diff --git a/accounts/abi/reflect.go b/accounts/abi/reflect.go
index 11248e07302eb..35e5556d2c5a7 100644
--- a/accounts/abi/reflect.go
+++ b/accounts/abi/reflect.go
@@ -123,15 +123,8 @@ func set(dst, src reflect.Value) error {
 func setSlice(dst, src reflect.Value) error {
 	slice := reflect.MakeSlice(dst.Type(), src.Len(), src.Len())
 	for i := 0; i < src.Len(); i++ {
-		if src.Index(i).Kind() == reflect.Struct {
-			if err := set(slice.Index(i), src.Index(i)); err != nil {
-				return err
-			}
-		} else {
-			// e.g. [][32]uint8 to []common.Hash
-			if err := set(slice.Index(i), src.Index(i)); err != nil {
-				return err
-			}
+		if err := set(slice.Index(i), src.Index(i)); err != nil {
+			return err
 		}
 	}
 	if dst.CanSet() {
diff --git a/cmd/evm/internal/t8ntool/transition.go b/cmd/evm/internal/t8ntool/transition.go
index 7407ed0a44b54..88a9c5e62235e 100644
--- a/cmd/evm/internal/t8ntool/transition.go
+++ b/cmd/evm/internal/t8ntool/transition.go
@@ -419,7 +419,7 @@ func dispatchOutput(ctx *cli.Context, baseDir string, result *ExecutionResult, a
 			return NewError(ErrorJson, fmt.Errorf("failed marshalling output: %v", err))
 		}
 		os.Stdout.Write(b)
-		os.Stdout.Write([]byte("\n"))
+		os.Stdout.WriteString("\n")
 	}
 	if len(stdErrObject) > 0 {
 		b, err := json.MarshalIndent(stdErrObject, "", "  ")
@@ -427,7 +427,7 @@ func dispatchOutput(ctx *cli.Context, baseDir string, result *ExecutionResult, a
 			return NewError(ErrorJson, fmt.Errorf("failed marshalling output: %v", err))
 		}
 		os.Stderr.Write(b)
-		os.Stderr.Write([]byte("\n"))
+		os.Stderr.WriteString("\n")
 	}
 	return nil
 }
diff --git a/cmd/faucet/faucet.go b/cmd/faucet/faucet.go
index c502f67bc565a..bbe84562726bd 100644
--- a/cmd/faucet/faucet.go
+++ b/cmd/faucet/faucet.go
@@ -741,7 +741,7 @@ func authTwitter(url string, tokenV1, tokenV2 string) (string, string, string, c
 		return "", "", "", common.Address{}, errors.New("No Ethereum address found to fund")
 	}
 	var avatar string
-	if parts = regexp.MustCompile("src=\"([^\"]+twimg.com/profile_images[^\"]+)\"").FindStringSubmatch(string(body)); len(parts) == 2 {
+	if parts = regexp.MustCompile(`src="([^"]+twimg\.com/profile_images[^"]+)"`).FindStringSubmatch(string(body)); len(parts) == 2 {
 		avatar = parts[1]
 	}
 	return username + "@twitter", username, avatar, address, nil
@@ -867,7 +867,7 @@ func authFacebook(url string) (string, string, common.Address, error) {
 		return "", "", common.Address{}, errors.New("No Ethereum address found to fund")
 	}
 	var avatar string
-	if parts = regexp.MustCompile("src=\"([^\"]+fbcdn.net[^\"]+)\"").FindStringSubmatch(string(body)); len(parts) == 2 {
+	if parts = regexp.MustCompile(`src="([^"]+fbcdn\.net[^"]+)"`).FindStringSubmatch(string(body)); len(parts) == 2 {
 		avatar = parts[1]
 	}
 	return username + "@facebook", avatar, address, nil
diff --git a/core/bloombits/generator_test.go b/core/bloombits/generator_test.go
index 88e3ed6b06c0d..883948d12bbab 100644
--- a/core/bloombits/generator_test.go
+++ b/core/bloombits/generator_test.go
@@ -70,7 +70,7 @@ func BenchmarkGenerator(b *testing.B) {
 			if err != nil {
 				b.Fatalf("failed to create bloombit generator: %v", err)
 			}
-			for j, bloom := range input {
+			for j, bloom := range &input {
 				if err := gen.AddBloom(uint(j), bloom); err != nil {
 					b.Fatalf("bloom %d: failed to add: %v", i, err)
 				}
@@ -89,7 +89,7 @@ func BenchmarkGenerator(b *testing.B) {
 			if err != nil {
 				b.Fatalf("failed to create bloombit generator: %v", err)
 			}
-			for j, bloom := range input {
+			for j, bloom := range &input {
 				if err := gen.AddBloom(uint(j), bloom); err != nil {
 					b.Fatalf("bloom %d: failed to add: %v", i, err)
 				}
diff --git a/eth/protocols/eth/handler_test.go b/eth/protocols/eth/handler_test.go
index d88965c15759a..66f013409694c 100644
--- a/eth/protocols/eth/handler_test.go
+++ b/eth/protocols/eth/handler_test.go
@@ -385,7 +385,7 @@ func testGetNodeData(t *testing.T, protocol uint) {
 	acc2Addr := crypto.PubkeyToAddress(acc2Key.PublicKey)
 
 	signer := types.HomesteadSigner{}
-	// Create a chain generator with some simple transactions (blatantly stolen from @fjl/chain_markets_test)
+	// Create a chain generator with some simple transactions (blatantly stolen from @fjl/chain_makers_test)
 	generator := func(i int, block *core.BlockGen) {
 		switch i {
 		case 0:
@@ -420,9 +420,8 @@ func testGetNodeData(t *testing.T, protocol uint) {
 	peer, _ := newTestPeer("peer", protocol, backend)
 	defer peer.close()
 
-	// Fetch for now the entire chain db
+	// Collect all state tree hashes.
 	var hashes []common.Hash
-
 	it := backend.db.NewIterator(nil, nil)
 	for it.Next() {
 		if key := it.Key(); len(key) == common.HashLength {
@@ -431,6 +430,7 @@ func testGetNodeData(t *testing.T, protocol uint) {
 	}
 	it.Release()
 
+	// Request all hashes.
 	p2p.Send(peer.app, GetNodeDataMsg, GetNodeDataPacket66{
 		RequestId:         123,
 		GetNodeDataPacket: hashes,
@@ -442,38 +442,40 @@ func testGetNodeData(t *testing.T, protocol uint) {
 	if msg.Code != NodeDataMsg {
 		t.Fatalf("response packet code mismatch: have %x, want %x", msg.Code, NodeDataMsg)
 	}
-	var (
-		data [][]byte
-		res  NodeDataPacket66
-	)
+	var res NodeDataPacket66
 	if err := msg.Decode(&res); err != nil {
 		t.Fatalf("failed to decode response node data: %v", err)
 	}
-	data = res.NodeDataPacket
-	// Verify that all hashes correspond to the requested data, and reconstruct a state tree
+
+	// Verify that all hashes correspond to the requested data.
+	data := res.NodeDataPacket
 	for i, want := range hashes {
 		if hash := crypto.Keccak256Hash(data[i]); hash != want {
 			t.Errorf("data hash mismatch: have %x, want %x", hash, want)
 		}
 	}
-	statedb := rawdb.NewMemoryDatabase()
+
+	// Reconstruct state tree from the received data.
+	reconstructDB := rawdb.NewMemoryDatabase()
 	for i := 0; i < len(data); i++ {
-		statedb.Put(hashes[i].Bytes(), data[i])
+		rawdb.WriteTrieNode(reconstructDB, hashes[i], data[i])
 	}
+
+	// Sanity check whether all state matches.
 	accounts := []common.Address{testAddr, acc1Addr, acc2Addr}
 	for i := uint64(0); i <= backend.chain.CurrentBlock().NumberU64(); i++ {
-		trie, _ := state.New(backend.chain.GetBlockByNumber(i).Root(), state.NewDatabase(statedb), nil)
-
+		root := backend.chain.GetBlockByNumber(i).Root()
+		reconstructed, _ := state.New(root, state.NewDatabase(reconstructDB), nil)
 		for j, acc := range accounts {
-			state, _ := backend.chain.State()
+			state, _ := backend.chain.StateAt(root)
 			bw := state.GetBalance(acc)
-			bh := trie.GetBalance(acc)
+			bh := reconstructed.GetBalance(acc)
 
-			if (bw != nil && bh == nil) || (bw == nil && bh != nil) {
-				t.Errorf("test %d, account %d: balance mismatch: have %v, want %v", i, j, bh, bw)
+			if (bw == nil) != (bh == nil) {
+				t.Errorf("block %d, account %d: balance mismatch: have %v, want %v", i, j, bh, bw)
 			}
-			if bw != nil && bh != nil && bw.Cmp(bw) != 0 {
-				t.Errorf("test %d, account %d: balance mismatch: have %v, want %v", i, j, bh, bw)
+			if bw != nil && bh != nil && bw.Cmp(bh) != 0 {
+				t.Errorf("block %d, account %d: balance mismatch: have %v, want %v", i, j, bh, bw)
 			}
 		}
 	}
diff --git a/node/api.go b/node/api.go
index be20b89d95c05..a685ecd6b3347 100644
--- a/node/api.go
+++ b/node/api.go
@@ -218,7 +218,7 @@ func (api *privateAdminAPI) StartHTTP(host *string, port *int, cors *string, api
 }
 
 // StartRPC starts the HTTP RPC API server.
-// This method is deprecated. Use StartHTTP instead.
+// Deprecated: use StartHTTP instead.
 func (api *privateAdminAPI) StartRPC(host *string, port *int, cors *string, apis *string, vhosts *string) (bool, error) {
 	log.Warn("Deprecation warning", "method", "admin.StartRPC", "use-instead", "admin.StartHTTP")
 	return api.StartHTTP(host, port, cors, apis, vhosts)
@@ -231,7 +231,7 @@ func (api *privateAdminAPI) StopHTTP() (bool, error) {
 }
 
 // StopRPC shuts down the HTTP server.
-// This method is deprecated. Use StopHTTP instead.
+// Deprecated: use StopHTTP instead.
 func (api *privateAdminAPI) StopRPC() (bool, error) {
 	log.Warn("Deprecation warning", "method", "admin.StopRPC", "use-instead", "admin.StopHTTP")
 	return api.StopHTTP()
diff --git a/signer/core/signed_data.go b/signer/core/signed_data.go
index 6c2fd5f8fefc3..daa84313dab84 100644
--- a/signer/core/signed_data.go
+++ b/signer/core/signed_data.go
@@ -29,6 +29,7 @@ import (
 	"strconv"
 	"strings"
 	"unicode"
+	"unicode/utf8"
 
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
@@ -100,7 +101,8 @@ func (t *Type) isReferenceType() bool {
 		return false
 	}
 	// Reference types must have a leading uppercase character
-	return unicode.IsUpper([]rune(t.Type)[0])
+	r, _ := utf8.DecodeRuneInString(t.Type)
+	return unicode.IsUpper(r)
 }
 
 type Types map[string][]Type
diff --git a/signer/core/validation.go b/signer/core/validation.go
index af858862ef4a8..7639dbf64916e 100644
--- a/signer/core/validation.go
+++ b/signer/core/validation.go
@@ -21,7 +21,7 @@ import (
 	"regexp"
 )
 
-var printable7BitAscii = regexp.MustCompile("^[A-Za-z0-9!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~ ]+$")
+var printable7BitAscii = regexp.MustCompile("^[A-Za-z0-9!\"#$%&'()*+,\\-./:;<=>?@[\\]^_`{|}~ ]+$")
 
 // ValidatePasswordFormat returns an error if the password is too short, or consists of characters
 // outside the range of the printable 7bit ascii set