
 			trace: &Trace{
 				operation: "Test",
 				startTime: time.Now().Add(-100 * time.Millisecond),
@@ -250,7 +250,7 @@ func TestLogIfLong(t *testing.T) {
 		},
 		{
 			name:      "When the duration is longer than threshold",
-			threshold: time.Duration(50 * time.Millisecond),
+			threshold: 50 * time.Millisecond,
 			trace: &Trace{
 				operation: "Test",
 				startTime: time.Now().Add(-100 * time.Millisecond),
@@ -265,7 +265,7 @@ func TestLogIfLong(t *testing.T) {
 		},
 		{
 			name:      "When not all steps are longer than step threshold",
-			threshold: time.Duration(50 * time.Millisecond),
+			threshold: 50 * time.Millisecond,
 			trace: &Trace{
 				operation: "Test",
 				startTime: time.Now().Add(-100 * time.Millisecond),
diff --git a/raft/raft.go b/raft/raft.go
index 6375abd2e..8ffa67928 100644
--- a/raft/raft.go
+++ b/raft/raft.go
@@ -109,7 +109,7 @@ var stmap = [...]string{
 }
 
 func (st StateType) String() string {
-	return stmap[uint64(st)]
+	return stmap[st]
 }
 
 // Config contains the parameters to start a raft.
diff --git a/raft/tracker/state.go b/raft/tracker/state.go
index 285b4b8f5..7dbdd63fa 100644
--- a/raft/tracker/state.go
+++ b/raft/tracker/state.go
@@ -39,4 +39,4 @@ var prstmap = [...]string{
 	"StateSnapshot",
 }
 
-func (st StateType) String() string { return prstmap[uint64(st)] }
+func (st StateType) String() string { return prstmap[st] }
diff --git a/server/embed/config.go b/server/embed/config.go
index b0fec532a..587cf642b 100644
--- a/server/embed/config.go
+++ b/server/embed/config.go
@@ -32,7 +32,7 @@ import (
 	"go.etcd.io/etcd/client/pkg/v3/tlsutil"
 	"go.etcd.io/etcd/client/pkg/v3/transport"
 	"go.etcd.io/etcd/client/pkg/v3/types"
-	"go.etcd.io/etcd/client/v3"
+	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/pkg/v3/flags"
 	"go.etcd.io/etcd/pkg/v3/netutil"
 	"go.etcd.io/etcd/server/v3/config"
@@ -572,7 +572,7 @@ func (cfg *configYAML) configFromFile(path string) error {
 			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-peer-urls: %v\n", err)
 			os.Exit(1)
 		}
-		cfg.LPUrls = []url.URL(u)
+		cfg.LPUrls = u
 	}
 
 	if cfg.LCUrlsJSON != "" {
@@ -581,7 +581,7 @@ func (cfg *configYAML) configFromFile(path string) error {
 			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-client-urls: %v\n", err)
 			os.Exit(1)
 		}
-		cfg.LCUrls = []url.URL(u)
+		cfg.LCUrls = u
 	}
 
 	if cfg.APUrlsJSON != "" {
@@ -590,7 +590,7 @@ func (cfg *configYAML) configFromFile(path string) error {
 			fmt.Fprintf(os.Stderr, "unexpected error setting up initial-advertise-peer-urls: %v\n", err)
 			os.Exit(1)
 		}
-		cfg.APUrls = []url.URL(u)
+		cfg.APUrls = u
 	}
 
 	if cfg.ACUrlsJSON != "" {
@@ -599,7 +599,7 @@ func (cfg *configYAML) configFromFile(path string) error {
 			fmt.Fprintf(os.Stderr, "unexpected error setting up advertise-peer-urls: %v\n", err)
 			os.Exit(1)
 		}
-		cfg.ACUrls = []url.URL(u)
+		cfg.ACUrls = u
 	}
 
 	if cfg.ListenMetricsUrlsJSON != "" {
@@ -608,7 +608,7 @@ func (cfg *configYAML) configFromFile(path string) error {
 			fmt.Fprintf(os.Stderr, "unexpected error setting up listen-metrics-urls: %v\n", err)
 			os.Exit(1)
 		}
-		cfg.ListenMetricsUrls = []url.URL(u)
+		cfg.ListenMetricsUrls = u
 	}
 
 	if cfg.CORSJSON != "" {
diff --git a/server/etcdserver/api/etcdhttp/peer_test.go b/server/etcdserver/api/etcdhttp/peer_test.go
index dae50fb4b..259cc4edb 100644
--- a/server/etcdserver/api/etcdhttp/peer_test.go
+++ b/server/etcdserver/api/etcdhttp/peer_test.go
@@ -46,12 +46,12 @@ type fakeCluster struct {
 func (c *fakeCluster) ID() types.ID         { return types.ID(c.id) }
 func (c *fakeCluster) ClientURLs() []string { return c.clientURLs }
 func (c *fakeCluster) Members() []*membership.Member {
-	var ms membership.MembersByID
+	ms := make(membership.MembersByID, 0, len(c.members))
 	for _, m := range c.members {
 		ms = append(ms, m)
 	}
 	sort.Sort(ms)
-	return []*membership.Member(ms)
+	return ms
 }
 func (c *fakeCluster) Member(id types.ID) *membership.Member { return c.members[uint64(id)] }
 func (c *fakeCluster) Version() *semver.Version              { return nil }
diff --git a/server/etcdserver/api/membership/cluster.go b/server/etcdserver/api/membership/cluster.go
index 18ac1a35f..d5da50ad5 100644
--- a/server/etcdserver/api/membership/cluster.go
+++ b/server/etcdserver/api/membership/cluster.go
@@ -130,7 +130,7 @@ func (c *RaftCluster) Members() []*Member {
 		ms = append(ms, m.Clone())
 	}
 	sort.Sort(ms)
-	return []*Member(ms)
+	return ms
 }
 
 func (c *RaftCluster) Member(id types.ID) *Member {
@@ -149,7 +149,7 @@ func (c *RaftCluster) VotingMembers() []*Member {
 		}
 	}
 	sort.Sort(ms)
-	return []*Member(ms)
+	return ms
 }
 
 // MemberByName returns a Member with the given name if exists.
diff --git a/server/storage/util.go b/server/storage/util.go
index 252e74f92..57a12f0e6 100644
--- a/server/storage/util.go
+++ b/server/storage/util.go
@@ -146,5 +146,5 @@ func GetEffectiveNodeIDsFromWalEntries(lg *zap.Logger, snap *raftpb.Snapshot, en
 		sids = append(sids, id)
 	}
 	sort.Sort(sids)
-	return []uint64(sids)
+	return sids
 }
diff --git a/tests/e2e/v3_curl_test.go b/tests/e2e/v3_curl_test.go
index 10e996a2c..4777dc30a 100644
--- a/tests/e2e/v3_curl_test.go
+++ b/tests/e2e/v3_curl_test.go
@@ -203,7 +203,7 @@ func testV3CurlAuth(cx ctlCtx) {
 	}
 
 	// create root role
-	rolereq, err := json.Marshal(&pb.AuthRoleAddRequest{Name: string("root")})
+	rolereq, err := json.Marshal(&pb.AuthRoleAddRequest{Name: "root"})
 	testutil.AssertNil(cx.t, err)
 
 	if err = e2e.CURLPost(cx.epc, e2e.CURLReq{Endpoint: path.Join(p, "/auth/role/add"), Value: string(rolereq), Expected: "revision"}); err != nil {
@@ -221,7 +221,7 @@ func testV3CurlAuth(cx ctlCtx) {
 	}
 
 	// enable auth
-	if err = e2e.CURLPost(cx.epc, e2e.CURLReq{Endpoint: path.Join(p, "/auth/enable"), Value: string("{}"), Expected: "revision"}); err != nil {
+	if err = e2e.CURLPost(cx.epc, e2e.CURLReq{Endpoint: path.Join(p, "/auth/enable"), Value: "{}", Expected: "revision"}); err != nil {
 		cx.t.Fatalf("failed testV3CurlAuth enable auth with curl using prefix (%s) (%v)", p, err)
 	}