diff --git a/cmd/clef/main.go b/cmd/clef/main.go
index f4d94f0274..85ec5647cd 100644
--- a/cmd/clef/main.go
+++ b/cmd/clef/main.go
@@ -767,8 +767,8 @@ func testExternalUI(api *core.SignerAPI) {
 		data := `{"types":{"EIP712Domain":[{"name":"name","type":"string"},{"name":"version","type":"string"},{"name":"chainId","type":"uint256"},{"name":"verifyingContract","type":"address"}],"Person":[{"name":"name","type":"string"},{"name":"test","type":"uint8"},{"name":"wallet","type":"address"}],"Mail":[{"name":"from","type":"Person"},{"name":"to","type":"Person"},{"name":"contents","type":"string"}]},"primaryType":"Mail","domain":{"name":"Ether Mail","version":"1","chainId":"1","verifyingContract":"0xCCCcccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC"},"message":{"from":{"name":"Cow","test":"3","wallet":"0xcD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"},"to":{"name":"Bob","wallet":"0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB","test":"2"},"contents":"Hello, Bob!"}}`
 		//_, err := api.SignData(ctx, accounts.MimetypeTypedData, *addr, hexutil.Encode([]byte(data)))
 		var typedData core.TypedData
-		err := json.Unmarshal([]byte(data), &typedData)
-		_, err = api.SignTypedData(ctx, *addr, typedData)
+		json.Unmarshal([]byte(data), &typedData)
+		_, err := api.SignTypedData(ctx, *addr, typedData)
 		expectApprove("sign 712 typed data", err)
 	}
 	{ // Sign data test - plain text
diff --git a/cmd/geth/retesteth.go b/cmd/geth/retesteth.go
index 8453f753fb..f20f2295ac 100644
--- a/cmd/geth/retesteth.go
+++ b/cmd/geth/retesteth.go
@@ -768,10 +768,10 @@ func (api *RetestethAPI) StorageRangeAt(ctx context.Context,
 			}
 			// Ensure any modifications are committed to the state
 			// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
-			root = statedb.IntermediateRoot(vmenv.ChainConfig().IsEIP158(block.Number()))
+			_ = statedb.IntermediateRoot(vmenv.ChainConfig().IsEIP158(block.Number()))
 			if idx == int(txIndex) {
 				// This is to make sure root can be opened by OpenTrie
-				root, err = statedb.Commit(vmenv.ChainConfig().IsEIP158(block.Number()))
+				_, err = statedb.Commit(vmenv.ChainConfig().IsEIP158(block.Number()))
 				if err != nil {
 					return StorageRangeResult{}, err
 				}
@@ -832,7 +832,7 @@ func retesteth(ctx *cli.Context) error {
 	log.Info("Welcome to retesteth!")
 	// register signer API with server
 	var (
-		extapiURL = "n/a"
+		extapiURL string
 	)
 	apiImpl := &RetestethAPI{}
 	var testApi RetestethTestAPI = apiImpl
diff --git a/contracts/checkpointoracle/oracle_test.go b/contracts/checkpointoracle/oracle_test.go
index bc2dbb6040..5986ea0d86 100644
--- a/contracts/checkpointoracle/oracle_test.go
+++ b/contracts/checkpointoracle/oracle_test.go
@@ -241,9 +241,9 @@ func TestCheckpointRegister(t *testing.T) {
 
 	// Test transaction replay protection
 	validateOperation(t, c, contractBackend, func() {
-		number, hash := getRecent()
+		number, _ := getRecent()
 		v, r, s := collectSig(0, checkpoint0.Hash(), 2, nil)
-		hash = common.HexToHash("deadbeef")
+		hash := common.HexToHash("deadbeef")
 		c.SetCheckpoint(transactOpts, number, hash, checkpoint0.Hash(), 0, v, r, s)
 	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
 		return assert(0, emptyHash, big.NewInt(0))
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 874e6e07f6..edd0eb4d95 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -997,7 +997,7 @@ func (d *Downloader) fetchHeaders(p *peerConnection, from uint64, pivot uint64)
 				// chain errors.
 				if n := len(headers); n > 0 {
 					// Retrieve the current head we're at
-					head := uint64(0)
+					var head uint64
 					if d.mode == LightSync {
 						head = d.lightchain.CurrentHeader().Number.Uint64()
 					} else {
diff --git a/p2p/simulations/adapters/exec.go b/p2p/simulations/adapters/exec.go
index 4f17efc334..5eb0a31566 100644
--- a/p2p/simulations/adapters/exec.go
+++ b/p2p/simulations/adapters/exec.go
@@ -416,7 +416,7 @@ func startExecNodeStack() (*node.Node, error) {
 	}
 
 	// create enode record
-	nodeTcpConn, err := net.ResolveTCPAddr("tcp", conf.Stack.P2P.ListenAddr)
+	nodeTcpConn, _ := net.ResolveTCPAddr("tcp", conf.Stack.P2P.ListenAddr)
 	if nodeTcpConn.IP == nil {
 		nodeTcpConn.IP = net.IPv4(127, 0, 0, 1)
 	}
diff --git a/signer/core/signed_data.go b/signer/core/signed_data.go
index 4d19ca710c..f512be7cea 100644
--- a/signer/core/signed_data.go
+++ b/signer/core/signed_data.go
@@ -484,7 +484,7 @@ func (typedData *TypedData) EncodeData(primaryType string, data map[string]inter
 
 func parseInteger(encType string, encValue interface{}) (*big.Int, error) {
 	var (
-		length = 0
+		length int
 		signed = strings.HasPrefix(encType, "int")
 		b      *big.Int
 	)
diff --git a/whisper/mailserver/server_test.go b/whisper/mailserver/server_test.go
index edb817cc75..4f80e550aa 100644
--- a/whisper/mailserver/server_test.go
+++ b/whisper/mailserver/server_test.go
@@ -172,7 +172,7 @@ func singleRequest(t *testing.T, server *WMailServer, env *whisper.Envelope, p *
 	}
 
 	src[0]++
-	ok, lower, upper, bloom = server.validateRequest(src, request)
+	ok, lower, upper, _ = server.validateRequest(src, request)
 	if !ok {
 		// request should be valid regardless of signature
 		t.Fatalf("request validation false negative, seed: %d (lower: %d, upper: %d).", seed, lower, upper)
diff --git a/whisper/whisperv6/peer.go b/whisper/whisperv6/peer.go
index 621d512081..4451f14958 100644
--- a/whisper/whisperv6/peer.go
+++ b/whisper/whisperv6/peer.go
@@ -130,7 +130,7 @@ func (peer *Peer) handshake() error {
 		}
 	}
 
-	isRemotePeerLightNode, err := s.Bool()
+	isRemotePeerLightNode, _ := s.Bool()
 	if isRemotePeerLightNode && isLightNode && isRestrictedLightNodeConnection {
 		return fmt.Errorf("peer [%x] is useless: two light client communication restricted", peer.ID())
 	}