diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index 76c51a40c1..7b605e1c1e 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -66,7 +66,7 @@ type SimulatedBackend struct {
 // NewSimulatedBackend creates a new binding backend using a simulated blockchain
 // for testing purposes.
 func NewSimulatedBackend(alloc core.GenesisAlloc) *SimulatedBackend {
-	database, _ := ethdb.NewMemDatabase()
+	database := ethdb.NewMemDatabase()
 	genesis := core.Genesis{Config: params.AllEthashProtocolChanges, Alloc: alloc}
 	genesis.MustCommit(database)
 	blockchain, _ := core.NewBlockChain(database, nil, genesis.Config, ethash.NewFaker(), vm.Config{})
diff --git a/build/ci.go b/build/ci.go
index 204c206752..79dcc146c3 100644
--- a/build/ci.go
+++ b/build/ci.go
@@ -755,14 +755,18 @@ func doAndroidArchive(cmdline []string) {
 	os.Rename(archive, meta.Package+".aar")
 	if *signer != "" && *deploy != "" {
 		// Import the signing key into the local GPG instance
-		if b64key := os.Getenv(*signer); b64key != "" {
-			key, err := base64.StdEncoding.DecodeString(b64key)
-			if err != nil {
-				log.Fatalf("invalid base64 %s", *signer)
-			}
-			gpg := exec.Command("gpg", "--import")
-			gpg.Stdin = bytes.NewReader(key)
-			build.MustRun(gpg)
+		b64key := os.Getenv(*signer)
+		key, err := base64.StdEncoding.DecodeString(b64key)
+		if err != nil {
+			log.Fatalf("invalid base64 %s", *signer)
+		}
+		gpg := exec.Command("gpg", "--import")
+		gpg.Stdin = bytes.NewReader(key)
+		build.MustRun(gpg)
+
+		keyID, err := build.PGPKeyID(string(key))
+		if err != nil {
+			log.Fatal(err)
 		}
 		// Upload the artifacts to Sonatype and/or Maven Central
 		repo := *deploy + "/service/local/staging/deploy/maven2"
@@ -771,6 +775,7 @@ func doAndroidArchive(cmdline []string) {
 		}
 		build.MustRunCommand("mvn", "gpg:sign-and-deploy-file", "-e", "-X",
 			"-settings=build/mvn.settings", "-Durl="+repo, "-DrepositoryId=ossrh",
+			"-Dgpg.keyname="+keyID,
 			"-DpomFile="+meta.Package+".pom", "-Dfile="+meta.Package+".aar")
 	}
 }
diff --git a/cmd/clef/main.go b/cmd/clef/main.go
index 9a1ae91acb..348bcb22f6 100644
--- a/cmd/clef/main.go
+++ b/cmd/clef/main.go
@@ -47,11 +47,11 @@ import (
 	"gopkg.in/urfave/cli.v1"
 )
 
-// ExternalApiVersion -- see extapi_changelog.md
-const ExternalApiVersion = "2.0.0"
+// ExternalAPIVersion -- see extapi_changelog.md
+const ExternalAPIVersion = "2.0.0"
 
-// InternalApiVersion -- see intapi_changelog.md
-const InternalApiVersion = "2.0.0"
+// InternalAPIVersion -- see intapi_changelog.md
+const InternalAPIVersion = "2.0.0"
 
 const legalWarning = `
 WARNING! 
@@ -398,10 +398,10 @@ func signer(c *cli.Context) error {
 	}
 	// register signer API with server
 	var (
-		extapiUrl = "n/a"
-		ipcApiUrl = "n/a"
+		extapiURL = "n/a"
+		ipcapiURL = "n/a"
 	)
-	rpcApi := []rpc.API{
+	rpcAPI := []rpc.API{
 		{
 			Namespace: "account",
 			Public:    true,
@@ -415,12 +415,12 @@ func signer(c *cli.Context) error {
 
 		// start http server
 		httpEndpoint := fmt.Sprintf("%s:%d", c.String(utils.RPCListenAddrFlag.Name), c.Int(rpcPortFlag.Name))
-		listener, _, err := rpc.StartHTTPEndpoint(httpEndpoint, rpcApi, []string{"account"}, cors, vhosts)
+		listener, _, err := rpc.StartHTTPEndpoint(httpEndpoint, rpcAPI, []string{"account"}, cors, vhosts)
 		if err != nil {
 			utils.Fatalf("Could not start RPC api: %v", err)
 		}
-		extapiUrl = fmt.Sprintf("http://%s", httpEndpoint)
-		log.Info("HTTP endpoint opened", "url", extapiUrl)
+		extapiURL = fmt.Sprintf("http://%s", httpEndpoint)
+		log.Info("HTTP endpoint opened", "url", extapiURL)
 
 		defer func() {
 			listener.Close()
@@ -430,19 +430,19 @@ func signer(c *cli.Context) error {
 	}
 	if !c.Bool(utils.IPCDisabledFlag.Name) {
 		if c.IsSet(utils.IPCPathFlag.Name) {
-			ipcApiUrl = c.String(utils.IPCPathFlag.Name)
+			ipcapiURL = c.String(utils.IPCPathFlag.Name)
 		} else {
-			ipcApiUrl = filepath.Join(configDir, "clef.ipc")
+			ipcapiURL = filepath.Join(configDir, "clef.ipc")
 		}
 
-		listener, _, err := rpc.StartIPCEndpoint(ipcApiUrl, rpcApi)
+		listener, _, err := rpc.StartIPCEndpoint(ipcapiURL, rpcAPI)
 		if err != nil {
 			utils.Fatalf("Could not start IPC api: %v", err)
 		}
-		log.Info("IPC endpoint opened", "url", ipcApiUrl)
+		log.Info("IPC endpoint opened", "url", ipcapiURL)
 		defer func() {
 			listener.Close()
-			log.Info("IPC endpoint closed", "url", ipcApiUrl)
+			log.Info("IPC endpoint closed", "url", ipcapiURL)
 		}()
 
 	}
@@ -453,10 +453,10 @@ func signer(c *cli.Context) error {
 	}
 	ui.OnSignerStartup(core.StartupInfo{
 		Info: map[string]interface{}{
-			"extapi_version": ExternalApiVersion,
-			"intapi_version": InternalApiVersion,
-			"extapi_http":    extapiUrl,
-			"extapi_ipc":     ipcApiUrl,
+			"extapi_version": ExternalAPIVersion,
+			"intapi_version": InternalAPIVersion,
+			"extapi_http":    extapiURL,
+			"extapi_ipc":     ipcapiURL,
 		},
 	})
 
diff --git a/cmd/evm/json_logger.go b/cmd/evm/json_logger.go
index 0e7a911896..f16424fbe6 100644
--- a/cmd/evm/json_logger.go
+++ b/cmd/evm/json_logger.go
@@ -32,6 +32,8 @@ type JSONLogger struct {
 	cfg     *vm.LogConfig
 }
 
+// NewJSONLogger creates a new EVM tracer that prints execution steps as JSON objects
+// into the provided stream.
 func NewJSONLogger(cfg *vm.LogConfig, writer io.Writer) *JSONLogger {
 	return &JSONLogger{json.NewEncoder(writer), cfg}
 }
diff --git a/cmd/evm/runner.go b/cmd/evm/runner.go
index 99919304ae..7138a9ddd4 100644
--- a/cmd/evm/runner.go
+++ b/cmd/evm/runner.go
@@ -98,14 +98,13 @@ func runCmd(ctx *cli.Context) error {
 	}
 	if ctx.GlobalString(GenesisFlag.Name) != "" {
 		gen := readGenesis(ctx.GlobalString(GenesisFlag.Name))
-		db, _ := ethdb.NewMemDatabase()
+		db := ethdb.NewMemDatabase()
 		genesis := gen.ToBlock(db)
 		statedb, _ = state.New(genesis.Root(), state.NewDatabase(db))
 		chainConfig = gen.Config
 		blockNumber = gen.Number
 	} else {
-		db, _ := ethdb.NewMemDatabase()
-		statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		statedb, _ = state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	}
 	if ctx.GlobalString(SenderFlag.Name) != "" {
 		sender = common.HexToAddress(ctx.GlobalString(SenderFlag.Name))
diff --git a/cmd/evm/staterunner.go b/cmd/evm/staterunner.go
index 071ea94ad0..6d5ff069f6 100644
--- a/cmd/evm/staterunner.go
+++ b/cmd/evm/staterunner.go
@@ -38,6 +38,8 @@ var stateTestCommand = cli.Command{
 	ArgsUsage: "<file>",
 }
 
+// StatetestResult contains the execution status after running a state test, any
+// error that might have occurred and a dump of the final state if requested.
 type StatetestResult struct {
 	Name  string      `json:"name"`
 	Pass  bool        `json:"pass"`
diff --git a/cmd/geth/accountcmd.go b/cmd/geth/accountcmd.go
index 0db5c4ce0f..071be85397 100644
--- a/cmd/geth/accountcmd.go
+++ b/cmd/geth/accountcmd.go
@@ -340,7 +340,7 @@ func importWallet(ctx *cli.Context) error {
 	if len(keyfile) == 0 {
 		utils.Fatalf("keyfile must be given as argument")
 	}
-	keyJson, err := ioutil.ReadFile(keyfile)
+	keyJSON, err := ioutil.ReadFile(keyfile)
 	if err != nil {
 		utils.Fatalf("Could not read wallet file: %v", err)
 	}
@@ -349,7 +349,7 @@ func importWallet(ctx *cli.Context) error {
 	passphrase := getPassPhrase("", false, 0, utils.MakePasswordList(ctx))
 
 	ks := stack.AccountManager().Backends(keystore.KeyStoreType)[0].(*keystore.KeyStore)
-	acct, err := ks.ImportPreSaleKey(keyJson, passphrase)
+	acct, err := ks.ImportPreSaleKey(keyJSON, passphrase)
 	if err != nil {
 		utils.Fatalf("%v", err)
 	}
diff --git a/cmd/geth/bugcmd.go b/cmd/geth/bugcmd.go
index 51187ac90e..7e9a8ccc70 100644
--- a/cmd/geth/bugcmd.go
+++ b/cmd/geth/bugcmd.go
@@ -41,7 +41,7 @@ var bugCommand = cli.Command{
 	Category:  "MISCELLANEOUS COMMANDS",
 }
 
-const issueUrl = "https://github.com/ethereum/go-ethereum/issues/new"
+const issueURL = "https://github.com/ethereum/go-ethereum/issues/new"
 
 // reportBug reports a bug by opening a new URL to the go-ethereum GH issue
 // tracker and setting default values as the issue body.
@@ -58,8 +58,8 @@ func reportBug(ctx *cli.Context) error {
 	fmt.Fprintln(&buff, header)
 
 	// open a new GH issue
-	if !browser.Open(issueUrl + "?body=" + url.QueryEscape(buff.String())) {
-		fmt.Printf("Please file a new issue at %s using this template:\n\n%s", issueUrl, buff.String())
+	if !browser.Open(issueURL + "?body=" + url.QueryEscape(buff.String())) {
+		fmt.Printf("Please file a new issue at %s using this template:\n\n%s", issueURL, buff.String())
 	}
 	return nil
 }
diff --git a/consensus/clique/snapshot_test.go b/consensus/clique/snapshot_test.go
index 91fafcbe07..29a8379832 100644
--- a/consensus/clique/snapshot_test.go
+++ b/consensus/clique/snapshot_test.go
@@ -352,7 +352,7 @@ func TestVoting(t *testing.T) {
 			copy(genesis.ExtraData[extraVanity+j*common.AddressLength:], signer[:])
 		}
 		// Create a pristine blockchain with the genesis injected
-		db, _ := ethdb.NewMemDatabase()
+		db := ethdb.NewMemDatabase()
 		genesis.Commit(db)
 
 		// Assemble a chain of headers from the cast votes
diff --git a/core/bench_test.go b/core/bench_test.go
index ee30cfed0e..748aebe407 100644
--- a/core/bench_test.go
+++ b/core/bench_test.go
@@ -149,7 +149,7 @@ func benchInsertChain(b *testing.B, disk bool, gen func(int, *BlockGen)) {
 	// Create the database in memory or in a temporary directory.
 	var db ethdb.Database
 	if !disk {
-		db, _ = ethdb.NewMemDatabase()
+		db = ethdb.NewMemDatabase()
 	} else {
 		dir, err := ioutil.TempDir("", "eth-core-bench")
 		if err != nil {
diff --git a/core/block_validator_test.go b/core/block_validator_test.go
index e334b3c3cd..2a171218e3 100644
--- a/core/block_validator_test.go
+++ b/core/block_validator_test.go
@@ -32,7 +32,7 @@ import (
 func TestHeaderVerification(t *testing.T) {
 	// Create a simple chain to verify
 	var (
-		testdb, _ = ethdb.NewMemDatabase()
+		testdb    = ethdb.NewMemDatabase()
 		gspec     = &Genesis{Config: params.TestChainConfig}
 		genesis   = gspec.MustCommit(testdb)
 		blocks, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), testdb, 8, nil)
@@ -84,7 +84,7 @@ func TestHeaderConcurrentVerification32(t *testing.T) { testHeaderConcurrentVeri
 func testHeaderConcurrentVerification(t *testing.T, threads int) {
 	// Create a simple chain to verify
 	var (
-		testdb, _ = ethdb.NewMemDatabase()
+		testdb    = ethdb.NewMemDatabase()
 		gspec     = &Genesis{Config: params.TestChainConfig}
 		genesis   = gspec.MustCommit(testdb)
 		blocks, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), testdb, 8, nil)
@@ -156,7 +156,7 @@ func TestHeaderConcurrentAbortion32(t *testing.T) { testHeaderConcurrentAbortion
 func testHeaderConcurrentAbortion(t *testing.T, threads int) {
 	// Create a simple chain to verify
 	var (
-		testdb, _ = ethdb.NewMemDatabase()
+		testdb    = ethdb.NewMemDatabase()
 		gspec     = &Genesis{Config: params.TestChainConfig}
 		genesis   = gspec.MustCommit(testdb)
 		blocks, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), testdb, 1024, nil)
diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index c1638c31f8..89c071174f 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -569,11 +569,11 @@ func testInsertNonceError(t *testing.T, full bool) {
 func TestFastVsFullChains(t *testing.T) {
 	// Configure and generate a sample block chain
 	var (
-		gendb, _ = ethdb.NewMemDatabase()
-		key, _   = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
-		address  = crypto.PubkeyToAddress(key.PublicKey)
-		funds    = big.NewInt(1000000000)
-		gspec    = &Genesis{
+		gendb   = ethdb.NewMemDatabase()
+		key, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		address = crypto.PubkeyToAddress(key.PublicKey)
+		funds   = big.NewInt(1000000000)
+		gspec   = &Genesis{
 			Config: params.TestChainConfig,
 			Alloc:  GenesisAlloc{address: {Balance: funds}},
 		}
@@ -599,7 +599,7 @@ func TestFastVsFullChains(t *testing.T) {
 		}
 	})
 	// Import the chain as an archive node for the comparison baseline
-	archiveDb, _ := ethdb.NewMemDatabase()
+	archiveDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(archiveDb)
 	archive, _ := NewBlockChain(archiveDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer archive.Stop()
@@ -608,7 +608,7 @@ func TestFastVsFullChains(t *testing.T) {
 		t.Fatalf("failed to process block %d: %v", n, err)
 	}
 	// Fast import the chain as a non-archive node to test
-	fastDb, _ := ethdb.NewMemDatabase()
+	fastDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(fastDb)
 	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer fast.Stop()
@@ -657,12 +657,12 @@ func TestFastVsFullChains(t *testing.T) {
 func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	// Configure and generate a sample block chain
 	var (
-		gendb, _ = ethdb.NewMemDatabase()
-		key, _   = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
-		address  = crypto.PubkeyToAddress(key.PublicKey)
-		funds    = big.NewInt(1000000000)
-		gspec    = &Genesis{Config: params.TestChainConfig, Alloc: GenesisAlloc{address: {Balance: funds}}}
-		genesis  = gspec.MustCommit(gendb)
+		gendb   = ethdb.NewMemDatabase()
+		key, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		address = crypto.PubkeyToAddress(key.PublicKey)
+		funds   = big.NewInt(1000000000)
+		gspec   = &Genesis{Config: params.TestChainConfig, Alloc: GenesisAlloc{address: {Balance: funds}}}
+		genesis = gspec.MustCommit(gendb)
 	)
 	height := uint64(1024)
 	blocks, receipts := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), gendb, int(height), nil)
@@ -685,7 +685,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 		}
 	}
 	// Import the chain as an archive node and ensure all pointers are updated
-	archiveDb, _ := ethdb.NewMemDatabase()
+	archiveDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(archiveDb)
 
 	archive, _ := NewBlockChain(archiveDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{})
@@ -699,7 +699,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	assert(t, "archive", archive, height/2, height/2, height/2)
 
 	// Import the chain as a non-archive node and ensure all pointers are updated
-	fastDb, _ := ethdb.NewMemDatabase()
+	fastDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(fastDb)
 	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer fast.Stop()
@@ -719,7 +719,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	assert(t, "fast", fast, height/2, height/2, 0)
 
 	// Import the chain as a light node and ensure all pointers are updated
-	lightDb, _ := ethdb.NewMemDatabase()
+	lightDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(lightDb)
 
 	light, _ := NewBlockChain(lightDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{})
@@ -742,7 +742,7 @@ func TestChainTxReorgs(t *testing.T) {
 		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
 		addr2   = crypto.PubkeyToAddress(key2.PublicKey)
 		addr3   = crypto.PubkeyToAddress(key3.PublicKey)
-		db, _   = ethdb.NewMemDatabase()
+		db      = ethdb.NewMemDatabase()
 		gspec   = &Genesis{
 			Config:   params.TestChainConfig,
 			GasLimit: 3141592,
@@ -854,7 +854,7 @@ func TestLogReorgs(t *testing.T) {
 	var (
 		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
-		db, _   = ethdb.NewMemDatabase()
+		db      = ethdb.NewMemDatabase()
 		// this code generates a log
 		code    = common.Hex2Bytes("60606040525b7f24ec1d3ff24c2f6ff210738839dbc339cd45a5294d85c79361016243157aae7b60405180905060405180910390a15b600a8060416000396000f360606040526008565b00")
 		gspec   = &Genesis{Config: params.TestChainConfig, Alloc: GenesisAlloc{addr1: {Balance: big.NewInt(10000000000000)}}}
@@ -898,7 +898,7 @@ func TestLogReorgs(t *testing.T) {
 
 func TestReorgSideEvent(t *testing.T) {
 	var (
-		db, _   = ethdb.NewMemDatabase()
+		db      = ethdb.NewMemDatabase()
 		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
 		gspec   = &Genesis{
@@ -1026,7 +1026,7 @@ func TestCanonicalBlockRetrieval(t *testing.T) {
 func TestEIP155Transition(t *testing.T) {
 	// Configure and generate a sample block chain
 	var (
-		db, _      = ethdb.NewMemDatabase()
+		db         = ethdb.NewMemDatabase()
 		key, _     = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 		address    = crypto.PubkeyToAddress(key.PublicKey)
 		funds      = big.NewInt(1000000000)
@@ -1130,7 +1130,7 @@ func TestEIP155Transition(t *testing.T) {
 func TestEIP161AccountRemoval(t *testing.T) {
 	// Configure and generate a sample block chain
 	var (
-		db, _   = ethdb.NewMemDatabase()
+		db      = ethdb.NewMemDatabase()
 		key, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 		address = crypto.PubkeyToAddress(key.PublicKey)
 		funds   = big.NewInt(1000000000)
@@ -1202,7 +1202,7 @@ func TestBlockchainHeaderchainReorgConsistency(t *testing.T) {
 	// Generate a canonical chain to act as the main dataset
 	engine := ethash.NewFaker()
 
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	genesis := new(Genesis).MustCommit(db)
 	blocks, _ := GenerateChain(params.TestChainConfig, genesis, engine, db, 64, func(i int, b *BlockGen) { b.SetCoinbase(common.Address{1}) })
 
@@ -1218,7 +1218,7 @@ func TestBlockchainHeaderchainReorgConsistency(t *testing.T) {
 	}
 	// Import the canonical and fork chain side by side, verifying the current block
 	// and current header consistency
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	new(Genesis).MustCommit(diskdb)
 
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{})
@@ -1247,7 +1247,7 @@ func TestTrieForkGC(t *testing.T) {
 	// Generate a canonical chain to act as the main dataset
 	engine := ethash.NewFaker()
 
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	genesis := new(Genesis).MustCommit(db)
 	blocks, _ := GenerateChain(params.TestChainConfig, genesis, engine, db, 2*triesInMemory, func(i int, b *BlockGen) { b.SetCoinbase(common.Address{1}) })
 
@@ -1262,7 +1262,7 @@ func TestTrieForkGC(t *testing.T) {
 		forks[i] = fork[0]
 	}
 	// Import the canonical and fork chain side by side, forcing the trie cache to cache both
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	new(Genesis).MustCommit(diskdb)
 
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{})
@@ -1293,7 +1293,7 @@ func TestLargeReorgTrieGC(t *testing.T) {
 	// Generate the original common chain segment and the two competing forks
 	engine := ethash.NewFaker()
 
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	genesis := new(Genesis).MustCommit(db)
 
 	shared, _ := GenerateChain(params.TestChainConfig, genesis, engine, db, 64, func(i int, b *BlockGen) { b.SetCoinbase(common.Address{1}) })
@@ -1301,7 +1301,7 @@ func TestLargeReorgTrieGC(t *testing.T) {
 	competitor, _ := GenerateChain(params.TestChainConfig, shared[len(shared)-1], engine, db, 2*triesInMemory+1, func(i int, b *BlockGen) { b.SetCoinbase(common.Address{3}) })
 
 	// Import the shared chain and the original canonical one
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	new(Genesis).MustCommit(diskdb)
 
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{})
@@ -1361,7 +1361,7 @@ func benchmarkLargeNumberOfValueToNonexisting(b *testing.B, numTxs, numBlocks in
 	)
 	// Generate the original common chain segment and the two competing forks
 	engine := ethash.NewFaker()
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	genesis := gspec.MustCommit(db)
 
 	blockGenerator := func(i int, block *BlockGen) {
@@ -1383,7 +1383,7 @@ func benchmarkLargeNumberOfValueToNonexisting(b *testing.B, numTxs, numBlocks in
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		// Import the shared chain and the original canonical one
-		diskdb, _ := ethdb.NewMemDatabase()
+		diskdb := ethdb.NewMemDatabase()
 		gspec.MustCommit(diskdb)
 
 		chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{})
diff --git a/core/chain_indexer_test.go b/core/chain_indexer_test.go
index 3205616e8d..550caf5567 100644
--- a/core/chain_indexer_test.go
+++ b/core/chain_indexer_test.go
@@ -48,7 +48,7 @@ func TestChainIndexerWithChildren(t *testing.T) {
 // multiple backends. The section size and required confirmation count parameters
 // are randomized.
 func testChainIndexer(t *testing.T, count int) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	defer db.Close()
 
 	// Create a chain of indexers and ensure they all report empty
diff --git a/core/chain_makers.go b/core/chain_makers.go
index 31c9e3fb77..fcba90bb87 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -256,11 +256,12 @@ func makeHeader(chain consensus.ChainReader, parent *types.Block, state *state.S
 // chain. Depending on the full flag, if creates either a full block chain or a
 // header only chain.
 func newCanonical(engine consensus.Engine, n int, full bool) (ethdb.Database, *BlockChain, error) {
-	// Initialize a fresh chain with only a genesis block
-	gspec := new(Genesis)
-	db, _ := ethdb.NewMemDatabase()
-	genesis := gspec.MustCommit(db)
+	var (
+		db      = ethdb.NewMemDatabase()
+		genesis = new(Genesis).MustCommit(db)
+	)
 
+	// Initialize a fresh chain with only a genesis block
 	blockchain, _ := NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{})
 	// Create and inject the requested chain
 	if n == 0 {
diff --git a/core/chain_makers_test.go b/core/chain_makers_test.go
index 93be43ddce..5015d1f48e 100644
--- a/core/chain_makers_test.go
+++ b/core/chain_makers_test.go
@@ -36,7 +36,7 @@ func ExampleGenerateChain() {
 		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
 		addr2   = crypto.PubkeyToAddress(key2.PublicKey)
 		addr3   = crypto.PubkeyToAddress(key3.PublicKey)
-		db, _   = ethdb.NewMemDatabase()
+		db      = ethdb.NewMemDatabase()
 	)
 
 	// Ensure that key1 has some funds in the genesis block.
diff --git a/core/dao_test.go b/core/dao_test.go
index e0a3e3ff37..284b1d98bd 100644
--- a/core/dao_test.go
+++ b/core/dao_test.go
@@ -32,13 +32,13 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	forkBlock := big.NewInt(32)
 
 	// Generate a common prefix for both pro-forkers and non-forkers
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	gspec := new(Genesis)
 	genesis := gspec.MustCommit(db)
 	prefix, _ := GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, int(forkBlock.Int64()-1), func(i int, gen *BlockGen) {})
 
 	// Create the concurrent, conflicting two nodes
-	proDb, _ := ethdb.NewMemDatabase()
+	proDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(proDb)
 
 	proConf := *params.TestChainConfig
@@ -48,7 +48,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	proBc, _ := NewBlockChain(proDb, nil, &proConf, ethash.NewFaker(), vm.Config{})
 	defer proBc.Stop()
 
-	conDb, _ := ethdb.NewMemDatabase()
+	conDb := ethdb.NewMemDatabase()
 	gspec.MustCommit(conDb)
 
 	conConf := *params.TestChainConfig
@@ -67,7 +67,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Try to expand both pro-fork and non-fork chains iteratively with other camp's blocks
 	for i := int64(0); i < params.DAOForkExtraRange.Int64(); i++ {
 		// Create a pro-fork block, and try to feed into the no-fork chain
-		db, _ = ethdb.NewMemDatabase()
+		db = ethdb.NewMemDatabase()
 		gspec.MustCommit(db)
 		bc, _ := NewBlockChain(db, nil, &conConf, ethash.NewFaker(), vm.Config{})
 		defer bc.Stop()
@@ -92,7 +92,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 			t.Fatalf("contra-fork chain didn't accepted no-fork block: %v", err)
 		}
 		// Create a no-fork block, and try to feed into the pro-fork chain
-		db, _ = ethdb.NewMemDatabase()
+		db = ethdb.NewMemDatabase()
 		gspec.MustCommit(db)
 		bc, _ = NewBlockChain(db, nil, &proConf, ethash.NewFaker(), vm.Config{})
 		defer bc.Stop()
@@ -118,7 +118,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		}
 	}
 	// Verify that contra-forkers accept pro-fork extra-datas after forking finishes
-	db, _ = ethdb.NewMemDatabase()
+	db = ethdb.NewMemDatabase()
 	gspec.MustCommit(db)
 	bc, _ := NewBlockChain(db, nil, &conConf, ethash.NewFaker(), vm.Config{})
 	defer bc.Stop()
@@ -138,7 +138,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		t.Fatalf("contra-fork chain didn't accept pro-fork block post-fork: %v", err)
 	}
 	// Verify that pro-forkers accept contra-fork extra-datas after forking finishes
-	db, _ = ethdb.NewMemDatabase()
+	db = ethdb.NewMemDatabase()
 	gspec.MustCommit(db)
 	bc, _ = NewBlockChain(db, nil, &proConf, ethash.NewFaker(), vm.Config{})
 	defer bc.Stop()
diff --git a/core/genesis.go b/core/genesis.go
index c0a636ab2d..9190e2ba22 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -222,7 +222,7 @@ func (g *Genesis) configOrDefault(ghash common.Hash) *params.ChainConfig {
 // to the given database (or discards it if nil).
 func (g *Genesis) ToBlock(db ethdb.Database) *types.Block {
 	if db == nil {
-		db, _ = ethdb.NewMemDatabase()
+		db = ethdb.NewMemDatabase()
 	}
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
 	for addr, account := range g.Alloc {
diff --git a/core/genesis_test.go b/core/genesis_test.go
index 613434e208..2d7f94f8f8 100644
--- a/core/genesis_test.go
+++ b/core/genesis_test.go
@@ -141,7 +141,7 @@ func TestSetupGenesis(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		db, _ := ethdb.NewMemDatabase()
+		db := ethdb.NewMemDatabase()
 		config, hash, err := test.fn(db)
 		// Check the return values.
 		if !reflect.DeepEqual(err, test.wantErr) {
diff --git a/core/helper_test.go b/core/helper_test.go
index 698a2924cb..051384d854 100644
--- a/core/helper_test.go
+++ b/core/helper_test.go
@@ -18,7 +18,6 @@ package core
 
 import (
 	"container/list"
-	"fmt"
 
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethdb"
@@ -77,18 +76,11 @@ func (tm *TestManager) Db() ethdb.Database {
 }
 
 func NewTestManager() *TestManager {
-	db, err := ethdb.NewMemDatabase()
-	if err != nil {
-		fmt.Println("Could not create mem-db, failing")
-		return nil
-	}
-
 	testManager := &TestManager{}
 	testManager.eventMux = new(event.TypeMux)
-	testManager.db = db
+	testManager.db = ethdb.NewMemDatabase()
 	// testManager.txPool = NewTxPool(testManager)
 	// testManager.blockChain = NewBlockChain(testManager)
 	// testManager.stateManager = NewStateManager(testManager)
-
 	return testManager
 }
diff --git a/core/rawdb/accessors_chain_test.go b/core/rawdb/accessors_chain_test.go
index 84c9c9aeb2..9ddae6e2b5 100644
--- a/core/rawdb/accessors_chain_test.go
+++ b/core/rawdb/accessors_chain_test.go
@@ -30,7 +30,7 @@ import (
 
 // Tests block header storage and retrieval operations.
 func TestHeaderStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	// Create a test header to move around the database and make sure it's really new
 	header := &types.Header{Number: big.NewInt(42), Extra: []byte("test header")}
@@ -63,7 +63,7 @@ func TestHeaderStorage(t *testing.T) {
 
 // Tests block body storage and retrieval operations.
 func TestBodyStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	// Create a test body to move around the database and make sure it's really new
 	body := &types.Body{Uncles: []*types.Header{{Extra: []byte("test header")}}}
@@ -101,7 +101,7 @@ func TestBodyStorage(t *testing.T) {
 
 // Tests block storage and retrieval operations.
 func TestBlockStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	// Create a test block to move around the database and make sure it's really new
 	block := types.NewBlockWithHeader(&types.Header{
@@ -151,7 +151,7 @@ func TestBlockStorage(t *testing.T) {
 
 // Tests that partial block contents don't get reassembled into full blocks.
 func TestPartialBlockStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	block := types.NewBlockWithHeader(&types.Header{
 		Extra:       []byte("test block"),
 		UncleHash:   types.EmptyUncleHash,
@@ -185,7 +185,7 @@ func TestPartialBlockStorage(t *testing.T) {
 
 // Tests block total difficulty storage and retrieval operations.
 func TestTdStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	// Create a test TD to move around the database and make sure it's really new
 	hash, td := common.Hash{}, big.NewInt(314)
@@ -208,7 +208,7 @@ func TestTdStorage(t *testing.T) {
 
 // Tests that canonical numbers can be mapped to hashes and retrieved.
 func TestCanonicalMappingStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	// Create a test canonical number and assinged hash to move around
 	hash, number := common.Hash{0: 0xff}, uint64(314)
@@ -231,7 +231,7 @@ func TestCanonicalMappingStorage(t *testing.T) {
 
 // Tests that head headers and head blocks can be assigned, individually.
 func TestHeadStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	blockHead := types.NewBlockWithHeader(&types.Header{Extra: []byte("test block header")})
 	blockFull := types.NewBlockWithHeader(&types.Header{Extra: []byte("test block full")})
@@ -266,7 +266,7 @@ func TestHeadStorage(t *testing.T) {
 
 // Tests that receipts associated with a single block can be stored and retrieved.
 func TestBlockReceiptStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	receipt1 := &types.Receipt{
 		Status:            types.ReceiptStatusFailed,
diff --git a/core/rawdb/accessors_indexes_test.go b/core/rawdb/accessors_indexes_test.go
index d9c1291634..d9c10e1490 100644
--- a/core/rawdb/accessors_indexes_test.go
+++ b/core/rawdb/accessors_indexes_test.go
@@ -27,7 +27,7 @@ import (
 
 // Tests that positional lookup metadata can be stored and retrieved.
 func TestLookupStorage(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 
 	tx1 := types.NewTransaction(1, common.BytesToAddress([]byte{0x11}), big.NewInt(111), 1111, big.NewInt(11111), []byte{0x11, 0x11, 0x11})
 	tx2 := types.NewTransaction(2, common.BytesToAddress([]byte{0x22}), big.NewInt(222), 2222, big.NewInt(22222), []byte{0x22, 0x22, 0x22})
diff --git a/core/state/managed_state_test.go b/core/state/managed_state_test.go
index 1cfdd3a890..3d9c4e8676 100644
--- a/core/state/managed_state_test.go
+++ b/core/state/managed_state_test.go
@@ -26,8 +26,7 @@ import (
 var addr = common.BytesToAddress([]byte("test"))
 
 func create() (*ManagedState, *account) {
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := New(common.Hash{}, NewDatabase(db))
+	statedb, _ := New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
 	ms := ManageState(statedb)
 	ms.StateDB.SetNonce(addr, 100)
 	ms.accounts[addr] = newAccount(ms.StateDB.getStateObject(addr))
diff --git a/core/state/state_test.go b/core/state/state_test.go
index 6d42d63d82..12778f6f12 100644
--- a/core/state/state_test.go
+++ b/core/state/state_test.go
@@ -87,7 +87,7 @@ func (s *StateSuite) TestDump(c *checker.C) {
 }
 
 func (s *StateSuite) SetUpTest(c *checker.C) {
-	s.db, _ = ethdb.NewMemDatabase()
+	s.db = ethdb.NewMemDatabase()
 	s.state, _ = New(common.Hash{}, NewDatabase(s.db))
 }
 
@@ -133,8 +133,7 @@ func (s *StateSuite) TestSnapshotEmpty(c *checker.C) {
 // use testing instead of checker because checker does not support
 // printing/logging in tests (-check.vv does not work)
 func TestSnapshot2(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
-	state, _ := New(common.Hash{}, NewDatabase(db))
+	state, _ := New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
 
 	stateobjaddr0 := toAddr([]byte("so0"))
 	stateobjaddr1 := toAddr([]byte("so1"))
diff --git a/core/state/statedb_test.go b/core/state/statedb_test.go
index 420ca745cc..e2b349de86 100644
--- a/core/state/statedb_test.go
+++ b/core/state/statedb_test.go
@@ -39,7 +39,7 @@ import (
 // actually committing the state.
 func TestUpdateLeaks(t *testing.T) {
 	// Create an empty state database
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	state, _ := New(common.Hash{}, NewDatabase(db))
 
 	// Update it with some accounts
@@ -66,8 +66,8 @@ func TestUpdateLeaks(t *testing.T) {
 // only the one right before the commit.
 func TestIntermediateLeaks(t *testing.T) {
 	// Create two state databases, one transitioning to the final state, the other final from the beginning
-	transDb, _ := ethdb.NewMemDatabase()
-	finalDb, _ := ethdb.NewMemDatabase()
+	transDb := ethdb.NewMemDatabase()
+	finalDb := ethdb.NewMemDatabase()
 	transState, _ := New(common.Hash{}, NewDatabase(transDb))
 	finalState, _ := New(common.Hash{}, NewDatabase(finalDb))
 
@@ -122,8 +122,7 @@ func TestIntermediateLeaks(t *testing.T) {
 // https://github.com/ethereum/go-ethereum/pull/15549.
 func TestCopy(t *testing.T) {
 	// Create a random state test to copy and modify "independently"
-	db, _ := ethdb.NewMemDatabase()
-	orig, _ := New(common.Hash{}, NewDatabase(db))
+	orig, _ := New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
 
 	for i := byte(0); i < 255; i++ {
 		obj := orig.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
@@ -334,8 +333,7 @@ func (test *snapshotTest) String() string {
 func (test *snapshotTest) run() bool {
 	// Run all actions and create snapshots.
 	var (
-		db, _        = ethdb.NewMemDatabase()
-		state, _     = New(common.Hash{}, NewDatabase(db))
+		state, _     = New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
 		snapshotRevs = make([]int, len(test.snapshots))
 		sindex       = 0
 	)
@@ -426,8 +424,7 @@ func (s *StateSuite) TestTouchDelete(c *check.C) {
 // TestCopyOfCopy tests that modified objects are carried over to the copy, and the copy of the copy.
 // See https://github.com/ethereum/go-ethereum/pull/15225#issuecomment-380191512
 func TestCopyOfCopy(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
-	sdb, _ := New(common.Hash{}, NewDatabase(db))
+	sdb, _ := New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
 	addr := common.HexToAddress("aaaa")
 	sdb.SetBalance(addr, big.NewInt(42))
 
diff --git a/core/state/sync_test.go b/core/state/sync_test.go
index 8f14a44e7a..3177401608 100644
--- a/core/state/sync_test.go
+++ b/core/state/sync_test.go
@@ -38,8 +38,7 @@ type testAccount struct {
 // makeTestState create a sample test state to test node-wise reconstruction.
 func makeTestState() (Database, common.Hash, []*testAccount) {
 	// Create an empty state
-	diskdb, _ := ethdb.NewMemDatabase()
-	db := NewDatabase(diskdb)
+	db := NewDatabase(ethdb.NewMemDatabase())
 	state, _ := New(common.Hash{}, db)
 
 	// Fill it with some arbitrary data
@@ -125,8 +124,7 @@ func checkStateConsistency(db ethdb.Database, root common.Hash) error {
 // Tests that an empty state is not scheduled for syncing.
 func TestEmptyStateSync(t *testing.T) {
 	empty := common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")
-	db, _ := ethdb.NewMemDatabase()
-	if req := NewStateSync(empty, db).Missing(1); len(req) != 0 {
+	if req := NewStateSync(empty, ethdb.NewMemDatabase()).Missing(1); len(req) != 0 {
 		t.Errorf("content requested for empty state: %v", req)
 	}
 }
@@ -141,7 +139,7 @@ func testIterativeStateSync(t *testing.T, batch int) {
 	srcDb, srcRoot, srcAccounts := makeTestState()
 
 	// Create a destination state and sync with the scheduler
-	dstDb, _ := ethdb.NewMemDatabase()
+	dstDb := ethdb.NewMemDatabase()
 	sched := NewStateSync(srcRoot, dstDb)
 
 	queue := append([]common.Hash{}, sched.Missing(batch)...)
@@ -173,7 +171,7 @@ func TestIterativeDelayedStateSync(t *testing.T) {
 	srcDb, srcRoot, srcAccounts := makeTestState()
 
 	// Create a destination state and sync with the scheduler
-	dstDb, _ := ethdb.NewMemDatabase()
+	dstDb := ethdb.NewMemDatabase()
 	sched := NewStateSync(srcRoot, dstDb)
 
 	queue := append([]common.Hash{}, sched.Missing(0)...)
@@ -210,7 +208,7 @@ func testIterativeRandomStateSync(t *testing.T, batch int) {
 	srcDb, srcRoot, srcAccounts := makeTestState()
 
 	// Create a destination state and sync with the scheduler
-	dstDb, _ := ethdb.NewMemDatabase()
+	dstDb := ethdb.NewMemDatabase()
 	sched := NewStateSync(srcRoot, dstDb)
 
 	queue := make(map[common.Hash]struct{})
@@ -250,7 +248,7 @@ func TestIterativeRandomDelayedStateSync(t *testing.T) {
 	srcDb, srcRoot, srcAccounts := makeTestState()
 
 	// Create a destination state and sync with the scheduler
-	dstDb, _ := ethdb.NewMemDatabase()
+	dstDb := ethdb.NewMemDatabase()
 	sched := NewStateSync(srcRoot, dstDb)
 
 	queue := make(map[common.Hash]struct{})
@@ -297,7 +295,7 @@ func TestIncompleteStateSync(t *testing.T) {
 	checkTrieConsistency(srcDb.TrieDB().DiskDB().(ethdb.Database), srcRoot)
 
 	// Create a destination state and sync with the scheduler
-	dstDb, _ := ethdb.NewMemDatabase()
+	dstDb := ethdb.NewMemDatabase()
 	sched := NewStateSync(srcRoot, dstDb)
 
 	added := []common.Hash{}
diff --git a/core/tx_pool_test.go b/core/tx_pool_test.go
index f0f86415d4..e7f52075e5 100644
--- a/core/tx_pool_test.go
+++ b/core/tx_pool_test.go
@@ -78,8 +78,7 @@ func pricedTransaction(nonce uint64, gaslimit uint64, gasprice *big.Int, key *ec
 }
 
 func setupTxPool() (*TxPool, *ecdsa.PrivateKey) {
-	diskdb, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(diskdb))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	key, _ := crypto.GenerateKey()
@@ -158,8 +157,7 @@ func (c *testChain) State() (*state.StateDB, error) {
 	// a state change between those fetches.
 	stdb := c.statedb
 	if *c.trigger {
-		db, _ := ethdb.NewMemDatabase()
-		c.statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		c.statedb, _ = state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 		// simulate that the new head block included tx0 and tx1
 		c.statedb.SetNonce(c.address, 2)
 		c.statedb.SetBalance(c.address, new(big.Int).SetUint64(params.Ether))
@@ -175,10 +173,9 @@ func TestStateChangeDuringTransactionPoolReset(t *testing.T) {
 	t.Parallel()
 
 	var (
-		db, _      = ethdb.NewMemDatabase()
 		key, _     = crypto.GenerateKey()
 		address    = crypto.PubkeyToAddress(key.PublicKey)
-		statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		statedb, _ = state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 		trigger    = false
 	)
 
@@ -332,8 +329,7 @@ func TestTransactionChainFork(t *testing.T) {
 
 	addr := crypto.PubkeyToAddress(key.PublicKey)
 	resetState := func() {
-		db, _ := ethdb.NewMemDatabase()
-		statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+		statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 		statedb.AddBalance(addr, big.NewInt(100000000000000))
 
 		pool.chain = &testBlockChain{statedb, 1000000, new(event.Feed)}
@@ -362,8 +358,7 @@ func TestTransactionDoubleNonce(t *testing.T) {
 
 	addr := crypto.PubkeyToAddress(key.PublicKey)
 	resetState := func() {
-		db, _ := ethdb.NewMemDatabase()
-		statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+		statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 		statedb.AddBalance(addr, big.NewInt(100000000000000))
 
 		pool.chain = &testBlockChain{statedb, 1000000, new(event.Feed)}
@@ -553,8 +548,7 @@ func TestTransactionPostponing(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the postponing with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
@@ -769,8 +763,7 @@ func testTransactionQueueGlobalLimiting(t *testing.T, nolocals bool) {
 	t.Parallel()
 
 	// Create the pool to test the limit enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -858,8 +851,7 @@ func testTransactionQueueTimeLimiting(t *testing.T, nolocals bool) {
 	evictionInterval = time.Second
 
 	// Create the pool to test the non-expiration enforcement
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1013,8 +1005,7 @@ func TestTransactionPendingGlobalLimiting(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the limit enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1060,8 +1051,7 @@ func TestTransactionCapClearsFromAll(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the limit enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1095,8 +1085,7 @@ func TestTransactionPendingMinimumAllowance(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the limit enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1144,8 +1133,7 @@ func TestTransactionPoolRepricing(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the pricing enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
@@ -1266,8 +1254,7 @@ func TestTransactionPoolRepricingKeepsLocals(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the pricing enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
@@ -1329,8 +1316,7 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the pricing enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1436,8 +1422,7 @@ func TestTransactionPoolStableUnderpricing(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the pricing enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1503,8 +1488,7 @@ func TestTransactionReplacement(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the pricing enforcement with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
@@ -1598,8 +1582,7 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	os.Remove(journal)
 
 	// Create the original pool to inject transaction into the journal
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
@@ -1697,8 +1680,7 @@ func TestTransactionStatusCheck(t *testing.T) {
 	t.Parallel()
 
 	// Create the pool to test the status retrievals with
-	db, _ := ethdb.NewMemDatabase()
-	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
diff --git a/core/vm/runtime/runtime.go b/core/vm/runtime/runtime.go
index 5ac5464064..c8c5d34d9d 100644
--- a/core/vm/runtime/runtime.go
+++ b/core/vm/runtime/runtime.go
@@ -99,8 +99,7 @@ func Execute(code, input []byte, cfg *Config) ([]byte, *state.StateDB, error) {
 	setDefaults(cfg)
 
 	if cfg.State == nil {
-		db, _ := ethdb.NewMemDatabase()
-		cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	}
 	var (
 		address = common.BytesToAddress([]byte("contract"))
@@ -130,8 +129,7 @@ func Create(input []byte, cfg *Config) ([]byte, common.Address, uint64, error) {
 	setDefaults(cfg)
 
 	if cfg.State == nil {
-		db, _ := ethdb.NewMemDatabase()
-		cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	}
 	var (
 		vmenv  = NewEnv(cfg)
diff --git a/core/vm/runtime/runtime_test.go b/core/vm/runtime/runtime_test.go
index 2c4dc50265..ef664bda30 100644
--- a/core/vm/runtime/runtime_test.go
+++ b/core/vm/runtime/runtime_test.go
@@ -94,8 +94,7 @@ func TestExecute(t *testing.T) {
 }
 
 func TestCall(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
-	state, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	state, _ := state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 	address := common.HexToAddress("0x0a")
 	state.SetCode(address, []byte{
 		byte(vm.PUSH1), 10,
diff --git a/crypto/crypto.go b/crypto/crypto.go
index 1c4d5a2e02..76d1ffaf64 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -35,8 +35,8 @@ import (
 )
 
 var (
-	secp256k1_N, _  = new(big.Int).SetString("fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141", 16)
-	secp256k1_halfN = new(big.Int).Div(secp256k1_N, big.NewInt(2))
+	secp256k1N, _  = new(big.Int).SetString("fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141", 16)
+	secp256k1halfN = new(big.Int).Div(secp256k1N, big.NewInt(2))
 )
 
 // Keccak256 calculates and returns the Keccak256 hash of the input data.
@@ -68,7 +68,7 @@ func Keccak512(data ...[]byte) []byte {
 	return d.Sum(nil)
 }
 
-// Creates an ethereum address given the bytes and the nonce
+// CreateAddress creates an ethereum address given the bytes and the nonce
 func CreateAddress(b common.Address, nonce uint64) common.Address {
 	data, _ := rlp.EncodeToBytes([]interface{}{b, nonce})
 	return common.BytesToAddress(Keccak256(data)[12:])
@@ -99,7 +99,7 @@ func toECDSA(d []byte, strict bool) (*ecdsa.PrivateKey, error) {
 	priv.D = new(big.Int).SetBytes(d)
 
 	// The priv.D must < N
-	if priv.D.Cmp(secp256k1_N) >= 0 {
+	if priv.D.Cmp(secp256k1N) >= 0 {
 		return nil, fmt.Errorf("invalid private key, >=N")
 	}
 	// The priv.D must not be zero or negative.
@@ -184,11 +184,11 @@ func ValidateSignatureValues(v byte, r, s *big.Int, homestead bool) bool {
 	}
 	// reject upper range of s values (ECDSA malleability)
 	// see discussion in secp256k1/libsecp256k1/include/secp256k1.h
-	if homestead && s.Cmp(secp256k1_halfN) > 0 {
+	if homestead && s.Cmp(secp256k1halfN) > 0 {
 		return false
 	}
 	// Frontier: allow s to be in full N range
-	return r.Cmp(secp256k1_N) < 0 && s.Cmp(secp256k1_N) < 0 && (v == 0 || v == 1)
+	return r.Cmp(secp256k1N) < 0 && s.Cmp(secp256k1N) < 0 && (v == 0 || v == 1)
 }
 
 func PubkeyToAddress(p ecdsa.PublicKey) common.Address {
diff --git a/crypto/crypto_test.go b/crypto/crypto_test.go
index 8350354623..804de3fe22 100644
--- a/crypto/crypto_test.go
+++ b/crypto/crypto_test.go
@@ -154,7 +154,7 @@ func TestValidateSignatureValues(t *testing.T) {
 	minusOne := big.NewInt(-1)
 	one := common.Big1
 	zero := common.Big0
-	secp256k1nMinus1 := new(big.Int).Sub(secp256k1_N, common.Big1)
+	secp256k1nMinus1 := new(big.Int).Sub(secp256k1N, common.Big1)
 
 	// correct v,r,s
 	check(true, 0, one, one)
@@ -181,9 +181,9 @@ func TestValidateSignatureValues(t *testing.T) {
 	// correct sig with max r,s
 	check(true, 0, secp256k1nMinus1, secp256k1nMinus1)
 	// correct v, combinations of incorrect r,s at upper limit
-	check(false, 0, secp256k1_N, secp256k1nMinus1)
-	check(false, 0, secp256k1nMinus1, secp256k1_N)
-	check(false, 0, secp256k1_N, secp256k1_N)
+	check(false, 0, secp256k1N, secp256k1nMinus1)
+	check(false, 0, secp256k1nMinus1, secp256k1N)
+	check(false, 0, secp256k1N, secp256k1N)
 
 	// current callers ensures r,s cannot be negative, but let's test for that too
 	// as crypto package could be used stand-alone
diff --git a/crypto/secp256k1/curve.go b/crypto/secp256k1/curve.go
index f51be5e353..6fdf2be6a4 100644
--- a/crypto/secp256k1/curve.go
+++ b/crypto/secp256k1/curve.go
@@ -77,7 +77,7 @@ func (BitCurve *BitCurve) Params() *elliptic.CurveParams {
 	}
 }
 
-// IsOnBitCurve returns true if the given (x,y) lies on the BitCurve.
+// IsOnCurve returns true if the given (x,y) lies on the BitCurve.
 func (BitCurve *BitCurve) IsOnCurve(x, y *big.Int) bool {
 	// y² = x³ + b
 	y2 := new(big.Int).Mul(y, y) //y²
diff --git a/crypto/secp256k1/secp256_test.go b/crypto/secp256k1/secp256_test.go
index f6582ecd54..b608bcfcf1 100644
--- a/crypto/secp256k1/secp256_test.go
+++ b/crypto/secp256k1/secp256_test.go
@@ -49,7 +49,7 @@ func randSig() []byte {
 // tests for malleability
 // highest bit of signature ECDSA s value must be 0, in the 33th byte
 func compactSigCheck(t *testing.T, sig []byte) {
-	var b int = int(sig[32])
+	var b = int(sig[32])
 	if b < 0 {
 		t.Errorf("highest bit is negative: %d", b)
 	}
diff --git a/crypto/signature_nocgo.go b/crypto/signature_nocgo.go
index f636b23772..e8fa18ed47 100644
--- a/crypto/signature_nocgo.go
+++ b/crypto/signature_nocgo.go
@@ -88,7 +88,7 @@ func VerifySignature(pubkey, hash, signature []byte) bool {
 		return false
 	}
 	// Reject malleable signatures. libsecp256k1 does this check but btcec doesn't.
-	if sig.S.Cmp(secp256k1_halfN) > 0 {
+	if sig.S.Cmp(secp256k1halfN) > 0 {
 		return false
 	}
 	return sig.Verify(hash, key)
diff --git a/eth/api_backend.go b/eth/api_backend.go
index 532cd5c334..4ace9b5945 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -37,26 +37,26 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 )
 
-// EthApiBackend implements ethapi.Backend for full nodes
-type EthApiBackend struct {
+// EthAPIBackend implements ethapi.Backend for full nodes
+type EthAPIBackend struct {
 	eth *Ethereum
 	gpo *gasprice.Oracle
 }
 
-func (b *EthApiBackend) ChainConfig() *params.ChainConfig {
+func (b *EthAPIBackend) ChainConfig() *params.ChainConfig {
 	return b.eth.chainConfig
 }
 
-func (b *EthApiBackend) CurrentBlock() *types.Block {
+func (b *EthAPIBackend) CurrentBlock() *types.Block {
 	return b.eth.blockchain.CurrentBlock()
 }
 
-func (b *EthApiBackend) SetHead(number uint64) {
+func (b *EthAPIBackend) SetHead(number uint64) {
 	b.eth.protocolManager.downloader.Cancel()
 	b.eth.blockchain.SetHead(number)
 }
 
-func (b *EthApiBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error) {
+func (b *EthAPIBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error) {
 	// Pending block is only known by the miner
 	if blockNr == rpc.PendingBlockNumber {
 		block := b.eth.miner.PendingBlock()
@@ -69,7 +69,7 @@ func (b *EthApiBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNum
 	return b.eth.blockchain.GetHeaderByNumber(uint64(blockNr)), nil
 }
 
-func (b *EthApiBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Block, error) {
+func (b *EthAPIBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Block, error) {
 	// Pending block is only known by the miner
 	if blockNr == rpc.PendingBlockNumber {
 		block := b.eth.miner.PendingBlock()
@@ -82,7 +82,7 @@ func (b *EthApiBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumb
 	return b.eth.blockchain.GetBlockByNumber(uint64(blockNr)), nil
 }
 
-func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
+func (b *EthAPIBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
 	// Pending state is only known by the miner
 	if blockNr == rpc.PendingBlockNumber {
 		block, state := b.eth.miner.Pending()
@@ -97,18 +97,18 @@ func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.
 	return stateDb, header, err
 }
 
-func (b *EthApiBackend) GetBlock(ctx context.Context, hash common.Hash) (*types.Block, error) {
+func (b *EthAPIBackend) GetBlock(ctx context.Context, hash common.Hash) (*types.Block, error) {
 	return b.eth.blockchain.GetBlockByHash(hash), nil
 }
 
-func (b *EthApiBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
+func (b *EthAPIBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
 	if number := rawdb.ReadHeaderNumber(b.eth.chainDb, hash); number != nil {
 		return rawdb.ReadReceipts(b.eth.chainDb, hash, *number), nil
 	}
 	return nil, nil
 }
 
-func (b *EthApiBackend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
+func (b *EthAPIBackend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
 	number := rawdb.ReadHeaderNumber(b.eth.chainDb, hash)
 	if number == nil {
 		return nil, nil
@@ -124,11 +124,11 @@ func (b *EthApiBackend) GetLogs(ctx context.Context, hash common.Hash) ([][]*typ
 	return logs, nil
 }
 
-func (b *EthApiBackend) GetTd(blockHash common.Hash) *big.Int {
+func (b *EthAPIBackend) GetTd(blockHash common.Hash) *big.Int {
 	return b.eth.blockchain.GetTdByHash(blockHash)
 }
 
-func (b *EthApiBackend) GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header, vmCfg vm.Config) (*vm.EVM, func() error, error) {
+func (b *EthAPIBackend) GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header, vmCfg vm.Config) (*vm.EVM, func() error, error) {
 	state.SetBalance(msg.From(), math.MaxBig256)
 	vmError := func() error { return nil }
 
@@ -136,31 +136,31 @@ func (b *EthApiBackend) GetEVM(ctx context.Context, msg core.Message, state *sta
 	return vm.NewEVM(context, state, b.eth.chainConfig, vmCfg), vmError, nil
 }
 
-func (b *EthApiBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
+func (b *EthAPIBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
 	return b.eth.BlockChain().SubscribeRemovedLogsEvent(ch)
 }
 
-func (b *EthApiBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
+func (b *EthAPIBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
 	return b.eth.BlockChain().SubscribeChainEvent(ch)
 }
 
-func (b *EthApiBackend) SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription {
+func (b *EthAPIBackend) SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription {
 	return b.eth.BlockChain().SubscribeChainHeadEvent(ch)
 }
 
-func (b *EthApiBackend) SubscribeChainSideEvent(ch chan<- core.ChainSideEvent) event.Subscription {
+func (b *EthAPIBackend) SubscribeChainSideEvent(ch chan<- core.ChainSideEvent) event.Subscription {
 	return b.eth.BlockChain().SubscribeChainSideEvent(ch)
 }
 
-func (b *EthApiBackend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
+func (b *EthAPIBackend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
 	return b.eth.BlockChain().SubscribeLogsEvent(ch)
 }
 
-func (b *EthApiBackend) SendTx(ctx context.Context, signedTx *types.Transaction) error {
+func (b *EthAPIBackend) SendTx(ctx context.Context, signedTx *types.Transaction) error {
 	return b.eth.txPool.AddLocal(signedTx)
 }
 
-func (b *EthApiBackend) GetPoolTransactions() (types.Transactions, error) {
+func (b *EthAPIBackend) GetPoolTransactions() (types.Transactions, error) {
 	pending, err := b.eth.txPool.Pending()
 	if err != nil {
 		return nil, err
@@ -172,56 +172,56 @@ func (b *EthApiBackend) GetPoolTransactions() (types.Transactions, error) {
 	return txs, nil
 }
 
-func (b *EthApiBackend) GetPoolTransaction(hash common.Hash) *types.Transaction {
+func (b *EthAPIBackend) GetPoolTransaction(hash common.Hash) *types.Transaction {
 	return b.eth.txPool.Get(hash)
 }
 
-func (b *EthApiBackend) GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error) {
+func (b *EthAPIBackend) GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error) {
 	return b.eth.txPool.State().GetNonce(addr), nil
 }
 
-func (b *EthApiBackend) Stats() (pending int, queued int) {
+func (b *EthAPIBackend) Stats() (pending int, queued int) {
 	return b.eth.txPool.Stats()
 }
 
-func (b *EthApiBackend) TxPoolContent() (map[common.Address]types.Transactions, map[common.Address]types.Transactions) {
+func (b *EthAPIBackend) TxPoolContent() (map[common.Address]types.Transactions, map[common.Address]types.Transactions) {
 	return b.eth.TxPool().Content()
 }
 
-func (b *EthApiBackend) SubscribeTxPreEvent(ch chan<- core.TxPreEvent) event.Subscription {
+func (b *EthAPIBackend) SubscribeTxPreEvent(ch chan<- core.TxPreEvent) event.Subscription {
 	return b.eth.TxPool().SubscribeTxPreEvent(ch)
 }
 
-func (b *EthApiBackend) Downloader() *downloader.Downloader {
+func (b *EthAPIBackend) Downloader() *downloader.Downloader {
 	return b.eth.Downloader()
 }
 
-func (b *EthApiBackend) ProtocolVersion() int {
+func (b *EthAPIBackend) ProtocolVersion() int {
 	return b.eth.EthVersion()
 }
 
-func (b *EthApiBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
+func (b *EthAPIBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
 	return b.gpo.SuggestPrice(ctx)
 }
 
-func (b *EthApiBackend) ChainDb() ethdb.Database {
+func (b *EthAPIBackend) ChainDb() ethdb.Database {
 	return b.eth.ChainDb()
 }
 
-func (b *EthApiBackend) EventMux() *event.TypeMux {
+func (b *EthAPIBackend) EventMux() *event.TypeMux {
 	return b.eth.EventMux()
 }
 
-func (b *EthApiBackend) AccountManager() *accounts.Manager {
+func (b *EthAPIBackend) AccountManager() *accounts.Manager {
 	return b.eth.AccountManager()
 }
 
-func (b *EthApiBackend) BloomStatus() (uint64, uint64) {
+func (b *EthAPIBackend) BloomStatus() (uint64, uint64) {
 	sections, _, _ := b.eth.bloomIndexer.Sections()
 	return params.BloomBitsBlocks, sections
 }
 
-func (b *EthApiBackend) ServiceFilter(ctx context.Context, session *bloombits.MatcherSession) {
+func (b *EthAPIBackend) ServiceFilter(ctx context.Context, session *bloombits.MatcherSession) {
 	for i := 0; i < bloomFilterThreads; i++ {
 		go session.Multiplex(bloomRetrievalBatch, bloomRetrievalWait, b.eth.bloomRequests)
 	}
diff --git a/eth/api_test.go b/eth/api_test.go
index 900a82bb6a..47b062a40c 100644
--- a/eth/api_test.go
+++ b/eth/api_test.go
@@ -31,8 +31,7 @@ var dumper = spew.ConfigState{Indent: "    "}
 func TestStorageRangeAt(t *testing.T) {
 	// Create a state where account 0x010000... has a few storage entries.
 	var (
-		db, _    = ethdb.NewMemDatabase()
-		state, _ = state.New(common.Hash{}, state.NewDatabase(db))
+		state, _ = state.New(common.Hash{}, state.NewDatabase(ethdb.NewMemDatabase()))
 		addr     = common.Address{0x01}
 		keys     = []common.Hash{ // hashes of Keys of storage
 			common.HexToHash("340dd630ad21bf010b4e676dbfa9ba9a02175262d1fa356232cfde6cb5b47ef2"),
diff --git a/eth/backend.go b/eth/backend.go
index e4c5fef3e4..ea70e3826c 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -82,7 +82,7 @@ type Ethereum struct {
 	bloomRequests chan chan *bloombits.Retrieval // Channel receiving bloom data retrieval requests
 	bloomIndexer  *core.ChainIndexer             // Bloom indexer operating during block imports
 
-	ApiBackend *EthApiBackend
+	APIBackend *EthAPIBackend
 
 	miner     *miner.Miner
 	gasPrice  *big.Int
@@ -169,12 +169,12 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 	eth.miner = miner.New(eth, eth.chainConfig, eth.EventMux(), eth.engine)
 	eth.miner.SetExtra(makeExtraData(config.ExtraData))
 
-	eth.ApiBackend = &EthApiBackend{eth, nil}
+	eth.APIBackend = &EthAPIBackend{eth, nil}
 	gpoParams := config.GPO
 	if gpoParams.Default == nil {
 		gpoParams.Default = config.GasPrice
 	}
-	eth.ApiBackend.gpo = gasprice.NewOracle(eth.ApiBackend, gpoParams)
+	eth.APIBackend.gpo = gasprice.NewOracle(eth.APIBackend, gpoParams)
 
 	return eth, nil
 }
@@ -242,7 +242,7 @@ func CreateConsensusEngine(ctx *node.ServiceContext, config *ethash.Config, chai
 // APIs returns the collection of RPC services the ethereum package offers.
 // NOTE, some of these services probably need to be moved to somewhere else.
 func (s *Ethereum) APIs() []rpc.API {
-	apis := ethapi.GetAPIs(s.ApiBackend)
+	apis := ethapi.GetAPIs(s.APIBackend)
 
 	// Append any APIs exposed explicitly by the consensus engine
 	apis = append(apis, s.engine.APIs(s.BlockChain())...)
@@ -272,7 +272,7 @@ func (s *Ethereum) APIs() []rpc.API {
 		}, {
 			Namespace: "eth",
 			Version:   "1.0",
-			Service:   filters.NewPublicFilterAPI(s.ApiBackend, false),
+			Service:   filters.NewPublicFilterAPI(s.APIBackend, false),
 			Public:    true,
 		}, {
 			Namespace: "admin",
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index e85e234c0e..d1a9a8694b 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -75,7 +75,7 @@ type downloadTester struct {
 
 // newTester creates a new downloader test mocker.
 func newTester() *downloadTester {
-	testdb, _ := ethdb.NewMemDatabase()
+	testdb := ethdb.NewMemDatabase()
 	genesis := core.GenesisBlockForTesting(testdb, testAddress, big.NewInt(1000000000))
 
 	tester := &downloadTester{
@@ -93,7 +93,7 @@ func newTester() *downloadTester {
 		peerChainTds:      make(map[string]map[common.Hash]*big.Int),
 		peerMissingStates: make(map[string]map[common.Hash]bool),
 	}
-	tester.stateDb, _ = ethdb.NewMemDatabase()
+	tester.stateDb = ethdb.NewMemDatabase()
 	tester.stateDb.Put(genesis.Root().Bytes(), []byte{0x00})
 
 	tester.downloader = New(FullSync, tester.stateDb, new(event.TypeMux), tester, nil, tester.dropPeer)
diff --git a/eth/fetcher/fetcher_test.go b/eth/fetcher/fetcher_test.go
index 1e536fcacb..3d4f0d1e59 100644
--- a/eth/fetcher/fetcher_test.go
+++ b/eth/fetcher/fetcher_test.go
@@ -34,7 +34,7 @@ import (
 )
 
 var (
-	testdb, _    = ethdb.NewMemDatabase()
+	testdb       = ethdb.NewMemDatabase()
 	testKey, _   = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 	testAddress  = crypto.PubkeyToAddress(testKey.PublicKey)
 	genesis      = core.GenesisBlockForTesting(testdb, testAddress, big.NewInt(1000000000))
diff --git a/eth/filters/filter_system.go b/eth/filters/filter_system.go
index 6d16f572d0..bb11734a76 100644
--- a/eth/filters/filter_system.go
+++ b/eth/filters/filter_system.go
@@ -31,6 +31,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rpc"
 )
 
@@ -92,8 +93,21 @@ type EventSystem struct {
 	backend   Backend
 	lightMode bool
 	lastHead  *types.Header
-	install   chan *subscription // install filter for event notification
-	uninstall chan *subscription // remove filter for event notification
+
+	// Subscriptions
+	txSub         event.Subscription         // Subscription for new transaction event
+	logsSub       event.Subscription         // Subscription for new log event
+	rmLogsSub     event.Subscription         // Subscription for removed log event
+	chainSub      event.Subscription         // Subscription for new chain event
+	pendingLogSub *event.TypeMuxSubscription // Subscription for pending log event
+
+	// Channels
+	install   chan *subscription         // install filter for event notification
+	uninstall chan *subscription         // remove filter for event notification
+	txCh      chan core.TxPreEvent       // Channel to receive new transaction event
+	logsCh    chan []*types.Log          // Channel to receive new log event
+	rmLogsCh  chan core.RemovedLogsEvent // Channel to receive removed log event
+	chainCh   chan core.ChainEvent       // Channel to receive new chain event
 }
 
 // NewEventSystem creates a new manager that listens for event on the given mux,
@@ -109,10 +123,27 @@ func NewEventSystem(mux *event.TypeMux, backend Backend, lightMode bool) *EventS
 		lightMode: lightMode,
 		install:   make(chan *subscription),
 		uninstall: make(chan *subscription),
+		txCh:      make(chan core.TxPreEvent, txChanSize),
+		logsCh:    make(chan []*types.Log, logsChanSize),
+		rmLogsCh:  make(chan core.RemovedLogsEvent, rmLogsChanSize),
+		chainCh:   make(chan core.ChainEvent, chainEvChanSize),
+	}
+
+	// Subscribe events
+	m.txSub = m.backend.SubscribeTxPreEvent(m.txCh)
+	m.logsSub = m.backend.SubscribeLogsEvent(m.logsCh)
+	m.rmLogsSub = m.backend.SubscribeRemovedLogsEvent(m.rmLogsCh)
+	m.chainSub = m.backend.SubscribeChainEvent(m.chainCh)
+	// TODO(rjl493456442): use feed to subscribe pending log event
+	m.pendingLogSub = m.mux.Subscribe(core.PendingLogsEvent{})
+
+	// Make sure none of the subscriptions are empty
+	if m.txSub == nil || m.logsSub == nil || m.rmLogsSub == nil || m.chainSub == nil ||
+		m.pendingLogSub.Closed() {
+		log.Crit("Subscribe for event system failed")
 	}
 
 	go m.eventLoop()
-
 	return m
 }
 
@@ -412,52 +443,37 @@ func (es *EventSystem) lightFilterLogs(header *types.Header, addresses []common.
 
 // eventLoop (un)installs filters and processes mux events.
 func (es *EventSystem) eventLoop() {
-	var (
-		index = make(filterIndex)
-		sub   = es.mux.Subscribe(core.PendingLogsEvent{})
-		// Subscribe TxPreEvent form txpool
-		txCh  = make(chan core.TxPreEvent, txChanSize)
-		txSub = es.backend.SubscribeTxPreEvent(txCh)
-		// Subscribe RemovedLogsEvent
-		rmLogsCh  = make(chan core.RemovedLogsEvent, rmLogsChanSize)
-		rmLogsSub = es.backend.SubscribeRemovedLogsEvent(rmLogsCh)
-		// Subscribe []*types.Log
-		logsCh  = make(chan []*types.Log, logsChanSize)
-		logsSub = es.backend.SubscribeLogsEvent(logsCh)
-		// Subscribe ChainEvent
-		chainEvCh  = make(chan core.ChainEvent, chainEvChanSize)
-		chainEvSub = es.backend.SubscribeChainEvent(chainEvCh)
-	)
-
-	// Unsubscribe all events
-	defer sub.Unsubscribe()
-	defer txSub.Unsubscribe()
-	defer rmLogsSub.Unsubscribe()
-	defer logsSub.Unsubscribe()
-	defer chainEvSub.Unsubscribe()
+	// Ensure all subscriptions get cleaned up
+	defer func() {
+		es.pendingLogSub.Unsubscribe()
+		es.txSub.Unsubscribe()
+		es.logsSub.Unsubscribe()
+		es.rmLogsSub.Unsubscribe()
+		es.chainSub.Unsubscribe()
+	}()
 
+	index := make(filterIndex)
 	for i := UnknownSubscription; i < LastIndexSubscription; i++ {
 		index[i] = make(map[rpc.ID]*subscription)
 	}
 
 	for {
 		select {
-		case ev, active := <-sub.Chan():
+		// Handle subscribed events
+		case ev := <-es.txCh:
+			es.broadcast(index, ev)
+		case ev := <-es.logsCh:
+			es.broadcast(index, ev)
+		case ev := <-es.rmLogsCh:
+			es.broadcast(index, ev)
+		case ev := <-es.chainCh:
+			es.broadcast(index, ev)
+		case ev, active := <-es.pendingLogSub.Chan():
 			if !active { // system stopped
 				return
 			}
 			es.broadcast(index, ev)
 
-		// Handle subscribed events
-		case ev := <-txCh:
-			es.broadcast(index, ev)
-		case ev := <-rmLogsCh:
-			es.broadcast(index, ev)
-		case ev := <-logsCh:
-			es.broadcast(index, ev)
-		case ev := <-chainEvCh:
-			es.broadcast(index, ev)
-
 		case f := <-es.install:
 			if f.typ == MinedAndPendingLogsSubscription {
 				// the type are logs and pending logs subscriptions
@@ -467,6 +483,7 @@ func (es *EventSystem) eventLoop() {
 				index[f.typ][f.id] = f
 			}
 			close(f.installed)
+
 		case f := <-es.uninstall:
 			if f.typ == MinedAndPendingLogsSubscription {
 				// the type are logs and pending logs subscriptions
@@ -478,13 +495,13 @@ func (es *EventSystem) eventLoop() {
 			close(f.err)
 
 		// System stopped
-		case <-txSub.Err():
+		case <-es.txSub.Err():
 			return
-		case <-rmLogsSub.Err():
+		case <-es.logsSub.Err():
 			return
-		case <-logsSub.Err():
+		case <-es.rmLogsSub.Err():
 			return
-		case <-chainEvSub.Err():
+		case <-es.chainSub.Err():
 			return
 		}
 	}
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index 73819eadc0..b4df24b471 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -153,7 +153,7 @@ func TestBlockSubscription(t *testing.T) {
 
 	var (
 		mux         = new(event.TypeMux)
-		db, _       = ethdb.NewMemDatabase()
+		db          = ethdb.NewMemDatabase()
 		txFeed      = new(event.Feed)
 		rmLogsFeed  = new(event.Feed)
 		logsFeed    = new(event.Feed)
@@ -210,7 +210,7 @@ func TestPendingTxFilter(t *testing.T) {
 
 	var (
 		mux        = new(event.TypeMux)
-		db, _      = ethdb.NewMemDatabase()
+		db         = ethdb.NewMemDatabase()
 		txFeed     = new(event.Feed)
 		rmLogsFeed = new(event.Feed)
 		logsFeed   = new(event.Feed)
@@ -273,7 +273,7 @@ func TestPendingTxFilter(t *testing.T) {
 func TestLogFilterCreation(t *testing.T) {
 	var (
 		mux        = new(event.TypeMux)
-		db, _      = ethdb.NewMemDatabase()
+		db         = ethdb.NewMemDatabase()
 		txFeed     = new(event.Feed)
 		rmLogsFeed = new(event.Feed)
 		logsFeed   = new(event.Feed)
@@ -322,7 +322,7 @@ func TestInvalidLogFilterCreation(t *testing.T) {
 
 	var (
 		mux        = new(event.TypeMux)
-		db, _      = ethdb.NewMemDatabase()
+		db         = ethdb.NewMemDatabase()
 		txFeed     = new(event.Feed)
 		rmLogsFeed = new(event.Feed)
 		logsFeed   = new(event.Feed)
@@ -352,7 +352,7 @@ func TestLogFilter(t *testing.T) {
 
 	var (
 		mux        = new(event.TypeMux)
-		db, _      = ethdb.NewMemDatabase()
+		db         = ethdb.NewMemDatabase()
 		txFeed     = new(event.Feed)
 		rmLogsFeed = new(event.Feed)
 		logsFeed   = new(event.Feed)
@@ -471,7 +471,7 @@ func TestPendingLogsSubscription(t *testing.T) {
 
 	var (
 		mux        = new(event.TypeMux)
-		db, _      = ethdb.NewMemDatabase()
+		db         = ethdb.NewMemDatabase()
 		txFeed     = new(event.Feed)
 		rmLogsFeed = new(event.Feed)
 		logsFeed   = new(event.Feed)
diff --git a/eth/handler_test.go b/eth/handler_test.go
index e336dfa285..fee4114eb6 100644
--- a/eth/handler_test.go
+++ b/eth/handler_test.go
@@ -366,7 +366,7 @@ func testGetNodeData(t *testing.T, protocol int) {
 			t.Errorf("data hash mismatch: have %x, want %x", hash, want)
 		}
 	}
-	statedb, _ := ethdb.NewMemDatabase()
+	statedb := ethdb.NewMemDatabase()
 	for i := 0; i < len(data); i++ {
 		statedb.Put(hashes[i].Bytes(), data[i])
 	}
@@ -468,7 +468,7 @@ func testDAOChallenge(t *testing.T, localForked, remoteForked bool, timeout bool
 	var (
 		evmux         = new(event.TypeMux)
 		pow           = ethash.NewFaker()
-		db, _         = ethdb.NewMemDatabase()
+		db            = ethdb.NewMemDatabase()
 		config        = &params.ChainConfig{DAOForkBlock: big.NewInt(1), DAOForkSupport: localForked}
 		gspec         = &core.Genesis{Config: config}
 		genesis       = gspec.MustCommit(db)
diff --git a/eth/helper_test.go b/eth/helper_test.go
index 2b05cea801..8a0260fc95 100644
--- a/eth/helper_test.go
+++ b/eth/helper_test.go
@@ -53,7 +53,7 @@ func newTestProtocolManager(mode downloader.SyncMode, blocks int, generator func
 	var (
 		evmux  = new(event.TypeMux)
 		engine = ethash.NewFaker()
-		db, _  = ethdb.NewMemDatabase()
+		db     = ethdb.NewMemDatabase()
 		gspec  = &core.Genesis{
 			Config: params.TestChainConfig,
 			Alloc:  core.GenesisAlloc{testBank: {Balance: big.NewInt(1000000)}},
diff --git a/eth/protocol.go b/eth/protocol.go
index cd7db57f23..328d5b9939 100644
--- a/eth/protocol.go
+++ b/eth/protocol.go
@@ -34,13 +34,13 @@ const (
 	eth63 = 63
 )
 
-// Official short name of the protocol used during capability negotiation.
+// ProtocolName is the official short name of the protocol used during capability negotiation.
 var ProtocolName = "eth"
 
-// Supported versions of the eth protocol (first is primary).
+// ProtocolVersions are the upported versions of the eth protocol (first is primary).
 var ProtocolVersions = []uint{eth63, eth62}
 
-// Number of implemented message corresponding to different protocol versions.
+// ProtocolLengths are the number of implemented message corresponding to different protocol versions.
 var ProtocolLengths = []uint64{17, 8}
 
 const ProtocolMaxMsgSize = 10 * 1024 * 1024 // Maximum cap on the size of a protocol message
diff --git a/eth/tracers/tracers_test.go b/eth/tracers/tracers_test.go
index bf8120228f..d25fc459a1 100644
--- a/eth/tracers/tracers_test.go
+++ b/eth/tracers/tracers_test.go
@@ -159,8 +159,7 @@ func TestCallTracer(t *testing.T) {
 				GasLimit:    uint64(test.Context.GasLimit),
 				GasPrice:    tx.GasPrice(),
 			}
-			db, _ := ethdb.NewMemDatabase()
-			statedb := tests.MakePreState(db, test.Genesis.Alloc)
+			statedb := tests.MakePreState(ethdb.NewMemDatabase(), test.Genesis.Alloc)
 
 			// Create the tracer, the EVM environment and run it
 			tracer, err := New("callTracer")
diff --git a/ethdb/database_test.go b/ethdb/database_test.go
index 5e4a3ca34a..2deb50988c 100644
--- a/ethdb/database_test.go
+++ b/ethdb/database_test.go
@@ -53,8 +53,7 @@ func TestLDB_PutGet(t *testing.T) {
 }
 
 func TestMemoryDB_PutGet(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
-	testPutGet(db, t)
+	testPutGet(ethdb.NewMemDatabase(), t)
 }
 
 func testPutGet(db ethdb.Database, t *testing.T) {
@@ -131,8 +130,7 @@ func TestLDB_ParallelPutGet(t *testing.T) {
 }
 
 func TestMemoryDB_ParallelPutGet(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
-	testParallelPutGet(db, t)
+	testParallelPutGet(ethdb.NewMemDatabase(), t)
 }
 
 func testParallelPutGet(db ethdb.Database, t *testing.T) {
diff --git a/ethdb/memory_database.go b/ethdb/memory_database.go
index dd6d3c1965..9b055bf4a1 100644
--- a/ethdb/memory_database.go
+++ b/ethdb/memory_database.go
@@ -37,14 +37,14 @@ type MemDatabase struct {
 func NewMemDatabase() (*MemDatabase, error) {
 	return &MemDatabase{
 		db: make(map[string][]byte),
-	}, nil
+	}
 }
 
 // NewMemDatabaseWithCap inits a mock levelDB instance with a map and sets a maximum size..
 func NewMemDatabaseWithCap(size int) (*MemDatabase, error) {
 	return &MemDatabase{
 		db: make(map[string][]byte, size),
-	}, nil
+	}
 }
 
 // Put sets the value of the key.
diff --git a/ethstats/ethstats.go b/ethstats/ethstats.go
index ae7e252654..a15d846150 100644
--- a/ethstats/ethstats.go
+++ b/ethstats/ethstats.go
@@ -689,7 +689,7 @@ func (s *Service) reportStats(conn *websocket.Conn) error {
 		sync := s.eth.Downloader().Progress()
 		syncing = s.eth.BlockChain().CurrentHeader().Number.Uint64() >= sync.HighestBlock
 
-		price, _ := s.eth.ApiBackend.SuggestPrice(context.Background())
+		price, _ := s.eth.APIBackend.SuggestPrice(context.Background())
 		gasprice = int(price.Uint64())
 	} else {
 		sync := s.les.Downloader().Progress()
diff --git a/event/event.go b/event/event.go
index 20d20d1f57..4232787314 100644
--- a/event/event.go
+++ b/event/event.go
@@ -180,6 +180,12 @@ func (s *TypeMuxSubscription) Unsubscribe() {
 	s.closewait()
 }
 
+func (s *TypeMuxSubscription) Closed() bool {
+	s.closeMu.Lock()
+	defer s.closeMu.Unlock()
+	return s.closed
+}
+
 func (s *TypeMuxSubscription) closewait() {
 	s.closeMu.Lock()
 	defer s.closeMu.Unlock()
diff --git a/internal/build/pgp.go b/internal/build/pgp.go
index 79ab9c06f1..c7d0d23397 100644
--- a/internal/build/pgp.go
+++ b/internal/build/pgp.go
@@ -57,3 +57,15 @@ func PGPSignFile(input string, output string, pgpkey string) error {
 	// Generate the signature and return
 	return openpgp.ArmoredDetachSign(out, keys[0], in, nil)
 }
+
+// PGPKeyID parses an armored key and returns the key ID.
+func PGPKeyID(pgpkey string) (string, error) {
+	keys, err := openpgp.ReadArmoredKeyRing(bytes.NewBufferString(pgpkey))
+	if err != nil {
+		return "", err
+	}
+	if len(keys) != 1 {
+		return "", fmt.Errorf("key count mismatch: have %d, want %d", len(keys), 1)
+	}
+	return keys[0].PrimaryKey.KeyIdString(), nil
+}
diff --git a/les/handler_test.go b/les/handler_test.go
index fa38d1d4f7..31aad3ed45 100644
--- a/les/handler_test.go
+++ b/les/handler_test.go
@@ -51,8 +51,7 @@ func TestGetBlockHeadersLes1(t *testing.T) { testGetBlockHeaders(t, 1) }
 func TestGetBlockHeadersLes2(t *testing.T) { testGetBlockHeaders(t, 2) }
 
 func testGetBlockHeaders(t *testing.T, protocol int) {
-	db, _ := ethdb.NewMemDatabase()
-	pm := newTestProtocolManagerMust(t, false, downloader.MaxHashFetch+15, nil, nil, nil, db)
+	pm := newTestProtocolManagerMust(t, false, downloader.MaxHashFetch+15, nil, nil, nil, ethdb.NewMemDatabase())
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", protocol, pm, true)
 	defer peer.close()
@@ -181,8 +180,7 @@ func TestGetBlockBodiesLes1(t *testing.T) { testGetBlockBodies(t, 1) }
 func TestGetBlockBodiesLes2(t *testing.T) { testGetBlockBodies(t, 2) }
 
 func testGetBlockBodies(t *testing.T, protocol int) {
-	db, _ := ethdb.NewMemDatabase()
-	pm := newTestProtocolManagerMust(t, false, downloader.MaxBlockFetch+15, nil, nil, nil, db)
+	pm := newTestProtocolManagerMust(t, false, downloader.MaxBlockFetch+15, nil, nil, nil, ethdb.NewMemDatabase())
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", protocol, pm, true)
 	defer peer.close()
@@ -259,8 +257,7 @@ func TestGetCodeLes2(t *testing.T) { testGetCode(t, 2) }
 
 func testGetCode(t *testing.T, protocol int) {
 	// Assemble the test environment
-	db, _ := ethdb.NewMemDatabase()
-	pm := newTestProtocolManagerMust(t, false, 4, testChainGen, nil, nil, db)
+	pm := newTestProtocolManagerMust(t, false, 4, testChainGen, nil, nil, ethdb.NewMemDatabase())
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", protocol, pm, true)
 	defer peer.close()
@@ -293,7 +290,7 @@ func TestGetReceiptLes2(t *testing.T) { testGetReceipt(t, 2) }
 
 func testGetReceipt(t *testing.T, protocol int) {
 	// Assemble the test environment
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	pm := newTestProtocolManagerMust(t, false, 4, testChainGen, nil, nil, db)
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", protocol, pm, true)
@@ -321,7 +318,7 @@ func TestGetProofsLes2(t *testing.T) { testGetProofs(t, 2) }
 
 func testGetProofs(t *testing.T, protocol int) {
 	// Assemble the test environment
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	pm := newTestProtocolManagerMust(t, false, 4, testChainGen, nil, nil, db)
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", protocol, pm, true)
@@ -384,7 +381,7 @@ func testGetCHTProofs(t *testing.T, protocol int) {
 		frequency = uint64(light.CHTFrequencyServer)
 	}
 	// Assemble the test environment
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	pm := newTestProtocolManagerMust(t, false, int(frequency)+light.HelperTrieProcessConfirmations, testChainGen, nil, nil, db)
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", protocol, pm, true)
@@ -452,7 +449,7 @@ func testGetCHTProofs(t *testing.T, protocol int) {
 // Tests that bloombits proofs can be correctly retrieved.
 func TestGetBloombitsProofs(t *testing.T) {
 	// Assemble the test environment
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	pm := newTestProtocolManagerMust(t, false, light.BloomTrieFrequency+256, testChainGen, nil, nil, db)
 	bc := pm.blockchain.(*core.BlockChain)
 	peer, _ := newTestPeer(t, "peer", 2, pm, true)
@@ -491,7 +488,7 @@ func TestGetBloombitsProofs(t *testing.T) {
 }
 
 func TestTransactionStatusLes2(t *testing.T) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	pm := newTestProtocolManagerMust(t, false, 0, nil, nil, nil, db)
 	chain := pm.blockchain.(*core.BlockChain)
 	config := core.DefaultTxPoolConfig
diff --git a/les/odr_test.go b/les/odr_test.go
index 9973df0430..983f7262b0 100644
--- a/les/odr_test.go
+++ b/les/odr_test.go
@@ -165,8 +165,8 @@ func testOdr(t *testing.T, protocol int, expFail uint64, fn odrTestFn) {
 	peers := newPeerSet()
 	dist := newRequestDistributor(peers, make(chan struct{}))
 	rm := newRetrieveManager(peers, dist, nil)
-	db, _ := ethdb.NewMemDatabase()
-	ldb, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
+	ldb := ethdb.NewMemDatabase()
 	odr := NewLesOdr(ldb, light.NewChtIndexer(db, true), light.NewBloomTrieIndexer(db, true), eth.NewBloomIndexer(db, light.BloomTrieFrequency), rm)
 	pm := newTestProtocolManagerMust(t, false, 4, testChainGen, nil, nil, db)
 	lpm := newTestProtocolManagerMust(t, true, 0, nil, peers, odr, ldb)
diff --git a/les/request_test.go b/les/request_test.go
index d4282a5927..ba2f603d8b 100644
--- a/les/request_test.go
+++ b/les/request_test.go
@@ -87,8 +87,8 @@ func testAccess(t *testing.T, protocol int, fn accessTestFn) {
 	peers := newPeerSet()
 	dist := newRequestDistributor(peers, make(chan struct{}))
 	rm := newRetrieveManager(peers, dist, nil)
-	db, _ := ethdb.NewMemDatabase()
-	ldb, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
+	ldb := ethdb.NewMemDatabase()
 	odr := NewLesOdr(ldb, light.NewChtIndexer(db, true), light.NewBloomTrieIndexer(db, true), eth.NewBloomIndexer(db, light.BloomTrieFrequency), rm)
 
 	pm := newTestProtocolManagerMust(t, false, 4, testChainGen, nil, nil, db)
diff --git a/light/lightchain_test.go b/light/lightchain_test.go
index b8ab1c51cf..c0aa51da29 100644
--- a/light/lightchain_test.go
+++ b/light/lightchain_test.go
@@ -52,7 +52,7 @@ func makeHeaderChain(parent *types.Header, n int, db ethdb.Database, seed int) [
 // chain. Depending on the full flag, if creates either a full block chain or a
 // header only chain.
 func newCanonical(n int) (ethdb.Database, *LightChain, error) {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	gspec := core.Genesis{Config: params.TestChainConfig}
 	genesis := gspec.MustCommit(db)
 	blockchain, _ := NewLightChain(&dummyOdr{db: db}, gspec.Config, ethash.NewFaker())
@@ -69,7 +69,7 @@ func newCanonical(n int) (ethdb.Database, *LightChain, error) {
 
 // newTestLightChain creates a LightChain that doesn't validate anything.
 func newTestLightChain() *LightChain {
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	gspec := &core.Genesis{
 		Difficulty: big.NewInt(1),
 		Config:     params.TestChainConfig,
diff --git a/light/odr_test.go b/light/odr_test.go
index cc7475df38..3e7ac10118 100644
--- a/light/odr_test.go
+++ b/light/odr_test.go
@@ -245,8 +245,8 @@ func testChainGen(i int, block *core.BlockGen) {
 
 func testChainOdr(t *testing.T, protocol int, fn odrTestFn) {
 	var (
-		sdb, _  = ethdb.NewMemDatabase()
-		ldb, _  = ethdb.NewMemDatabase()
+		sdb     = ethdb.NewMemDatabase()
+		ldb     = ethdb.NewMemDatabase()
 		gspec   = core.Genesis{Alloc: core.GenesisAlloc{testBankAddress: {Balance: testBankFunds}}}
 		genesis = gspec.MustCommit(sdb)
 	)
diff --git a/light/trie_test.go b/light/trie_test.go
index 0d6b2cc1d8..84c6f162fb 100644
--- a/light/trie_test.go
+++ b/light/trie_test.go
@@ -34,10 +34,10 @@ import (
 
 func TestNodeIterator(t *testing.T) {
 	var (
-		fulldb, _  = ethdb.NewMemDatabase()
-		lightdb, _ = ethdb.NewMemDatabase()
-		gspec      = core.Genesis{Alloc: core.GenesisAlloc{testBankAddress: {Balance: testBankFunds}}}
-		genesis    = gspec.MustCommit(fulldb)
+		fulldb  = ethdb.NewMemDatabase()
+		lightdb = ethdb.NewMemDatabase()
+		gspec   = core.Genesis{Alloc: core.GenesisAlloc{testBankAddress: {Balance: testBankFunds}}}
+		genesis = gspec.MustCommit(fulldb)
 	)
 	gspec.MustCommit(lightdb)
 	blockchain, _ := core.NewBlockChain(fulldb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{})
diff --git a/light/txpool_test.go b/light/txpool_test.go
index 13d7d3cebb..ccbd83a943 100644
--- a/light/txpool_test.go
+++ b/light/txpool_test.go
@@ -81,8 +81,8 @@ func TestTxPool(t *testing.T) {
 	}
 
 	var (
-		sdb, _  = ethdb.NewMemDatabase()
-		ldb, _  = ethdb.NewMemDatabase()
+		sdb     = ethdb.NewMemDatabase()
+		ldb     = ethdb.NewMemDatabase()
 		gspec   = core.Genesis{Alloc: core.GenesisAlloc{testBankAddress: {Balance: testBankFunds}}}
 		genesis = gspec.MustCommit(sdb)
 	)
diff --git a/node/node.go b/node/node.go
index 83b6c4c07e..c4368189f7 100644
--- a/node/node.go
+++ b/node/node.go
@@ -568,7 +568,7 @@ func (n *Node) EventMux() *event.TypeMux {
 // ephemeral, a memory database is returned.
 func (n *Node) OpenDatabase(name string, cache, handles int) (ethdb.Database, error) {
 	if n.config.DataDir == "" {
-		return ethdb.NewMemDatabase()
+		return ethdb.NewMemDatabase(), nil
 	}
 	return ethdb.NewLDBDatabase(n.config.resolvePath(name), cache, handles)
 }
diff --git a/node/service.go b/node/service.go
index 55062a5004..afc43e8486 100644
--- a/node/service.go
+++ b/node/service.go
@@ -41,7 +41,7 @@ type ServiceContext struct {
 // node is an ephemeral one, a memory database is returned.
 func (ctx *ServiceContext) OpenDatabase(name string, cache int, handles int) (ethdb.Database, error) {
 	if ctx.config.DataDir == "" {
-		return ethdb.NewMemDatabase()
+		return ethdb.NewMemDatabase(), nil
 	}
 	db, err := ethdb.NewLDBDatabase(ctx.config.resolvePath(name), cache, handles)
 	if err != nil {
diff --git a/p2p/peer.go b/p2p/peer.go
index 73e33418ed..c3907349fc 100644
--- a/p2p/peer.go
+++ b/p2p/peer.go
@@ -220,6 +220,7 @@ loop:
 			reason = discReasonForError(err)
 			break loop
 		case err = <-p.disc:
+			reason = discReasonForError(err)
 			break loop
 		}
 	}
diff --git a/tests/block_test_util.go b/tests/block_test_util.go
index 579e783b10..a72799f6e2 100644
--- a/tests/block_test_util.go
+++ b/tests/block_test_util.go
@@ -98,7 +98,7 @@ func (t *BlockTest) Run() error {
 	}
 
 	// import pre accounts & construct test genesis block & state root
-	db, _ := ethdb.NewMemDatabase()
+	db := ethdb.NewMemDatabase()
 	gblock, err := t.genesis(config).Commit(db)
 	if err != nil {
 		return err
diff --git a/tests/state_test_util.go b/tests/state_test_util.go
index 3b761bd771..84581fae18 100644
--- a/tests/state_test_util.go
+++ b/tests/state_test_util.go
@@ -126,8 +126,7 @@ func (t *StateTest) Run(subtest StateSubtest, vmconfig vm.Config) (*state.StateD
 		return nil, UnsupportedForkError{subtest.Fork}
 	}
 	block := t.genesis(config).ToBlock(nil)
-	db, _ := ethdb.NewMemDatabase()
-	statedb := MakePreState(db, t.json.Pre)
+	statedb := MakePreState(ethdb.NewMemDatabase(), t.json.Pre)
 
 	post := t.json.Post[subtest.Fork][subtest.Index]
 	msg, err := t.json.Tx.toMessage(post)
diff --git a/tests/vm_test_util.go b/tests/vm_test_util.go
index b365167a69..cb81c5b94e 100644
--- a/tests/vm_test_util.go
+++ b/tests/vm_test_util.go
@@ -79,8 +79,7 @@ type vmExecMarshaling struct {
 }
 
 func (t *VMTest) Run(vmconfig vm.Config) error {
-	db, _ := ethdb.NewMemDatabase()
-	statedb := MakePreState(db, t.json.Pre)
+	statedb := MakePreState(ethdb.NewMemDatabase(), t.json.Pre)
 	ret, gasRemaining, err := t.exec(statedb, vmconfig)
 
 	if t.json.GasRemaining == nil {
diff --git a/trie/iterator_test.go b/trie/iterator_test.go
index dce1c78b5d..2a510b1c2d 100644
--- a/trie/iterator_test.go
+++ b/trie/iterator_test.go
@@ -289,7 +289,7 @@ func TestIteratorContinueAfterErrorDisk(t *testing.T)    { testIteratorContinueA
 func TestIteratorContinueAfterErrorMemonly(t *testing.T) { testIteratorContinueAfterError(t, true) }
 
 func testIteratorContinueAfterError(t *testing.T, memonly bool) {
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 
 	tr, _ := New(common.Hash{}, triedb)
@@ -376,7 +376,7 @@ func TestIteratorContinueAfterSeekErrorMemonly(t *testing.T) {
 
 func testIteratorContinueAfterSeekError(t *testing.T, memonly bool) {
 	// Commit test trie to db, then remove the node containing "bars".
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 
 	ctr, _ := New(common.Hash{}, triedb)
diff --git a/trie/proof_test.go b/trie/proof_test.go
index fff313d7fd..a3537787cc 100644
--- a/trie/proof_test.go
+++ b/trie/proof_test.go
@@ -36,7 +36,7 @@ func TestProof(t *testing.T) {
 	trie, vals := randomTrie(500)
 	root := trie.Hash()
 	for _, kv := range vals {
-		proofs, _ := ethdb.NewMemDatabase()
+		proofs := ethdb.NewMemDatabase()
 		if trie.Prove(kv.k, 0, proofs) != nil {
 			t.Fatalf("missing key %x while constructing proof", kv.k)
 		}
@@ -53,7 +53,7 @@ func TestProof(t *testing.T) {
 func TestOneElementProof(t *testing.T) {
 	trie := new(Trie)
 	updateString(trie, "k", "v")
-	proofs, _ := ethdb.NewMemDatabase()
+	proofs := ethdb.NewMemDatabase()
 	trie.Prove([]byte("k"), 0, proofs)
 	if len(proofs.Keys()) != 1 {
 		t.Error("proof should have one element")
@@ -71,7 +71,7 @@ func TestVerifyBadProof(t *testing.T) {
 	trie, vals := randomTrie(800)
 	root := trie.Hash()
 	for _, kv := range vals {
-		proofs, _ := ethdb.NewMemDatabase()
+		proofs := ethdb.NewMemDatabase()
 		trie.Prove(kv.k, 0, proofs)
 		if len(proofs.Keys()) == 0 {
 			t.Fatal("zero length proof")
@@ -109,7 +109,7 @@ func BenchmarkProve(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		kv := vals[keys[i%len(keys)]]
-		proofs, _ := ethdb.NewMemDatabase()
+		proofs := ethdb.NewMemDatabase()
 		if trie.Prove(kv.k, 0, proofs); len(proofs.Keys()) == 0 {
 			b.Fatalf("zero length proof for %x", kv.k)
 		}
@@ -123,7 +123,7 @@ func BenchmarkVerifyProof(b *testing.B) {
 	var proofs []*ethdb.MemDatabase
 	for k := range vals {
 		keys = append(keys, k)
-		proof, _ := ethdb.NewMemDatabase()
+		proof := ethdb.NewMemDatabase()
 		trie.Prove([]byte(k), 0, proof)
 		proofs = append(proofs, proof)
 	}
diff --git a/trie/secure_trie_test.go b/trie/secure_trie_test.go
index aedf5a1cde..d16d999684 100644
--- a/trie/secure_trie_test.go
+++ b/trie/secure_trie_test.go
@@ -28,18 +28,14 @@ import (
 )
 
 func newEmptySecure() *SecureTrie {
-	diskdb, _ := ethdb.NewMemDatabase()
-	triedb := NewDatabase(diskdb)
-
-	trie, _ := NewSecure(common.Hash{}, triedb, 0)
+	trie, _ := NewSecure(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()), 0)
 	return trie
 }
 
 // makeTestSecureTrie creates a large enough secure trie for testing.
 func makeTestSecureTrie() (*Database, *SecureTrie, map[string][]byte) {
 	// Create an empty trie
-	diskdb, _ := ethdb.NewMemDatabase()
-	triedb := NewDatabase(diskdb)
+	triedb := NewDatabase(ethdb.NewMemDatabase())
 
 	trie, _ := NewSecure(common.Hash{}, triedb, 0)
 
diff --git a/trie/sync_test.go b/trie/sync_test.go
index 4a720612b6..142a6f5b1a 100644
--- a/trie/sync_test.go
+++ b/trie/sync_test.go
@@ -27,8 +27,7 @@ import (
 // makeTestTrie create a sample test trie to test node-wise reconstruction.
 func makeTestTrie() (*Database, *Trie, map[string][]byte) {
 	// Create an empty trie
-	diskdb, _ := ethdb.NewMemDatabase()
-	triedb := NewDatabase(diskdb)
+	triedb := NewDatabase(ethdb.NewMemDatabase())
 	trie, _ := New(common.Hash{}, triedb)
 
 	// Fill it with some arbitrary data
@@ -89,18 +88,13 @@ func checkTrieConsistency(db *Database, root common.Hash) error {
 
 // Tests that an empty trie is not scheduled for syncing.
 func TestEmptyTrieSync(t *testing.T) {
-	diskdbA, _ := ethdb.NewMemDatabase()
-	triedbA := NewDatabase(diskdbA)
-
-	diskdbB, _ := ethdb.NewMemDatabase()
-	triedbB := NewDatabase(diskdbB)
-
-	emptyA, _ := New(common.Hash{}, triedbA)
-	emptyB, _ := New(emptyRoot, triedbB)
+	dbA := NewDatabase(ethdb.NewMemDatabase())
+	dbB := NewDatabase(ethdb.NewMemDatabase())
+	emptyA, _ := New(common.Hash{}, dbA)
+	emptyB, _ := New(emptyRoot, dbB)
 
 	for i, trie := range []*Trie{emptyA, emptyB} {
-		diskdb, _ := ethdb.NewMemDatabase()
-		if req := NewTrieSync(trie.Hash(), diskdb, nil).Missing(1); len(req) != 0 {
+		if req := NewTrieSync(trie.Hash(), ethdb.NewMemDatabase(), nil).Missing(1); len(req) != 0 {
 			t.Errorf("test %d: content requested for empty trie: %v", i, req)
 		}
 	}
@@ -116,7 +110,7 @@ func testIterativeTrieSync(t *testing.T, batch int) {
 	srcDb, srcTrie, srcData := makeTestTrie()
 
 	// Create a destination trie and sync with the scheduler
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 	sched := NewTrieSync(srcTrie.Hash(), diskdb, nil)
 
@@ -149,7 +143,7 @@ func TestIterativeDelayedTrieSync(t *testing.T) {
 	srcDb, srcTrie, srcData := makeTestTrie()
 
 	// Create a destination trie and sync with the scheduler
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 	sched := NewTrieSync(srcTrie.Hash(), diskdb, nil)
 
@@ -187,7 +181,7 @@ func testIterativeRandomTrieSync(t *testing.T, batch int) {
 	srcDb, srcTrie, srcData := makeTestTrie()
 
 	// Create a destination trie and sync with the scheduler
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 	sched := NewTrieSync(srcTrie.Hash(), diskdb, nil)
 
@@ -228,7 +222,7 @@ func TestIterativeRandomDelayedTrieSync(t *testing.T) {
 	srcDb, srcTrie, srcData := makeTestTrie()
 
 	// Create a destination trie and sync with the scheduler
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 	sched := NewTrieSync(srcTrie.Hash(), diskdb, nil)
 
@@ -275,7 +269,7 @@ func TestDuplicateAvoidanceTrieSync(t *testing.T) {
 	srcDb, srcTrie, srcData := makeTestTrie()
 
 	// Create a destination trie and sync with the scheduler
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 	sched := NewTrieSync(srcTrie.Hash(), diskdb, nil)
 
@@ -315,7 +309,7 @@ func TestIncompleteTrieSync(t *testing.T) {
 	srcDb, srcTrie, _ := makeTestTrie()
 
 	// Create a destination trie and sync with the scheduler
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 	sched := NewTrieSync(srcTrie.Hash(), diskdb, nil)
 
diff --git a/trie/trie_test.go b/trie/trie_test.go
index 9972226288..f8e5fd12a1 100644
--- a/trie/trie_test.go
+++ b/trie/trie_test.go
@@ -43,8 +43,7 @@ func init() {
 
 // Used for testing
 func newEmpty() *Trie {
-	diskdb, _ := ethdb.NewMemDatabase()
-	trie, _ := New(common.Hash{}, NewDatabase(diskdb))
+	trie, _ := New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
 	return trie
 }
 
@@ -68,8 +67,7 @@ func TestNull(t *testing.T) {
 }
 
 func TestMissingRoot(t *testing.T) {
-	diskdb, _ := ethdb.NewMemDatabase()
-	trie, err := New(common.HexToHash("0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33"), NewDatabase(diskdb))
+	trie, err := New(common.HexToHash("0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33"), NewDatabase(ethdb.NewMemDatabase()))
 	if trie != nil {
 		t.Error("New returned non-nil trie for invalid root")
 	}
@@ -82,7 +80,7 @@ func TestMissingNodeDisk(t *testing.T)    { testMissingNode(t, false) }
 func TestMissingNodeMemonly(t *testing.T) { testMissingNode(t, true) }
 
 func testMissingNode(t *testing.T, memonly bool) {
-	diskdb, _ := ethdb.NewMemDatabase()
+	diskdb := ethdb.NewMemDatabase()
 	triedb := NewDatabase(diskdb)
 
 	trie, _ := New(common.Hash{}, triedb)
@@ -413,8 +411,7 @@ func (randTest) Generate(r *rand.Rand, size int) reflect.Value {
 }
 
 func runRandTest(rt randTest) bool {
-	diskdb, _ := ethdb.NewMemDatabase()
-	triedb := NewDatabase(diskdb)
+	triedb := NewDatabase(ethdb.NewMemDatabase())
 
 	tr, _ := New(common.Hash{}, triedb)
 	values := make(map[string]string) // tracks content of the trie
diff --git a/whisper/shhclient/client.go b/whisper/shhclient/client.go
index 7b25e739e1..8e7085a0a6 100644
--- a/whisper/shhclient/client.go
+++ b/whisper/shhclient/client.go
@@ -135,9 +135,9 @@ func (sc *Client) AddSymmetricKey(ctx context.Context, key []byte) (string, erro
 }
 
 // GenerateSymmetricKeyFromPassword generates the key from password, stores it, and returns its identifier.
-func (sc *Client) GenerateSymmetricKeyFromPassword(ctx context.Context, passwd []byte) (string, error) {
+func (sc *Client) GenerateSymmetricKeyFromPassword(ctx context.Context, passwd string) (string, error) {
 	var id string
-	return id, sc.c.CallContext(ctx, &id, "shh_generateSymKeyFromPassword", hexutil.Bytes(passwd))
+	return id, sc.c.CallContext(ctx, &id, "shh_generateSymKeyFromPassword", passwd)
 }
 
 // HasSymmetricKey returns an indication if the key associated with the given id is stored in the node.