diff --git a/.travis.yml b/.travis.yml
index 194ca63969..09b77d09d7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -126,7 +126,7 @@ matrix:
 
     # This builder does the Android Maven and Azure uploads
     - os: linux
-      dist: precise # Needed for the android tools
+      dist: trusty
       addons:
         apt:
           packages:
@@ -152,10 +152,10 @@ matrix:
         - export GOPATH=$HOME/go
       script:
         # Build the Android archive and upload it to Maven Central and Azure
-        - curl https://dl.google.com/android/repository/android-ndk-r15c-linux-x86_64.zip -o android-ndk-r15c.zip
-        - unzip -q android-ndk-r15c.zip && rm android-ndk-r15c.zip
-        - mv android-ndk-r15c $HOME
-        - export ANDROID_NDK=$HOME/android-ndk-r15c
+        - curl https://dl.google.com/android/repository/android-ndk-r16b-linux-x86_64.zip -o android-ndk-r16b.zip
+        - unzip -q android-ndk-r16b.zip && rm android-ndk-r16b.zip
+        - mv android-ndk-r16b $HOME
+        - export ANDROID_NDK=$HOME/android-ndk-r16b
 
         - mkdir -p $GOPATH/src/github.com/ethereum
         - ln -s `pwd` $GOPATH/src/github.com/ethereum
diff --git a/VERSION b/VERSION
index 1790d35988..53ed4ba51e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.8.8
+1.8.9
diff --git a/accounts/abi/argument.go b/accounts/abi/argument.go
index 512d8fdfa7..93b513c346 100644
--- a/accounts/abi/argument.go
+++ b/accounts/abi/argument.go
@@ -111,9 +111,14 @@ func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interfa
 	if err := requireUnpackKind(value, typ, kind, arguments); err != nil {
 		return err
 	}
-	// If the output interface is a struct, make sure names don't collide
+
+	// If the interface is a struct, get of abi->struct_field mapping
+
+	var abi2struct map[string]string
 	if kind == reflect.Struct {
-		if err := requireUniqueStructFieldNames(arguments); err != nil {
+		var err error
+		abi2struct, err = mapAbiToStructFields(arguments, value)
+		if err != nil {
 			return err
 		}
 	}
@@ -123,9 +128,10 @@ func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interfa
 
 		switch kind {
 		case reflect.Struct:
-			err := unpackStruct(value, reflectValue, arg)
-			if err != nil {
-				return err
+			if structField, ok := abi2struct[arg.Name]; ok {
+				if err := set(value.FieldByName(structField), reflectValue, arg); err != nil {
+					return err
+				}
 			}
 		case reflect.Slice, reflect.Array:
 			if value.Len() < i {
@@ -151,17 +157,22 @@ func (arguments Arguments) unpackAtomic(v interface{}, marshalledValues []interf
 	if len(marshalledValues) != 1 {
 		return fmt.Errorf("abi: wrong length, expected single value, got %d", len(marshalledValues))
 	}
+
 	elem := reflect.ValueOf(v).Elem()
 	kind := elem.Kind()
 	reflectValue := reflect.ValueOf(marshalledValues[0])
 
+	var abi2struct map[string]string
 	if kind == reflect.Struct {
-		//make sure names don't collide
-		if err := requireUniqueStructFieldNames(arguments); err != nil {
+		var err error
+		if abi2struct, err = mapAbiToStructFields(arguments, elem); err != nil {
 			return err
 		}
-
-		return unpackStruct(elem, reflectValue, arguments[0])
+		arg := arguments.NonIndexed()[0]
+		if structField, ok := abi2struct[arg.Name]; ok {
+			return set(elem.FieldByName(structField), reflectValue, arg)
+		}
+		return nil
 	}
 
 	return set(elem, reflectValue, arguments.NonIndexed()[0])
@@ -277,18 +288,3 @@ func capitalise(input string) string {
 	}
 	return strings.ToUpper(input[:1]) + input[1:]
 }
-
-//unpackStruct extracts each argument into its corresponding struct field
-func unpackStruct(value, reflectValue reflect.Value, arg Argument) error {
-	name := capitalise(arg.Name)
-	typ := value.Type()
-	for j := 0; j < typ.NumField(); j++ {
-		// TODO read tags: `abi:"fieldName"`
-		if typ.Field(j).Name == name {
-			if err := set(value.Field(j), reflectValue, arg); err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}
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/accounts/abi/event_test.go b/accounts/abi/event_test.go
index cca61e433d..3bfdd7c0ab 100644
--- a/accounts/abi/event_test.go
+++ b/accounts/abi/event_test.go
@@ -58,12 +58,28 @@ var jsonEventPledge = []byte(`{
   "type": "event"
 }`)
 
+var jsonEventMixedCase = []byte(`{
+	"anonymous": false,
+	"inputs": [{
+		"indexed": false, "name": "value", "type": "uint256"
+	  }, {
+		"indexed": false, "name": "_value", "type": "uint256"
+	  }, {
+		"indexed": false, "name": "Value", "type": "uint256"
+	}],
+	"name": "MixedCase",
+	"type": "event"
+  }`)
+
 // 1000000
 var transferData1 = "00000000000000000000000000000000000000000000000000000000000f4240"
 
 // "0x00Ce0d46d924CC8437c806721496599FC3FFA268", 2218516807680, "usd"
 var pledgeData1 = "00000000000000000000000000ce0d46d924cc8437c806721496599fc3ffa2680000000000000000000000000000000000000000000000000000020489e800007573640000000000000000000000000000000000000000000000000000000000"
 
+// 1000000,2218516807680,1000001
+var mixedCaseData1 = "00000000000000000000000000000000000000000000000000000000000f42400000000000000000000000000000000000000000000000000000020489e8000000000000000000000000000000000000000000000000000000000000000f4241"
+
 func TestEventId(t *testing.T) {
 	var table = []struct {
 		definition   string
@@ -121,6 +137,27 @@ func TestEventTupleUnpack(t *testing.T) {
 		Value *big.Int
 	}
 
+	type EventTransferWithTag struct {
+		// this is valid because `value` is not exportable,
+		// so value is only unmarshalled into `Value1`.
+		value  *big.Int
+		Value1 *big.Int `abi:"value"`
+	}
+
+	type BadEventTransferWithSameFieldAndTag struct {
+		Value  *big.Int
+		Value1 *big.Int `abi:"value"`
+	}
+
+	type BadEventTransferWithDuplicatedTag struct {
+		Value1 *big.Int `abi:"value"`
+		Value2 *big.Int `abi:"value"`
+	}
+
+	type BadEventTransferWithEmptyTag struct {
+		Value *big.Int `abi:""`
+	}
+
 	type EventPledge struct {
 		Who      common.Address
 		Wad      *big.Int
@@ -133,9 +170,16 @@ func TestEventTupleUnpack(t *testing.T) {
 		Currency [3]byte
 	}
 
+	type EventMixedCase struct {
+		Value1 *big.Int `abi:"value"`
+		Value2 *big.Int `abi:"_value"`
+		Value3 *big.Int `abi:"Value"`
+	}
+
 	bigint := new(big.Int)
 	bigintExpected := big.NewInt(1000000)
 	bigintExpected2 := big.NewInt(2218516807680)
+	bigintExpected3 := big.NewInt(1000001)
 	addr := common.HexToAddress("0x00Ce0d46d924CC8437c806721496599FC3FFA268")
 	var testCases = []struct {
 		data     string
@@ -158,6 +202,34 @@ func TestEventTupleUnpack(t *testing.T) {
 		jsonEventTransfer,
 		"",
 		"Can unpack ERC20 Transfer event into slice",
+	}, {
+		transferData1,
+		&EventTransferWithTag{},
+		&EventTransferWithTag{Value1: bigintExpected},
+		jsonEventTransfer,
+		"",
+		"Can unpack ERC20 Transfer event into structure with abi: tag",
+	}, {
+		transferData1,
+		&BadEventTransferWithDuplicatedTag{},
+		&BadEventTransferWithDuplicatedTag{},
+		jsonEventTransfer,
+		"struct: abi tag in 'Value2' already mapped",
+		"Can not unpack ERC20 Transfer event with duplicated abi tag",
+	}, {
+		transferData1,
+		&BadEventTransferWithSameFieldAndTag{},
+		&BadEventTransferWithSameFieldAndTag{},
+		jsonEventTransfer,
+		"abi: multiple variables maps to the same abi field 'value'",
+		"Can not unpack ERC20 Transfer event with a field and a tag mapping to the same abi variable",
+	}, {
+		transferData1,
+		&BadEventTransferWithEmptyTag{},
+		&BadEventTransferWithEmptyTag{},
+		jsonEventTransfer,
+		"struct: abi tag in 'Value' is empty",
+		"Can not unpack ERC20 Transfer event with an empty tag",
 	}, {
 		pledgeData1,
 		&EventPledge{},
@@ -216,6 +288,13 @@ func TestEventTupleUnpack(t *testing.T) {
 		jsonEventPledge,
 		"abi: cannot unmarshal tuple into map[string]interface {}",
 		"Can not unpack Pledge event into map",
+	}, {
+		mixedCaseData1,
+		&EventMixedCase{},
+		&EventMixedCase{Value1: bigintExpected, Value2: bigintExpected2, Value3: bigintExpected3},
+		jsonEventMixedCase,
+		"",
+		"Can unpack abi variables with mixed case",
 	}}
 
 	for _, tc := range testCases {
@@ -227,7 +306,7 @@ func TestEventTupleUnpack(t *testing.T) {
 				assert.Nil(err, "Should be able to unpack event data.")
 				assert.Equal(tc.expected, tc.dest, tc.name)
 			} else {
-				assert.EqualError(err, tc.error)
+				assert.EqualError(err, tc.error, tc.name)
 			}
 		})
 	}
diff --git a/accounts/abi/reflect.go b/accounts/abi/reflect.go
index 5620a70845..0193517a42 100644
--- a/accounts/abi/reflect.go
+++ b/accounts/abi/reflect.go
@@ -19,6 +19,7 @@ package abi
 import (
 	"fmt"
 	"reflect"
+	"strings"
 )
 
 // indirect recursively dereferences the value until it either gets the value
@@ -111,18 +112,101 @@ func requireUnpackKind(v reflect.Value, t reflect.Type, k reflect.Kind,
 	return nil
 }
 
-// requireUniqueStructFieldNames makes sure field names don't collide
-func requireUniqueStructFieldNames(args Arguments) error {
-	exists := make(map[string]bool)
-	for _, arg := range args {
-		field := capitalise(arg.Name)
-		if field == "" {
-			return fmt.Errorf("abi: purely underscored output cannot unpack to struct")
+// mapAbiToStringField maps abi to struct fields.
+// first round: for each Exportable field that contains a `abi:""` tag
+//   and this field name exists in the arguments, pair them together.
+// second round: for each argument field that has not been already linked,
+//   find what variable is expected to be mapped into, if it exists and has not been
+//   used, pair them.
+func mapAbiToStructFields(args Arguments, value reflect.Value) (map[string]string, error) {
+
+	typ := value.Type()
+
+	abi2struct := make(map[string]string)
+	struct2abi := make(map[string]string)
+
+	// first round ~~~
+	for i := 0; i < typ.NumField(); i++ {
+		structFieldName := typ.Field(i).Name
+
+		// skip private struct fields.
+		if structFieldName[:1] != strings.ToUpper(structFieldName[:1]) {
+			continue
 		}
-		if exists[field] {
-			return fmt.Errorf("abi: multiple outputs mapping to the same struct field '%s'", field)
+
+		// skip fields that have no abi:"" tag.
+		var ok bool
+		var tagName string
+		if tagName, ok = typ.Field(i).Tag.Lookup("abi"); !ok {
+			continue
 		}
-		exists[field] = true
+
+		// check if tag is empty.
+		if tagName == "" {
+			return nil, fmt.Errorf("struct: abi tag in '%s' is empty", structFieldName)
+		}
+
+		// check which argument field matches with the abi tag.
+		found := false
+		for _, abiField := range args.NonIndexed() {
+			if abiField.Name == tagName {
+				if abi2struct[abiField.Name] != "" {
+					return nil, fmt.Errorf("struct: abi tag in '%s' already mapped", structFieldName)
+				}
+				// pair them
+				abi2struct[abiField.Name] = structFieldName
+				struct2abi[structFieldName] = abiField.Name
+				found = true
+			}
+		}
+
+		// check if this tag has been mapped.
+		if !found {
+			return nil, fmt.Errorf("struct: abi tag '%s' defined but not found in abi", tagName)
+		}
+
 	}
-	return nil
+
+	// second round ~~~
+	for _, arg := range args {
+
+		abiFieldName := arg.Name
+		structFieldName := capitalise(abiFieldName)
+
+		if structFieldName == "" {
+			return nil, fmt.Errorf("abi: purely underscored output cannot unpack to struct")
+		}
+
+		// this abi has already been paired, skip it... unless there exists another, yet unassigned
+		// struct field with the same field name. If so, raise an error:
+		//    abi: [ { "name": "value" } ]
+		//    struct { Value  *big.Int , Value1 *big.Int `abi:"value"`}
+		if abi2struct[abiFieldName] != "" {
+			if abi2struct[abiFieldName] != structFieldName &&
+				struct2abi[structFieldName] == "" &&
+				value.FieldByName(structFieldName).IsValid() {
+				return nil, fmt.Errorf("abi: multiple variables maps to the same abi field '%s'", abiFieldName)
+			}
+			continue
+		}
+
+		// return an error if this struct field has already been paired.
+		if struct2abi[structFieldName] != "" {
+			return nil, fmt.Errorf("abi: multiple outputs mapping to the same struct field '%s'", structFieldName)
+		}
+
+		if value.FieldByName(structFieldName).IsValid() {
+			// pair them
+			abi2struct[abiFieldName] = structFieldName
+			struct2abi[structFieldName] = abiFieldName
+		} else {
+			// not paired, but annotate as used, to detect cases like
+			//   abi : [ { "name": "value" }, { "name": "_value" } ]
+			//   struct { Value *big.Int }
+			struct2abi[structFieldName] = abiFieldName
+		}
+
+	}
+
+	return abi2struct, nil
 }
diff --git a/bmt/bmt.go b/bmt/bmt.go
index 3408758675..c290223452 100644
--- a/bmt/bmt.go
+++ b/bmt/bmt.go
@@ -150,29 +150,29 @@ func NewTreePool(hasher BaseHasher, segmentCount, capacity int) *TreePool {
 }
 
 // Drain drains the pool until it has no more than n resources
-func (self *TreePool) Drain(n int) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	for len(self.c) > n {
-		<-self.c
-		self.count--
+func (p *TreePool) Drain(n int) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	for len(p.c) > n {
+		<-p.c
+		p.count--
 	}
 }
 
 // Reserve is blocking until it returns an available Tree
 // it reuses free Trees or creates a new one if size is not reached
-func (self *TreePool) Reserve() *Tree {
-	self.lock.Lock()
-	defer self.lock.Unlock()
+func (p *TreePool) Reserve() *Tree {
+	p.lock.Lock()
+	defer p.lock.Unlock()
 	var t *Tree
-	if self.count == self.Capacity {
-		return <-self.c
+	if p.count == p.Capacity {
+		return <-p.c
 	}
 	select {
-	case t = <-self.c:
+	case t = <-p.c:
 	default:
-		t = NewTree(self.hasher, self.SegmentSize, self.SegmentCount)
-		self.count++
+		t = NewTree(p.hasher, p.SegmentSize, p.SegmentCount)
+		p.count++
 	}
 	return t
 }
@@ -180,8 +180,8 @@ func (self *TreePool) Reserve() *Tree {
 // Release gives back a Tree to the pool.
 // This Tree is guaranteed to be in reusable state
 // does not need locking
-func (self *TreePool) Release(t *Tree) {
-	self.c <- t // can never fail but...
+func (p *TreePool) Release(t *Tree) {
+	p.c <- t // can never fail but...
 }
 
 // Tree is a reusable control structure representing a BMT
@@ -193,17 +193,17 @@ type Tree struct {
 }
 
 // Draw draws the BMT (badly)
-func (self *Tree) Draw(hash []byte, d int) string {
+func (t *Tree) Draw(hash []byte, d int) string {
 	var left, right []string
 	var anc []*Node
-	for i, n := range self.leaves {
+	for i, n := range t.leaves {
 		left = append(left, fmt.Sprintf("%v", hashstr(n.left)))
 		if i%2 == 0 {
 			anc = append(anc, n.parent)
 		}
 		right = append(right, fmt.Sprintf("%v", hashstr(n.right)))
 	}
-	anc = self.leaves
+	anc = t.leaves
 	var hashes [][]string
 	for l := 0; len(anc) > 0; l++ {
 		var nodes []*Node
@@ -277,42 +277,42 @@ func NewTree(hasher BaseHasher, segmentSize, segmentCount int) *Tree {
 // methods needed by hash.Hash
 
 // Size returns the size
-func (self *Hasher) Size() int {
-	return self.size
+func (h *Hasher) Size() int {
+	return h.size
 }
 
 // BlockSize returns the block size
-func (self *Hasher) BlockSize() int {
-	return self.blocksize
+func (h *Hasher) BlockSize() int {
+	return h.blocksize
 }
 
 // Sum returns the hash of the buffer
 // hash.Hash interface Sum method appends the byte slice to the underlying
 // data before it calculates and returns the hash of the chunk
-func (self *Hasher) Sum(b []byte) (r []byte) {
-	t := self.bmt
-	i := self.cur
+func (h *Hasher) Sum(b []byte) (r []byte) {
+	t := h.bmt
+	i := h.cur
 	n := t.leaves[i]
 	j := i
 	// must run strictly before all nodes calculate
 	// datanodes are guaranteed to have a parent
-	if len(self.segment) > self.size && i > 0 && n.parent != nil {
+	if len(h.segment) > h.size && i > 0 && n.parent != nil {
 		n = n.parent
 	} else {
 		i *= 2
 	}
-	d := self.finalise(n, i)
-	self.writeSegment(j, self.segment, d)
-	c := <-self.result
-	self.releaseTree()
+	d := h.finalise(n, i)
+	h.writeSegment(j, h.segment, d)
+	c := <-h.result
+	h.releaseTree()
 
 	// sha3(length + BMT(pure_chunk))
-	if self.blockLength == nil {
+	if h.blockLength == nil {
 		return c
 	}
-	res := self.pool.hasher()
+	res := h.pool.hasher()
 	res.Reset()
-	res.Write(self.blockLength)
+	res.Write(h.blockLength)
 	res.Write(c)
 	return res.Sum(nil)
 }
@@ -321,8 +321,8 @@ func (self *Hasher) Sum(b []byte) (r []byte) {
 
 // Hash waits for the hasher result and returns it
 // caller must call this on a BMT Hasher being written to
-func (self *Hasher) Hash() []byte {
-	return <-self.result
+func (h *Hasher) Hash() []byte {
+	return <-h.result
 }
 
 // Hasher implements the io.Writer interface
@@ -330,16 +330,16 @@ func (self *Hasher) Hash() []byte {
 // Write fills the buffer to hash
 // with every full segment complete launches a hasher go routine
 // that shoots up the BMT
-func (self *Hasher) Write(b []byte) (int, error) {
+func (h *Hasher) Write(b []byte) (int, error) {
 	l := len(b)
 	if l <= 0 {
 		return 0, nil
 	}
-	s := self.segment
-	i := self.cur
-	count := (self.count + 1) / 2
-	need := self.count*self.size - self.cur*2*self.size
-	size := self.size
+	s := h.segment
+	i := h.cur
+	count := (h.count + 1) / 2
+	need := h.count*h.size - h.cur*2*h.size
+	size := h.size
 	if need > size {
 		size *= 2
 	}
@@ -356,7 +356,7 @@ func (self *Hasher) Write(b []byte) (int, error) {
 	// read full segments and the last possibly partial segment
 	for need > 0 && i < count-1 {
 		// push all finished chunks we read
-		self.writeSegment(i, s, self.depth)
+		h.writeSegment(i, s, h.depth)
 		need -= size
 		if need < 0 {
 			size += need
@@ -365,8 +365,8 @@ func (self *Hasher) Write(b []byte) (int, error) {
 		rest += size
 		i++
 	}
-	self.segment = s
-	self.cur = i
+	h.segment = s
+	h.cur = i
 	// otherwise, we can assume len(s) == 0, so all buffer is read and chunk is not yet full
 	return l, nil
 }
@@ -376,8 +376,8 @@ func (self *Hasher) Write(b []byte) (int, error) {
 // ReadFrom reads from io.Reader and appends to the data to hash using Write
 // it reads so that chunk to hash is maximum length or reader reaches EOF
 // caller must Reset the hasher prior to call
-func (self *Hasher) ReadFrom(r io.Reader) (m int64, err error) {
-	bufsize := self.size*self.count - self.size*self.cur - len(self.segment)
+func (h *Hasher) ReadFrom(r io.Reader) (m int64, err error) {
+	bufsize := h.size*h.count - h.size*h.cur - len(h.segment)
 	buf := make([]byte, bufsize)
 	var read int
 	for {
@@ -385,7 +385,7 @@ func (self *Hasher) ReadFrom(r io.Reader) (m int64, err error) {
 		n, err = r.Read(buf)
 		read += n
 		if err == io.EOF || read == len(buf) {
-			hash := self.Sum(buf[:n])
+			hash := h.Sum(buf[:n])
 			if read == len(buf) {
 				err = NewEOC(hash)
 			}
@@ -394,7 +394,7 @@ func (self *Hasher) ReadFrom(r io.Reader) (m int64, err error) {
 		if err != nil {
 			break
 		}
-		n, err = self.Write(buf[:n])
+		n, err = h.Write(buf[:n])
 		if err != nil {
 			break
 		}
@@ -403,9 +403,9 @@ func (self *Hasher) ReadFrom(r io.Reader) (m int64, err error) {
 }
 
 // Reset needs to be called before writing to the hasher
-func (self *Hasher) Reset() {
-	self.getTree()
-	self.blockLength = nil
+func (h *Hasher) Reset() {
+	h.getTree()
+	h.blockLength = nil
 }
 
 // Hasher implements the SwarmHash interface
@@ -413,52 +413,52 @@ func (self *Hasher) Reset() {
 // ResetWithLength needs to be called before writing to the hasher
 // the argument is supposed to be the byte slice binary representation of
 // the length of the data subsumed under the hash
-func (self *Hasher) ResetWithLength(l []byte) {
-	self.Reset()
-	self.blockLength = l
+func (h *Hasher) ResetWithLength(l []byte) {
+	h.Reset()
+	h.blockLength = l
 }
 
 // Release gives back the Tree to the pool whereby it unlocks
 // it resets tree, segment and index
-func (self *Hasher) releaseTree() {
-	if self.bmt != nil {
-		n := self.bmt.leaves[self.cur]
+func (h *Hasher) releaseTree() {
+	if h.bmt != nil {
+		n := h.bmt.leaves[h.cur]
 		for ; n != nil; n = n.parent {
 			n.unbalanced = false
 			if n.parent != nil {
 				n.root = false
 			}
 		}
-		self.pool.Release(self.bmt)
-		self.bmt = nil
+		h.pool.Release(h.bmt)
+		h.bmt = nil
 
 	}
-	self.cur = 0
-	self.segment = nil
+	h.cur = 0
+	h.segment = nil
 }
 
-func (self *Hasher) writeSegment(i int, s []byte, d int) {
-	h := self.pool.hasher()
-	n := self.bmt.leaves[i]
+func (h *Hasher) writeSegment(i int, s []byte, d int) {
+	hash := h.pool.hasher()
+	n := h.bmt.leaves[i]
 
-	if len(s) > self.size && n.parent != nil {
+	if len(s) > h.size && n.parent != nil {
 		go func() {
-			h.Reset()
-			h.Write(s)
-			s = h.Sum(nil)
+			hash.Reset()
+			hash.Write(s)
+			s = hash.Sum(nil)
 
 			if n.root {
-				self.result <- s
+				h.result <- s
 				return
 			}
-			self.run(n.parent, h, d, n.index, s)
+			h.run(n.parent, hash, d, n.index, s)
 		}()
 		return
 	}
-	go self.run(n, h, d, i*2, s)
+	go h.run(n, hash, d, i*2, s)
 }
 
-func (self *Hasher) run(n *Node, h hash.Hash, d int, i int, s []byte) {
+func (h *Hasher) run(n *Node, hash hash.Hash, d int, i int, s []byte) {
 	isLeft := i%2 == 0
 	for {
 		if isLeft {
@@ -470,18 +470,18 @@ func (self *Hasher) run(n *Node, h hash.Hash, d int, i int, s []byte) {
 			return
 		}
 		if !n.unbalanced || !isLeft || i == 0 && d == 0 {
-			h.Reset()
-			h.Write(n.left)
-			h.Write(n.right)
-			s = h.Sum(nil)
+			hash.Reset()
+			hash.Write(n.left)
+			hash.Write(n.right)
+			s = hash.Sum(nil)
 
 		} else {
 			s = append(n.left, n.right...)
 		}
 
-		self.hash = s
+		h.hash = s
 		if n.root {
-			self.result <- s
+			h.result <- s
 			return
 		}
 
@@ -492,20 +492,20 @@ func (self *Hasher) run(n *Node, h hash.Hash, d int, i int, s []byte) {
 }
 
 // getTree obtains a BMT resource by reserving one from the pool
-func (self *Hasher) getTree() *Tree {
-	if self.bmt != nil {
-		return self.bmt
+func (h *Hasher) getTree() *Tree {
+	if h.bmt != nil {
+		return h.bmt
 	}
-	t := self.pool.Reserve()
-	self.bmt = t
+	t := h.pool.Reserve()
+	h.bmt = t
 	return t
 }
 
 // atomic bool toggle implementing a concurrent reusable 2-state object
 // atomic addint with %2 implements atomic bool toggle
 // it returns true if the toggler just put it in the active/waiting state
-func (self *Node) toggle() bool {
-	return atomic.AddInt32(&self.state, 1)%2 == 1
+func (n *Node) toggle() bool {
+	return atomic.AddInt32(&n.state, 1)%2 == 1
 }
 
 func hashstr(b []byte) string {
@@ -525,7 +525,7 @@ func depth(n int) (d int) {
 
 // finalise is following the zigzags on the tree belonging
 // to the final datasegment
-func (self *Hasher) finalise(n *Node, i int) (d int) {
+func (h *Hasher) finalise(n *Node, i int) (d int) {
 	isLeft := i%2 == 0
 	for {
 		// when the final segment's path is going via left segments
@@ -550,8 +550,8 @@ type EOC struct {
 }
 
 // Error returns the error string
-func (self *EOC) Error() string {
-	return fmt.Sprintf("hasher limit reached, chunk hash: %x", self.Hash)
+func (e *EOC) Error() string {
+	return fmt.Sprintf("hasher limit reached, chunk hash: %x", e.Hash)
 }
 
 // NewEOC creates new end of chunk error with the hash
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/api.go b/eth/filters/api.go
index ec403709c5..1297b74788 100644
--- a/eth/filters/api.go
+++ b/eth/filters/api.go
@@ -268,14 +268,8 @@ func (api *PublicFilterAPI) Logs(ctx context.Context, crit FilterCriteria) (*rpc
 }
 
 // FilterCriteria represents a request to create a new filter.
-//
-// TODO(karalabe): Kill this in favor of ethereum.FilterQuery.
-type FilterCriteria struct {
-	FromBlock *big.Int
-	ToBlock   *big.Int
-	Addresses []common.Address
-	Topics    [][]common.Hash
-}
+// Same as ethereum.FilterQuery but with UnmarshalJSON() method.
+type FilterCriteria ethereum.FilterQuery
 
 // NewFilter creates a new filter and returns the filter id. It can be
 // used to retrieve logs when the state changes. This method cannot be
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 8efd7bf845..c57042920a 100644
--- a/ethdb/memory_database.go
+++ b/ethdb/memory_database.go
@@ -31,16 +31,16 @@ type MemDatabase struct {
 	lock sync.RWMutex
 }
 
-func NewMemDatabase() (*MemDatabase, error) {
+func NewMemDatabase() *MemDatabase {
 	return &MemDatabase{
 		db: make(map[string][]byte),
-	}, nil
+	}
 }
 
-func NewMemDatabaseWithCap(size int) (*MemDatabase, error) {
+func NewMemDatabaseWithCap(size int) *MemDatabase {
 	return &MemDatabase{
 		db: make(map[string][]byte, size),
-	}, nil
+	}
 }
 
 func (db *MemDatabase) Put(key []byte, value []byte) error {
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/event/feed.go b/event/feed.go
index 78fa3d98d8..f578f00c10 100644
--- a/event/feed.go
+++ b/event/feed.go
@@ -148,7 +148,9 @@ func (f *Feed) Send(value interface{}) (nsent int) {
 		f.sendCases[i].Send = rvalue
 	}
 
-	// Send until all channels except removeSub have been chosen.
+	// Send until all channels except removeSub have been chosen. 'cases' tracks a prefix
+	// of sendCases. When a send succeeds, the corresponding case moves to the end of
+	// 'cases' and it shrinks by one element.
 	cases := f.sendCases
 	for {
 		// Fast path: try sending without blocking before adding to the select set.
@@ -170,6 +172,7 @@ func (f *Feed) Send(value interface{}) (nsent int) {
 			index := f.sendCases.find(recv.Interface())
 			f.sendCases = f.sendCases.delete(index)
 			if index >= 0 && index < len(cases) {
+				// Shrink 'cases' too because the removed case was still active.
 				cases = f.sendCases[:len(cases)-1]
 			}
 		} else {
diff --git a/event/feed_test.go b/event/feed_test.go
index a82c103033..be8876932c 100644
--- a/event/feed_test.go
+++ b/event/feed_test.go
@@ -235,6 +235,45 @@ func TestFeedUnsubscribeBlockedPost(t *testing.T) {
 	wg.Wait()
 }
 
+// Checks that unsubscribing a channel during Send works even if that
+// channel has already been sent on.
+func TestFeedUnsubscribeSentChan(t *testing.T) {
+	var (
+		feed Feed
+		ch1  = make(chan int)
+		ch2  = make(chan int)
+		sub1 = feed.Subscribe(ch1)
+		sub2 = feed.Subscribe(ch2)
+		wg   sync.WaitGroup
+	)
+	defer sub2.Unsubscribe()
+
+	wg.Add(1)
+	go func() {
+		feed.Send(0)
+		wg.Done()
+	}()
+
+	// Wait for the value on ch1.
+	<-ch1
+	// Unsubscribe ch1, removing it from the send cases.
+	sub1.Unsubscribe()
+
+	// Receive ch2, finishing Send.
+	<-ch2
+	wg.Wait()
+
+	// Send again. This should send to ch2 only, so the wait group will unblock
+	// as soon as a value is received on ch2.
+	wg.Add(1)
+	go func() {
+		feed.Send(0)
+		wg.Done()
+	}()
+	<-ch2
+	wg.Wait()
+}
+
 func TestFeedUnsubscribeFromInbox(t *testing.T) {
 	var (
 		feed Feed
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/postprocess.go b/light/postprocess.go
index 8b9a029112..c06c18027e 100644
--- a/light/postprocess.go
+++ b/light/postprocess.go
@@ -59,18 +59,18 @@ type trustedCheckpoint struct {
 var (
 	mainnetCheckpoint = trustedCheckpoint{
 		name:          "mainnet",
-		sectionIdx:    165,
-		sectionHead:   common.HexToHash("21028acf9cd9ce80257221adc437c3c58ce046c4d43c21c3e9b1d1349059ec73"),
-		chtRoot:       common.HexToHash("26b2458cb7d0080d3a39311c914be92c368777a65ec074e1893b8bdc79e3910a"),
-		bloomTrieRoot: common.HexToHash("5d06908769179186165a72db7fc3473b25c28ed27efe78a392a9ff2c3fa67f84"),
+		sectionIdx:    170,
+		sectionHead:   common.HexToHash("3bb2c28bcce463d57968f14f56cdb3fbf35349ab7a701f44c1afb57349c9a356"),
+		chtRoot:       common.HexToHash("d92b6d0853455f8439086292338e87f69781921680dd7aa072fb71547b87415e"),
+		bloomTrieRoot: common.HexToHash("e4e8250a2fefddead7ae42daecd848cbf9b66d748a8270f8bbd4370b764bb9e9"),
 	}
 
 	ropstenCheckpoint = trustedCheckpoint{
 		name:          "ropsten",
-		sectionIdx:    92,
-		sectionHead:   common.HexToHash("21a158f9cc643da13a237cafceb37381072649f7278cf98c5820bfbced7cfcec"),
-		chtRoot:       common.HexToHash("1a8ddb8b086d7a33ca90eea90730225948fa504ae0283b15aff3c15c0e089bf9"),
-		bloomTrieRoot: common.HexToHash("fd192f92afbcdd0020c81ca0625116b5995509659653b10123bd986fe5129cc1"),
+		sectionIdx:    97,
+		sectionHead:   common.HexToHash("719448c67c01eb5b9f27833a36a4e34612f66801316d7ff37daf9e77fb4cd095"),
+		chtRoot:       common.HexToHash("a7857afc15930ca6e583b6c3d563a025144011655843d52d28e2fdaadd417bea"),
+		bloomTrieRoot: common.HexToHash("9c71d4b50cbec86dfeaa8e08992de8a4667b81d13c54d6522b17ce2fc5d36416"),
 	}
 )
 
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/discover/table_test.go b/p2p/discover/table_test.go
index 3ce48d2995..f2d3f9a2ad 100644
--- a/p2p/discover/table_test.go
+++ b/p2p/discover/table_test.go
@@ -582,26 +582,26 @@ func (*preminedTestnet) ping(toid NodeID, toaddr *net.UDPAddr) error { return ni
 
 // mine generates a testnet struct literal with nodes at
 // various distances to the given target.
-func (n *preminedTestnet) mine(target NodeID) {
-	n.target = target
-	n.targetSha = crypto.Keccak256Hash(n.target[:])
+func (tn *preminedTestnet) mine(target NodeID) {
+	tn.target = target
+	tn.targetSha = crypto.Keccak256Hash(tn.target[:])
 	found := 0
 	for found < bucketSize*10 {
 		k := newkey()
 		id := PubkeyID(&k.PublicKey)
 		sha := crypto.Keccak256Hash(id[:])
-		ld := logdist(n.targetSha, sha)
-		if len(n.dists[ld]) < bucketSize {
-			n.dists[ld] = append(n.dists[ld], id)
+		ld := logdist(tn.targetSha, sha)
+		if len(tn.dists[ld]) < bucketSize {
+			tn.dists[ld] = append(tn.dists[ld], id)
 			fmt.Println("found ID with ld", ld)
 			found++
 		}
 	}
 	fmt.Println("&preminedTestnet{")
-	fmt.Printf("	target: %#v,\n", n.target)
-	fmt.Printf("	targetSha: %#v,\n", n.targetSha)
-	fmt.Printf("	dists: [%d][]NodeID{\n", len(n.dists))
-	for ld, ns := range n.dists {
+	fmt.Printf("	target: %#v,\n", tn.target)
+	fmt.Printf("	targetSha: %#v,\n", tn.targetSha)
+	fmt.Printf("	dists: [%d][]NodeID{\n", len(tn.dists))
+	for ld, ns := range tn.dists {
 		if len(ns) == 0 {
 			continue
 		}
diff --git a/p2p/discv5/net_test.go b/p2p/discv5/net_test.go
index 369282ca9c..001d193cc9 100644
--- a/p2p/discv5/net_test.go
+++ b/p2p/discv5/net_test.go
@@ -336,26 +336,26 @@ func (*preminedTestnet) localAddr() *net.UDPAddr {
 
 // mine generates a testnet struct literal with nodes at
 // various distances to the given target.
-func (n *preminedTestnet) mine(target NodeID) {
-	n.target = target
-	n.targetSha = crypto.Keccak256Hash(n.target[:])
+func (tn *preminedTestnet) mine(target NodeID) {
+	tn.target = target
+	tn.targetSha = crypto.Keccak256Hash(tn.target[:])
 	found := 0
 	for found < bucketSize*10 {
 		k := newkey()
 		id := PubkeyID(&k.PublicKey)
 		sha := crypto.Keccak256Hash(id[:])
-		ld := logdist(n.targetSha, sha)
-		if len(n.dists[ld]) < bucketSize {
-			n.dists[ld] = append(n.dists[ld], id)
+		ld := logdist(tn.targetSha, sha)
+		if len(tn.dists[ld]) < bucketSize {
+			tn.dists[ld] = append(tn.dists[ld], id)
 			fmt.Println("found ID with ld", ld)
 			found++
 		}
 	}
 	fmt.Println("&preminedTestnet{")
-	fmt.Printf("	target: %#v,\n", n.target)
-	fmt.Printf("	targetSha: %#v,\n", n.targetSha)
-	fmt.Printf("	dists: [%d][]NodeID{\n", len(n.dists))
-	for ld, ns := range n.dists {
+	fmt.Printf("	target: %#v,\n", tn.target)
+	fmt.Printf("	targetSha: %#v,\n", tn.targetSha)
+	fmt.Printf("	dists: [%d][]NodeID{\n", len(tn.dists))
+	for ld, ns := range tn.dists {
 		if len(ns) == 0 {
 			continue
 		}
diff --git a/p2p/discv5/node.go b/p2p/discv5/node.go
index fd88a55b15..3d47485122 100644
--- a/p2p/discv5/node.go
+++ b/p2p/discv5/node.go
@@ -315,11 +315,11 @@ func PubkeyID(pub *ecdsa.PublicKey) NodeID {
 
 // Pubkey returns the public key represented by the node ID.
 // It returns an error if the ID is not a point on the curve.
-func (id NodeID) Pubkey() (*ecdsa.PublicKey, error) {
+func (n NodeID) Pubkey() (*ecdsa.PublicKey, error) {
 	p := &ecdsa.PublicKey{Curve: crypto.S256(), X: new(big.Int), Y: new(big.Int)}
-	half := len(id) / 2
-	p.X.SetBytes(id[:half])
-	p.Y.SetBytes(id[half:])
+	half := len(n) / 2
+	p.X.SetBytes(n[:half])
+	p.Y.SetBytes(n[half:])
 	if !p.Curve.IsOnCurve(p.X, p.Y) {
 		return nil, errors.New("id is invalid secp256k1 curve point")
 	}
diff --git a/p2p/discv5/ticket.go b/p2p/discv5/ticket.go
index b3d1ac4baf..ae4b18e7cd 100644
--- a/p2p/discv5/ticket.go
+++ b/p2p/discv5/ticket.go
@@ -304,8 +304,8 @@ func (s ticketRefByWaitTime) Len() int {
 	return len(s)
 }
 
-func (r ticketRef) waitTime() mclock.AbsTime {
-	return r.t.regTime[r.idx] - r.t.issueTime
+func (ref ticketRef) waitTime() mclock.AbsTime {
+	return ref.t.regTime[ref.idx] - ref.t.issueTime
 }
 
 // Less reports whether the element with
diff --git a/p2p/discv5/topic.go b/p2p/discv5/topic.go
index e7a7f8e02a..609a41297f 100644
--- a/p2p/discv5/topic.go
+++ b/p2p/discv5/topic.go
@@ -271,15 +271,15 @@ func (t *topicTable) useTicket(node *Node, serialNo uint32, topics []Topic, idx
 	return false
 }
 
-func (topictab *topicTable) getTicket(node *Node, topics []Topic) *ticket {
-	topictab.collectGarbage()
+func (t *topicTable) getTicket(node *Node, topics []Topic) *ticket {
+	t.collectGarbage()
 
 	now := mclock.Now()
-	n := topictab.getOrNewNode(node)
+	n := t.getOrNewNode(node)
 	n.lastIssuedTicket++
-	topictab.storeTicketCounters(node)
+	t.storeTicketCounters(node)
 
-	t := &ticket{
+	tic := &ticket{
 		issueTime: now,
 		topics:    topics,
 		serial:    n.lastIssuedTicket,
@@ -287,15 +287,15 @@ func (topictab *topicTable) getTicket(node *Node, topics []Topic) *ticket {
 	}
 	for i, topic := range topics {
 		var waitPeriod time.Duration
-		if topic := topictab.topics[topic]; topic != nil {
+		if topic := t.topics[topic]; topic != nil {
 			waitPeriod = topic.wcl.waitPeriod
 		} else {
 			waitPeriod = minWaitPeriod
 		}
 
-		t.regTime[i] = now + mclock.AbsTime(waitPeriod)
+		tic.regTime[i] = now + mclock.AbsTime(waitPeriod)
 	}
-	return t
+	return tic
 }
 
 const gcInterval = time.Minute
diff --git a/p2p/message.go b/p2p/message.go
index ffa2ef86a0..a4eac54d33 100644
--- a/p2p/message.go
+++ b/p2p/message.go
@@ -270,15 +270,15 @@ func newMsgEventer(rw MsgReadWriter, feed *event.Feed, peerID discover.NodeID, p
 
 // ReadMsg reads a message from the underlying MsgReadWriter and emits a
 // "message received" event
-func (self *msgEventer) ReadMsg() (Msg, error) {
-	msg, err := self.MsgReadWriter.ReadMsg()
+func (ev *msgEventer) ReadMsg() (Msg, error) {
+	msg, err := ev.MsgReadWriter.ReadMsg()
 	if err != nil {
 		return msg, err
 	}
-	self.feed.Send(&PeerEvent{
+	ev.feed.Send(&PeerEvent{
 		Type:     PeerEventTypeMsgRecv,
-		Peer:     self.peerID,
-		Protocol: self.Protocol,
+		Peer:     ev.peerID,
+		Protocol: ev.Protocol,
 		MsgCode:  &msg.Code,
 		MsgSize:  &msg.Size,
 	})
@@ -287,15 +287,15 @@ func (self *msgEventer) ReadMsg() (Msg, error) {
 
 // WriteMsg writes a message to the underlying MsgReadWriter and emits a
 // "message sent" event
-func (self *msgEventer) WriteMsg(msg Msg) error {
-	err := self.MsgReadWriter.WriteMsg(msg)
+func (ev *msgEventer) WriteMsg(msg Msg) error {
+	err := ev.MsgReadWriter.WriteMsg(msg)
 	if err != nil {
 		return err
 	}
-	self.feed.Send(&PeerEvent{
+	ev.feed.Send(&PeerEvent{
 		Type:     PeerEventTypeMsgSend,
-		Peer:     self.peerID,
-		Protocol: self.Protocol,
+		Peer:     ev.peerID,
+		Protocol: ev.Protocol,
 		MsgCode:  &msg.Code,
 		MsgSize:  &msg.Size,
 	})
@@ -304,8 +304,8 @@ func (self *msgEventer) WriteMsg(msg Msg) error {
 
 // Close closes the underlying MsgReadWriter if it implements the io.Closer
 // interface
-func (self *msgEventer) Close() error {
-	if v, ok := self.MsgReadWriter.(io.Closer); ok {
+func (ev *msgEventer) Close() error {
+	if v, ok := ev.MsgReadWriter.(io.Closer); ok {
 		return v.Close()
 	}
 	return 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/p2p/peer_error.go b/p2p/peer_error.go
index a1cddb707b..ab61bfef06 100644
--- a/p2p/peer_error.go
+++ b/p2p/peer_error.go
@@ -48,8 +48,8 @@ func newPeerError(code int, format string, v ...interface{}) *peerError {
 	return err
 }
 
-func (self *peerError) Error() string {
-	return self.message
+func (pe *peerError) Error() string {
+	return pe.message
 }
 
 var errProtocolReturned = errors.New("protocol returned")
diff --git a/p2p/simulations/adapters/exec.go b/p2p/simulations/adapters/exec.go
index a566fb27d8..f381c11596 100644
--- a/p2p/simulations/adapters/exec.go
+++ b/p2p/simulations/adapters/exec.go
@@ -17,7 +17,6 @@
 package adapters
 
 import (
-	"bufio"
 	"context"
 	"crypto/ecdsa"
 	"encoding/json"
@@ -29,7 +28,6 @@ import (
 	"os/exec"
 	"os/signal"
 	"path/filepath"
-	"regexp"
 	"strings"
 	"sync"
 	"syscall"
@@ -150,10 +148,6 @@ func (n *ExecNode) Client() (*rpc.Client, error) {
 	return n.client, nil
 }
 
-// wsAddrPattern is a regex used to read the WebSocket address from the node's
-// log
-var wsAddrPattern = regexp.MustCompile(`ws://[\d.:]+`)
-
 // Start exec's the node passing the ID and service as command line arguments
 // and the node config encoded as JSON in the _P2P_NODE_CONFIG environment
 // variable
@@ -196,23 +190,9 @@ func (n *ExecNode) Start(snapshots map[string][]byte) (err error) {
 	n.Cmd = cmd
 
 	// read the WebSocket address from the stderr logs
-	var wsAddr string
-	wsAddrC := make(chan string)
-	go func() {
-		s := bufio.NewScanner(stderrR)
-		for s.Scan() {
-			if strings.Contains(s.Text(), "WebSocket endpoint opened:") {
-				wsAddrC <- wsAddrPattern.FindString(s.Text())
-			}
-		}
-	}()
-	select {
-	case wsAddr = <-wsAddrC:
-		if wsAddr == "" {
-			return errors.New("failed to read WebSocket address from stderr")
-		}
-	case <-time.After(10 * time.Second):
-		return errors.New("timed out waiting for WebSocket address on stderr")
+	wsAddr, err := findWSAddr(stderrR, 10*time.Second)
+	if err != nil {
+		return fmt.Errorf("error getting WebSocket address: %s", err)
 	}
 
 	// create the RPC client and load the node info
diff --git a/p2p/simulations/adapters/inproc.go b/p2p/simulations/adapters/inproc.go
index 48d7c17301..6d90b4a9fc 100644
--- a/p2p/simulations/adapters/inproc.go
+++ b/p2p/simulations/adapters/inproc.go
@@ -154,30 +154,30 @@ type SimNode struct {
 }
 
 // Addr returns the node's discovery address
-func (self *SimNode) Addr() []byte {
-	return []byte(self.Node().String())
+func (sn *SimNode) Addr() []byte {
+	return []byte(sn.Node().String())
 }
 
 // Node returns a discover.Node representing the SimNode
-func (self *SimNode) Node() *discover.Node {
-	return discover.NewNode(self.ID, net.IP{127, 0, 0, 1}, 30303, 30303)
+func (sn *SimNode) Node() *discover.Node {
+	return discover.NewNode(sn.ID, net.IP{127, 0, 0, 1}, 30303, 30303)
 }
 
 // Client returns an rpc.Client which can be used to communicate with the
 // underlying services (it is set once the node has started)
-func (self *SimNode) Client() (*rpc.Client, error) {
-	self.lock.RLock()
-	defer self.lock.RUnlock()
-	if self.client == nil {
+func (sn *SimNode) Client() (*rpc.Client, error) {
+	sn.lock.RLock()
+	defer sn.lock.RUnlock()
+	if sn.client == nil {
 		return nil, errors.New("node not started")
 	}
-	return self.client, nil
+	return sn.client, nil
 }
 
 // ServeRPC serves RPC requests over the given connection by creating an
 // in-memory client to the node's RPC server
-func (self *SimNode) ServeRPC(conn net.Conn) error {
-	handler, err := self.node.RPCHandler()
+func (sn *SimNode) ServeRPC(conn net.Conn) error {
+	handler, err := sn.node.RPCHandler()
 	if err != nil {
 		return err
 	}
@@ -187,13 +187,13 @@ func (self *SimNode) ServeRPC(conn net.Conn) error {
 
 // Snapshots creates snapshots of the services by calling the
 // simulation_snapshot RPC method
-func (self *SimNode) Snapshots() (map[string][]byte, error) {
-	self.lock.RLock()
-	services := make(map[string]node.Service, len(self.running))
-	for name, service := range self.running {
+func (sn *SimNode) Snapshots() (map[string][]byte, error) {
+	sn.lock.RLock()
+	services := make(map[string]node.Service, len(sn.running))
+	for name, service := range sn.running {
 		services[name] = service
 	}
-	self.lock.RUnlock()
+	sn.lock.RUnlock()
 	if len(services) == 0 {
 		return nil, errors.New("no running services")
 	}
@@ -213,23 +213,23 @@ func (self *SimNode) Snapshots() (map[string][]byte, error) {
 }
 
 // Start registers the services and starts the underlying devp2p node
-func (self *SimNode) Start(snapshots map[string][]byte) error {
+func (sn *SimNode) Start(snapshots map[string][]byte) error {
 	newService := func(name string) func(ctx *node.ServiceContext) (node.Service, error) {
 		return func(nodeCtx *node.ServiceContext) (node.Service, error) {
 			ctx := &ServiceContext{
-				RPCDialer:   self.adapter,
+				RPCDialer:   sn.adapter,
 				NodeContext: nodeCtx,
-				Config:      self.config,
+				Config:      sn.config,
 			}
 			if snapshots != nil {
 				ctx.Snapshot = snapshots[name]
 			}
-			serviceFunc := self.adapter.services[name]
+			serviceFunc := sn.adapter.services[name]
 			service, err := serviceFunc(ctx)
 			if err != nil {
 				return nil, err
 			}
-			self.running[name] = service
+			sn.running[name] = service
 			return service, nil
 		}
 	}
@@ -237,9 +237,9 @@ func (self *SimNode) Start(snapshots map[string][]byte) error {
 	// ensure we only register the services once in the case of the node
 	// being stopped and then started again
 	var regErr error
-	self.registerOnce.Do(func() {
-		for _, name := range self.config.Services {
-			if err := self.node.Register(newService(name)); err != nil {
+	sn.registerOnce.Do(func() {
+		for _, name := range sn.config.Services {
+			if err := sn.node.Register(newService(name)); err != nil {
 				regErr = err
 				return
 			}
@@ -249,54 +249,54 @@ func (self *SimNode) Start(snapshots map[string][]byte) error {
 		return regErr
 	}
 
-	if err := self.node.Start(); err != nil {
+	if err := sn.node.Start(); err != nil {
 		return err
 	}
 
 	// create an in-process RPC client
-	handler, err := self.node.RPCHandler()
+	handler, err := sn.node.RPCHandler()
 	if err != nil {
 		return err
 	}
 
-	self.lock.Lock()
-	self.client = rpc.DialInProc(handler)
-	self.lock.Unlock()
+	sn.lock.Lock()
+	sn.client = rpc.DialInProc(handler)
+	sn.lock.Unlock()
 
 	return nil
 }
 
 // Stop closes the RPC client and stops the underlying devp2p node
-func (self *SimNode) Stop() error {
-	self.lock.Lock()
-	if self.client != nil {
-		self.client.Close()
-		self.client = nil
+func (sn *SimNode) Stop() error {
+	sn.lock.Lock()
+	if sn.client != nil {
+		sn.client.Close()
+		sn.client = nil
 	}
-	self.lock.Unlock()
-	return self.node.Stop()
+	sn.lock.Unlock()
+	return sn.node.Stop()
 }
 
 // Services returns a copy of the underlying services
-func (self *SimNode) Services() []node.Service {
-	self.lock.RLock()
-	defer self.lock.RUnlock()
-	services := make([]node.Service, 0, len(self.running))
-	for _, service := range self.running {
+func (sn *SimNode) Services() []node.Service {
+	sn.lock.RLock()
+	defer sn.lock.RUnlock()
+	services := make([]node.Service, 0, len(sn.running))
+	for _, service := range sn.running {
 		services = append(services, service)
 	}
 	return services
 }
 
 // Server returns the underlying p2p.Server
-func (self *SimNode) Server() *p2p.Server {
-	return self.node.Server()
+func (sn *SimNode) Server() *p2p.Server {
+	return sn.node.Server()
 }
 
 // SubscribeEvents subscribes the given channel to peer events from the
 // underlying p2p.Server
-func (self *SimNode) SubscribeEvents(ch chan *p2p.PeerEvent) event.Subscription {
-	srv := self.Server()
+func (sn *SimNode) SubscribeEvents(ch chan *p2p.PeerEvent) event.Subscription {
+	srv := sn.Server()
 	if srv == nil {
 		panic("node not running")
 	}
@@ -304,12 +304,12 @@ func (self *SimNode) SubscribeEvents(ch chan *p2p.PeerEvent) event.Subscription
 }
 
 // NodeInfo returns information about the node
-func (self *SimNode) NodeInfo() *p2p.NodeInfo {
-	server := self.Server()
+func (sn *SimNode) NodeInfo() *p2p.NodeInfo {
+	server := sn.Server()
 	if server == nil {
 		return &p2p.NodeInfo{
-			ID:    self.ID.String(),
-			Enode: self.Node().String(),
+			ID:    sn.ID.String(),
+			Enode: sn.Node().String(),
 		}
 	}
 	return server.NodeInfo()
diff --git a/p2p/simulations/adapters/state.go b/p2p/simulations/adapters/state.go
index 0d4ecfb0ff..78dfb11f95 100644
--- a/p2p/simulations/adapters/state.go
+++ b/p2p/simulations/adapters/state.go
@@ -20,12 +20,12 @@ type SimStateStore struct {
 	m map[string][]byte
 }
 
-func (self *SimStateStore) Load(s string) ([]byte, error) {
-	return self.m[s], nil
+func (st *SimStateStore) Load(s string) ([]byte, error) {
+	return st.m[s], nil
 }
 
-func (self *SimStateStore) Save(s string, data []byte) error {
-	self.m[s] = data
+func (st *SimStateStore) Save(s string, data []byte) error {
+	st.m[s] = data
 	return nil
 }
 
diff --git a/p2p/simulations/adapters/ws.go b/p2p/simulations/adapters/ws.go
new file mode 100644
index 0000000000..979a21709e
--- /dev/null
+++ b/p2p/simulations/adapters/ws.go
@@ -0,0 +1,51 @@
+package adapters
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"regexp"
+	"strings"
+	"time"
+)
+
+// wsAddrPattern is a regex used to read the WebSocket address from the node's
+// log
+var wsAddrPattern = regexp.MustCompile(`ws://[\d.:]+`)
+
+func matchWSAddr(str string) (string, bool) {
+	if !strings.Contains(str, "WebSocket endpoint opened") {
+		return "", false
+	}
+
+	return wsAddrPattern.FindString(str), true
+}
+
+// findWSAddr scans through reader r, looking for the log entry with
+// WebSocket address information.
+func findWSAddr(r io.Reader, timeout time.Duration) (string, error) {
+	ch := make(chan string)
+
+	go func() {
+		s := bufio.NewScanner(r)
+		for s.Scan() {
+			addr, ok := matchWSAddr(s.Text())
+			if ok {
+				ch <- addr
+			}
+		}
+		close(ch)
+	}()
+
+	var wsAddr string
+	select {
+	case wsAddr = <-ch:
+		if wsAddr == "" {
+			return "", errors.New("empty result")
+		}
+	case <-time.After(timeout):
+		return "", errors.New("timed out")
+	}
+
+	return wsAddr, nil
+}
diff --git a/p2p/simulations/adapters/ws_test.go b/p2p/simulations/adapters/ws_test.go
new file mode 100644
index 0000000000..0bb9ed2b2b
--- /dev/null
+++ b/p2p/simulations/adapters/ws_test.go
@@ -0,0 +1,21 @@
+package adapters
+
+import (
+	"bytes"
+	"testing"
+	"time"
+)
+
+func TestFindWSAddr(t *testing.T) {
+	line := `t=2018-05-02T19:00:45+0200 lvl=info msg="WebSocket endpoint opened"  node.id=26c65a606d1125a44695bc08573190d047152b6b9a776ccbbe593e90f91444d9c1ebdadac6a775ad9fdd0923468a1d698ed3a842c1fb89c1bc0f9d4801f8c39c url=ws://127.0.0.1:59975`
+	buf := bytes.NewBufferString(line)
+	got, err := findWSAddr(buf, 10*time.Second)
+	if err != nil {
+		t.Fatalf("Failed to find addr: %v", err)
+	}
+	expected := `ws://127.0.0.1:59975`
+
+	if got != expected {
+		t.Fatalf("Expected to get '%s', but got '%s'", expected, got)
+	}
+}
diff --git a/p2p/simulations/network.go b/p2p/simulations/network.go
index 0983e0a85a..1a2c1e8ff4 100644
--- a/p2p/simulations/network.go
+++ b/p2p/simulations/network.go
@@ -74,22 +74,22 @@ func NewNetwork(nodeAdapter adapters.NodeAdapter, conf *NetworkConfig) *Network
 }
 
 // Events returns the output event feed of the Network.
-func (self *Network) Events() *event.Feed {
-	return &self.events
+func (net *Network) Events() *event.Feed {
+	return &net.events
 }
 
 // NewNode adds a new node to the network with a random ID
-func (self *Network) NewNode() (*Node, error) {
+func (net *Network) NewNode() (*Node, error) {
 	conf := adapters.RandomNodeConfig()
-	conf.Services = []string{self.DefaultService}
-	return self.NewNodeWithConfig(conf)
+	conf.Services = []string{net.DefaultService}
+	return net.NewNodeWithConfig(conf)
 }
 
 // NewNodeWithConfig adds a new node to the network with the given config,
 // returning an error if a node with the same ID or name already exists
-func (self *Network) NewNodeWithConfig(conf *adapters.NodeConfig) (*Node, error) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
+func (net *Network) NewNodeWithConfig(conf *adapters.NodeConfig) (*Node, error) {
+	net.lock.Lock()
+	defer net.lock.Unlock()
 
 	// create a random ID and PrivateKey if not set
 	if conf.ID == (discover.NodeID{}) {
@@ -100,31 +100,31 @@ func (self *Network) NewNodeWithConfig(conf *adapters.NodeConfig) (*Node, error)
 	id := conf.ID
 	if conf.Reachable == nil {
 		conf.Reachable = func(otherID discover.NodeID) bool {
-			_, err := self.InitConn(conf.ID, otherID)
+			_, err := net.InitConn(conf.ID, otherID)
 			return err == nil
 		}
 	}
 
 	// assign a name to the node if not set
 	if conf.Name == "" {
-		conf.Name = fmt.Sprintf("node%02d", len(self.Nodes)+1)
+		conf.Name = fmt.Sprintf("node%02d", len(net.Nodes)+1)
 	}
 
 	// check the node doesn't already exist
-	if node := self.getNode(id); node != nil {
+	if node := net.getNode(id); node != nil {
 		return nil, fmt.Errorf("node with ID %q already exists", id)
 	}
-	if node := self.getNodeByName(conf.Name); node != nil {
+	if node := net.getNodeByName(conf.Name); node != nil {
 		return nil, fmt.Errorf("node with name %q already exists", conf.Name)
 	}
 
 	// if no services are configured, use the default service
 	if len(conf.Services) == 0 {
-		conf.Services = []string{self.DefaultService}
+		conf.Services = []string{net.DefaultService}
 	}
 
 	// use the NodeAdapter to create the node
-	adapterNode, err := self.nodeAdapter.NewNode(conf)
+	adapterNode, err := net.nodeAdapter.NewNode(conf)
 	if err != nil {
 		return nil, err
 	}
@@ -133,27 +133,27 @@ func (self *Network) NewNodeWithConfig(conf *adapters.NodeConfig) (*Node, error)
 		Config: conf,
 	}
 	log.Trace(fmt.Sprintf("node %v created", id))
-	self.nodeMap[id] = len(self.Nodes)
-	self.Nodes = append(self.Nodes, node)
+	net.nodeMap[id] = len(net.Nodes)
+	net.Nodes = append(net.Nodes, node)
 
 	// emit a "control" event
-	self.events.Send(ControlEvent(node))
+	net.events.Send(ControlEvent(node))
 
 	return node, nil
 }
 
 // Config returns the network configuration
-func (self *Network) Config() *NetworkConfig {
-	return &self.NetworkConfig
+func (net *Network) Config() *NetworkConfig {
+	return &net.NetworkConfig
 }
 
 // StartAll starts all nodes in the network
-func (self *Network) StartAll() error {
-	for _, node := range self.Nodes {
+func (net *Network) StartAll() error {
+	for _, node := range net.Nodes {
 		if node.Up {
 			continue
 		}
-		if err := self.Start(node.ID()); err != nil {
+		if err := net.Start(node.ID()); err != nil {
 			return err
 		}
 	}
@@ -161,12 +161,12 @@ func (self *Network) StartAll() error {
 }
 
 // StopAll stops all nodes in the network
-func (self *Network) StopAll() error {
-	for _, node := range self.Nodes {
+func (net *Network) StopAll() error {
+	for _, node := range net.Nodes {
 		if !node.Up {
 			continue
 		}
-		if err := self.Stop(node.ID()); err != nil {
+		if err := net.Stop(node.ID()); err != nil {
 			return err
 		}
 	}
@@ -174,21 +174,21 @@ func (self *Network) StopAll() error {
 }
 
 // Start starts the node with the given ID
-func (self *Network) Start(id discover.NodeID) error {
-	return self.startWithSnapshots(id, nil)
+func (net *Network) Start(id discover.NodeID) error {
+	return net.startWithSnapshots(id, nil)
 }
 
 // startWithSnapshots starts the node with the given ID using the give
 // snapshots
-func (self *Network) startWithSnapshots(id discover.NodeID, snapshots map[string][]byte) error {
-	node := self.GetNode(id)
+func (net *Network) startWithSnapshots(id discover.NodeID, snapshots map[string][]byte) error {
+	node := net.GetNode(id)
 	if node == nil {
 		return fmt.Errorf("node %v does not exist", id)
 	}
 	if node.Up {
 		return fmt.Errorf("node %v already up", id)
 	}
-	log.Trace(fmt.Sprintf("starting node %v: %v using %v", id, node.Up, self.nodeAdapter.Name()))
+	log.Trace(fmt.Sprintf("starting node %v: %v using %v", id, node.Up, net.nodeAdapter.Name()))
 	if err := node.Start(snapshots); err != nil {
 		log.Warn(fmt.Sprintf("start up failed: %v", err))
 		return err
@@ -196,7 +196,7 @@ func (self *Network) startWithSnapshots(id discover.NodeID, snapshots map[string
 	node.Up = true
 	log.Info(fmt.Sprintf("started node %v: %v", id, node.Up))
 
-	self.events.Send(NewEvent(node))
+	net.events.Send(NewEvent(node))
 
 	// subscribe to peer events
 	client, err := node.Client()
@@ -208,22 +208,22 @@ func (self *Network) startWithSnapshots(id discover.NodeID, snapshots map[string
 	if err != nil {
 		return fmt.Errorf("error getting peer events for node %v: %s", id, err)
 	}
-	go self.watchPeerEvents(id, events, sub)
+	go net.watchPeerEvents(id, events, sub)
 	return nil
 }
 
 // watchPeerEvents reads peer events from the given channel and emits
 // corresponding network events
-func (self *Network) watchPeerEvents(id discover.NodeID, events chan *p2p.PeerEvent, sub event.Subscription) {
+func (net *Network) watchPeerEvents(id discover.NodeID, events chan *p2p.PeerEvent, sub event.Subscription) {
 	defer func() {
 		sub.Unsubscribe()
 
 		// assume the node is now down
-		self.lock.Lock()
-		node := self.getNode(id)
+		net.lock.Lock()
+		node := net.getNode(id)
 		node.Up = false
-		self.lock.Unlock()
-		self.events.Send(NewEvent(node))
+		net.lock.Unlock()
+		net.events.Send(NewEvent(node))
 	}()
 	for {
 		select {
@@ -235,16 +235,16 @@ func (self *Network) watchPeerEvents(id discover.NodeID, events chan *p2p.PeerEv
 			switch event.Type {
 
 			case p2p.PeerEventTypeAdd:
-				self.DidConnect(id, peer)
+				net.DidConnect(id, peer)
 
 			case p2p.PeerEventTypeDrop:
-				self.DidDisconnect(id, peer)
+				net.DidDisconnect(id, peer)
 
 			case p2p.PeerEventTypeMsgSend:
-				self.DidSend(id, peer, event.Protocol, *event.MsgCode)
+				net.DidSend(id, peer, event.Protocol, *event.MsgCode)
 
 			case p2p.PeerEventTypeMsgRecv:
-				self.DidReceive(peer, id, event.Protocol, *event.MsgCode)
+				net.DidReceive(peer, id, event.Protocol, *event.MsgCode)
 
 			}
 
@@ -258,8 +258,8 @@ func (self *Network) watchPeerEvents(id discover.NodeID, events chan *p2p.PeerEv
 }
 
 // Stop stops the node with the given ID
-func (self *Network) Stop(id discover.NodeID) error {
-	node := self.GetNode(id)
+func (net *Network) Stop(id discover.NodeID) error {
+	node := net.GetNode(id)
 	if node == nil {
 		return fmt.Errorf("node %v does not exist", id)
 	}
@@ -272,15 +272,15 @@ func (self *Network) Stop(id discover.NodeID) error {
 	node.Up = false
 	log.Info(fmt.Sprintf("stop node %v: %v", id, node.Up))
 
-	self.events.Send(ControlEvent(node))
+	net.events.Send(ControlEvent(node))
 	return nil
 }
 
 // Connect connects two nodes together by calling the "admin_addPeer" RPC
 // method on the "one" node so that it connects to the "other" node
-func (self *Network) Connect(oneID, otherID discover.NodeID) error {
+func (net *Network) Connect(oneID, otherID discover.NodeID) error {
 	log.Debug(fmt.Sprintf("connecting %s to %s", oneID, otherID))
-	conn, err := self.InitConn(oneID, otherID)
+	conn, err := net.InitConn(oneID, otherID)
 	if err != nil {
 		return err
 	}
@@ -288,14 +288,14 @@ func (self *Network) Connect(oneID, otherID discover.NodeID) error {
 	if err != nil {
 		return err
 	}
-	self.events.Send(ControlEvent(conn))
+	net.events.Send(ControlEvent(conn))
 	return client.Call(nil, "admin_addPeer", string(conn.other.Addr()))
 }
 
 // Disconnect disconnects two nodes by calling the "admin_removePeer" RPC
 // method on the "one" node so that it disconnects from the "other" node
-func (self *Network) Disconnect(oneID, otherID discover.NodeID) error {
-	conn := self.GetConn(oneID, otherID)
+func (net *Network) Disconnect(oneID, otherID discover.NodeID) error {
+	conn := net.GetConn(oneID, otherID)
 	if conn == nil {
 		return fmt.Errorf("connection between %v and %v does not exist", oneID, otherID)
 	}
@@ -306,13 +306,13 @@ func (self *Network) Disconnect(oneID, otherID discover.NodeID) error {
 	if err != nil {
 		return err
 	}
-	self.events.Send(ControlEvent(conn))
+	net.events.Send(ControlEvent(conn))
 	return client.Call(nil, "admin_removePeer", string(conn.other.Addr()))
 }
 
 // DidConnect tracks the fact that the "one" node connected to the "other" node
-func (self *Network) DidConnect(one, other discover.NodeID) error {
-	conn, err := self.GetOrCreateConn(one, other)
+func (net *Network) DidConnect(one, other discover.NodeID) error {
+	conn, err := net.GetOrCreateConn(one, other)
 	if err != nil {
 		return fmt.Errorf("connection between %v and %v does not exist", one, other)
 	}
@@ -320,14 +320,14 @@ func (self *Network) DidConnect(one, other discover.NodeID) error {
 		return fmt.Errorf("%v and %v already connected", one, other)
 	}
 	conn.Up = true
-	self.events.Send(NewEvent(conn))
+	net.events.Send(NewEvent(conn))
 	return nil
 }
 
 // DidDisconnect tracks the fact that the "one" node disconnected from the
 // "other" node
-func (self *Network) DidDisconnect(one, other discover.NodeID) error {
-	conn := self.GetConn(one, other)
+func (net *Network) DidDisconnect(one, other discover.NodeID) error {
+	conn := net.GetConn(one, other)
 	if conn == nil {
 		return fmt.Errorf("connection between %v and %v does not exist", one, other)
 	}
@@ -336,12 +336,12 @@ func (self *Network) DidDisconnect(one, other discover.NodeID) error {
 	}
 	conn.Up = false
 	conn.initiated = time.Now().Add(-dialBanTimeout)
-	self.events.Send(NewEvent(conn))
+	net.events.Send(NewEvent(conn))
 	return nil
 }
 
 // DidSend tracks the fact that "sender" sent a message to "receiver"
-func (self *Network) DidSend(sender, receiver discover.NodeID, proto string, code uint64) error {
+func (net *Network) DidSend(sender, receiver discover.NodeID, proto string, code uint64) error {
 	msg := &Msg{
 		One:      sender,
 		Other:    receiver,
@@ -349,12 +349,12 @@ func (self *Network) DidSend(sender, receiver discover.NodeID, proto string, cod
 		Code:     code,
 		Received: false,
 	}
-	self.events.Send(NewEvent(msg))
+	net.events.Send(NewEvent(msg))
 	return nil
 }
 
 // DidReceive tracks the fact that "receiver" received a message from "sender"
-func (self *Network) DidReceive(sender, receiver discover.NodeID, proto string, code uint64) error {
+func (net *Network) DidReceive(sender, receiver discover.NodeID, proto string, code uint64) error {
 	msg := &Msg{
 		One:      sender,
 		Other:    receiver,
@@ -362,36 +362,36 @@ func (self *Network) DidReceive(sender, receiver discover.NodeID, proto string,
 		Code:     code,
 		Received: true,
 	}
-	self.events.Send(NewEvent(msg))
+	net.events.Send(NewEvent(msg))
 	return nil
 }
 
 // GetNode gets the node with the given ID, returning nil if the node does not
 // exist
-func (self *Network) GetNode(id discover.NodeID) *Node {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	return self.getNode(id)
+func (net *Network) GetNode(id discover.NodeID) *Node {
+	net.lock.Lock()
+	defer net.lock.Unlock()
+	return net.getNode(id)
 }
 
 // GetNode gets the node with the given name, returning nil if the node does
 // not exist
-func (self *Network) GetNodeByName(name string) *Node {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	return self.getNodeByName(name)
+func (net *Network) GetNodeByName(name string) *Node {
+	net.lock.Lock()
+	defer net.lock.Unlock()
+	return net.getNodeByName(name)
 }
 
-func (self *Network) getNode(id discover.NodeID) *Node {
-	i, found := self.nodeMap[id]
+func (net *Network) getNode(id discover.NodeID) *Node {
+	i, found := net.nodeMap[id]
 	if !found {
 		return nil
 	}
-	return self.Nodes[i]
+	return net.Nodes[i]
 }
 
-func (self *Network) getNodeByName(name string) *Node {
-	for _, node := range self.Nodes {
+func (net *Network) getNodeByName(name string) *Node {
+	for _, node := range net.Nodes {
 		if node.Config.Name == name {
 			return node
 		}
@@ -400,40 +400,40 @@ func (self *Network) getNodeByName(name string) *Node {
 }
 
 // GetNodes returns the existing nodes
-func (self *Network) GetNodes() (nodes []*Node) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
+func (net *Network) GetNodes() (nodes []*Node) {
+	net.lock.Lock()
+	defer net.lock.Unlock()
 
-	nodes = append(nodes, self.Nodes...)
+	nodes = append(nodes, net.Nodes...)
 	return nodes
 }
 
 // GetConn returns the connection which exists between "one" and "other"
 // regardless of which node initiated the connection
-func (self *Network) GetConn(oneID, otherID discover.NodeID) *Conn {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	return self.getConn(oneID, otherID)
+func (net *Network) GetConn(oneID, otherID discover.NodeID) *Conn {
+	net.lock.Lock()
+	defer net.lock.Unlock()
+	return net.getConn(oneID, otherID)
 }
 
 // GetOrCreateConn is like GetConn but creates the connection if it doesn't
 // already exist
-func (self *Network) GetOrCreateConn(oneID, otherID discover.NodeID) (*Conn, error) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	return self.getOrCreateConn(oneID, otherID)
+func (net *Network) GetOrCreateConn(oneID, otherID discover.NodeID) (*Conn, error) {
+	net.lock.Lock()
+	defer net.lock.Unlock()
+	return net.getOrCreateConn(oneID, otherID)
 }
 
-func (self *Network) getOrCreateConn(oneID, otherID discover.NodeID) (*Conn, error) {
-	if conn := self.getConn(oneID, otherID); conn != nil {
+func (net *Network) getOrCreateConn(oneID, otherID discover.NodeID) (*Conn, error) {
+	if conn := net.getConn(oneID, otherID); conn != nil {
 		return conn, nil
 	}
 
-	one := self.getNode(oneID)
+	one := net.getNode(oneID)
 	if one == nil {
 		return nil, fmt.Errorf("node %v does not exist", oneID)
 	}
-	other := self.getNode(otherID)
+	other := net.getNode(otherID)
 	if other == nil {
 		return nil, fmt.Errorf("node %v does not exist", otherID)
 	}
@@ -444,18 +444,18 @@ func (self *Network) getOrCreateConn(oneID, otherID discover.NodeID) (*Conn, err
 		other: other,
 	}
 	label := ConnLabel(oneID, otherID)
-	self.connMap[label] = len(self.Conns)
-	self.Conns = append(self.Conns, conn)
+	net.connMap[label] = len(net.Conns)
+	net.Conns = append(net.Conns, conn)
 	return conn, nil
 }
 
-func (self *Network) getConn(oneID, otherID discover.NodeID) *Conn {
+func (net *Network) getConn(oneID, otherID discover.NodeID) *Conn {
 	label := ConnLabel(oneID, otherID)
-	i, found := self.connMap[label]
+	i, found := net.connMap[label]
 	if !found {
 		return nil
 	}
-	return self.Conns[i]
+	return net.Conns[i]
 }
 
 // InitConn(one, other) retrieves the connectiton model for the connection between
@@ -466,13 +466,13 @@ func (self *Network) getConn(oneID, otherID discover.NodeID) *Conn {
 // it also checks whether there has been recent attempt to connect the peers
 // this is cheating as the simulation is used as an oracle and know about
 // remote peers attempt to connect to a node which will then not initiate the connection
-func (self *Network) InitConn(oneID, otherID discover.NodeID) (*Conn, error) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
+func (net *Network) InitConn(oneID, otherID discover.NodeID) (*Conn, error) {
+	net.lock.Lock()
+	defer net.lock.Unlock()
 	if oneID == otherID {
 		return nil, fmt.Errorf("refusing to connect to self %v", oneID)
 	}
-	conn, err := self.getOrCreateConn(oneID, otherID)
+	conn, err := net.getOrCreateConn(oneID, otherID)
 	if err != nil {
 		return nil, err
 	}
@@ -491,28 +491,28 @@ func (self *Network) InitConn(oneID, otherID discover.NodeID) (*Conn, error) {
 }
 
 // Shutdown stops all nodes in the network and closes the quit channel
-func (self *Network) Shutdown() {
-	for _, node := range self.Nodes {
+func (net *Network) Shutdown() {
+	for _, node := range net.Nodes {
 		log.Debug(fmt.Sprintf("stopping node %s", node.ID().TerminalString()))
 		if err := node.Stop(); err != nil {
 			log.Warn(fmt.Sprintf("error stopping node %s", node.ID().TerminalString()), "err", err)
 		}
 	}
-	close(self.quitc)
+	close(net.quitc)
 }
 
 //Reset resets all network properties:
 //emtpies the nodes and the connection list
-func (self *Network) Reset() {
-	self.lock.Lock()
-	defer self.lock.Unlock()
+func (net *Network) Reset() {
+	net.lock.Lock()
+	defer net.lock.Unlock()
 
 	//re-initialize the maps
-	self.connMap = make(map[string]int)
-	self.nodeMap = make(map[discover.NodeID]int)
+	net.connMap = make(map[string]int)
+	net.nodeMap = make(map[discover.NodeID]int)
 
-	self.Nodes = nil
-	self.Conns = nil
+	net.Nodes = nil
+	net.Conns = nil
 }
 
 // Node is a wrapper around adapters.Node which is used to track the status
@@ -528,37 +528,37 @@ type Node struct {
 }
 
 // ID returns the ID of the node
-func (self *Node) ID() discover.NodeID {
-	return self.Config.ID
+func (n *Node) ID() discover.NodeID {
+	return n.Config.ID
 }
 
 // String returns a log-friendly string
-func (self *Node) String() string {
-	return fmt.Sprintf("Node %v", self.ID().TerminalString())
+func (n *Node) String() string {
+	return fmt.Sprintf("Node %v", n.ID().TerminalString())
 }
 
 // NodeInfo returns information about the node
-func (self *Node) NodeInfo() *p2p.NodeInfo {
+func (n *Node) NodeInfo() *p2p.NodeInfo {
 	// avoid a panic if the node is not started yet
-	if self.Node == nil {
+	if n.Node == nil {
 		return nil
 	}
-	info := self.Node.NodeInfo()
-	info.Name = self.Config.Name
+	info := n.Node.NodeInfo()
+	info.Name = n.Config.Name
 	return info
 }
 
 // MarshalJSON implements the json.Marshaler interface so that the encoded
 // JSON includes the NodeInfo
-func (self *Node) MarshalJSON() ([]byte, error) {
+func (n *Node) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Info   *p2p.NodeInfo        `json:"info,omitempty"`
 		Config *adapters.NodeConfig `json:"config,omitempty"`
 		Up     bool                 `json:"up"`
 	}{
-		Info:   self.NodeInfo(),
-		Config: self.Config,
-		Up:     self.Up,
+		Info:   n.NodeInfo(),
+		Config: n.Config,
+		Up:     n.Up,
 	})
 }
 
@@ -580,19 +580,19 @@ type Conn struct {
 }
 
 // nodesUp returns whether both nodes are currently up
-func (self *Conn) nodesUp() error {
-	if !self.one.Up {
-		return fmt.Errorf("one %v is not up", self.One)
+func (c *Conn) nodesUp() error {
+	if !c.one.Up {
+		return fmt.Errorf("one %v is not up", c.One)
 	}
-	if !self.other.Up {
-		return fmt.Errorf("other %v is not up", self.Other)
+	if !c.other.Up {
+		return fmt.Errorf("other %v is not up", c.Other)
 	}
 	return nil
 }
 
 // String returns a log-friendly string
-func (self *Conn) String() string {
-	return fmt.Sprintf("Conn %v->%v", self.One.TerminalString(), self.Other.TerminalString())
+func (c *Conn) String() string {
+	return fmt.Sprintf("Conn %v->%v", c.One.TerminalString(), c.Other.TerminalString())
 }
 
 // Msg represents a p2p message sent between two nodes in the network
@@ -605,8 +605,8 @@ type Msg struct {
 }
 
 // String returns a log-friendly string
-func (self *Msg) String() string {
-	return fmt.Sprintf("Msg(%d) %v->%v", self.Code, self.One.TerminalString(), self.Other.TerminalString())
+func (m *Msg) String() string {
+	return fmt.Sprintf("Msg(%d) %v->%v", m.Code, m.One.TerminalString(), m.Other.TerminalString())
 }
 
 // ConnLabel generates a deterministic string which represents a connection
@@ -640,14 +640,14 @@ type NodeSnapshot struct {
 }
 
 // Snapshot creates a network snapshot
-func (self *Network) Snapshot() (*Snapshot, error) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
+func (net *Network) Snapshot() (*Snapshot, error) {
+	net.lock.Lock()
+	defer net.lock.Unlock()
 	snap := &Snapshot{
-		Nodes: make([]NodeSnapshot, len(self.Nodes)),
-		Conns: make([]Conn, len(self.Conns)),
+		Nodes: make([]NodeSnapshot, len(net.Nodes)),
+		Conns: make([]Conn, len(net.Conns)),
 	}
-	for i, node := range self.Nodes {
+	for i, node := range net.Nodes {
 		snap.Nodes[i] = NodeSnapshot{Node: *node}
 		if !node.Up {
 			continue
@@ -658,33 +658,33 @@ func (self *Network) Snapshot() (*Snapshot, error) {
 		}
 		snap.Nodes[i].Snapshots = snapshots
 	}
-	for i, conn := range self.Conns {
+	for i, conn := range net.Conns {
 		snap.Conns[i] = *conn
 	}
 	return snap, nil
 }
 
 // Load loads a network snapshot
-func (self *Network) Load(snap *Snapshot) error {
+func (net *Network) Load(snap *Snapshot) error {
 	for _, n := range snap.Nodes {
-		if _, err := self.NewNodeWithConfig(n.Node.Config); err != nil {
+		if _, err := net.NewNodeWithConfig(n.Node.Config); err != nil {
 			return err
 		}
 		if !n.Node.Up {
 			continue
 		}
-		if err := self.startWithSnapshots(n.Node.Config.ID, n.Snapshots); err != nil {
+		if err := net.startWithSnapshots(n.Node.Config.ID, n.Snapshots); err != nil {
 			return err
 		}
 	}
 	for _, conn := range snap.Conns {
 
-		if !self.GetNode(conn.One).Up || !self.GetNode(conn.Other).Up {
+		if !net.GetNode(conn.One).Up || !net.GetNode(conn.Other).Up {
 			//in this case, at least one of the nodes of a connection is not up,
 			//so it would result in the snapshot `Load` to fail
 			continue
 		}
-		if err := self.Connect(conn.One, conn.Other); err != nil {
+		if err := net.Connect(conn.One, conn.Other); err != nil {
 			return err
 		}
 	}
@@ -692,7 +692,7 @@ func (self *Network) Load(snap *Snapshot) error {
 }
 
 // Subscribe reads control events from a channel and executes them
-func (self *Network) Subscribe(events chan *Event) {
+func (net *Network) Subscribe(events chan *Event) {
 	for {
 		select {
 		case event, ok := <-events:
@@ -700,23 +700,23 @@ func (self *Network) Subscribe(events chan *Event) {
 				return
 			}
 			if event.Control {
-				self.executeControlEvent(event)
+				net.executeControlEvent(event)
 			}
-		case <-self.quitc:
+		case <-net.quitc:
 			return
 		}
 	}
 }
 
-func (self *Network) executeControlEvent(event *Event) {
+func (net *Network) executeControlEvent(event *Event) {
 	log.Trace("execute control event", "type", event.Type, "event", event)
 	switch event.Type {
 	case EventTypeNode:
-		if err := self.executeNodeEvent(event); err != nil {
+		if err := net.executeNodeEvent(event); err != nil {
 			log.Error("error executing node event", "event", event, "err", err)
 		}
 	case EventTypeConn:
-		if err := self.executeConnEvent(event); err != nil {
+		if err := net.executeConnEvent(event); err != nil {
 			log.Error("error executing conn event", "event", event, "err", err)
 		}
 	case EventTypeMsg:
@@ -724,20 +724,21 @@ func (self *Network) executeControlEvent(event *Event) {
 	}
 }
 
-func (self *Network) executeNodeEvent(e *Event) error {
+func (net *Network) executeNodeEvent(e *Event) error {
 	if !e.Node.Up {
-		return self.Stop(e.Node.ID())
+		return net.Stop(e.Node.ID())
 	}
 
-	if _, err := self.NewNodeWithConfig(e.Node.Config); err != nil {
+	if _, err := net.NewNodeWithConfig(e.Node.Config); err != nil {
 		return err
 	}
-	return self.Start(e.Node.ID())
+	return net.Start(e.Node.ID())
 }
 
-func (self *Network) executeConnEvent(e *Event) error {
+func (net *Network) executeConnEvent(e *Event) error {
 	if e.Conn.Up {
-		return self.Connect(e.Conn.One, e.Conn.Other)
+		return net.Connect(e.Conn.One, e.Conn.Other)
+	} else {
+		return net.Disconnect(e.Conn.One, e.Conn.Other)
 	}
-	return self.Disconnect(e.Conn.One, e.Conn.Other)
 }
diff --git a/p2p/testing/peerpool.go b/p2p/testing/peerpool.go
index 45c6e61425..ed00396e23 100644
--- a/p2p/testing/peerpool.go
+++ b/p2p/testing/peerpool.go
@@ -39,29 +39,29 @@ func NewTestPeerPool() *TestPeerPool {
 	return &TestPeerPool{peers: make(map[discover.NodeID]TestPeer)}
 }
 
-func (self *TestPeerPool) Add(p TestPeer) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	log.Trace(fmt.Sprintf("pp add peer  %v", p.ID()))
-	self.peers[p.ID()] = p
+func (p *TestPeerPool) Add(peer TestPeer) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	log.Trace(fmt.Sprintf("pp add peer  %v", peer.ID()))
+	p.peers[peer.ID()] = peer
 
 }
 
-func (self *TestPeerPool) Remove(p TestPeer) {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	delete(self.peers, p.ID())
+func (p *TestPeerPool) Remove(peer TestPeer) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	delete(p.peers, peer.ID())
 }
 
-func (self *TestPeerPool) Has(id discover.NodeID) bool {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	_, ok := self.peers[id]
+func (p *TestPeerPool) Has(id discover.NodeID) bool {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	_, ok := p.peers[id]
 	return ok
 }
 
-func (self *TestPeerPool) Get(id discover.NodeID) TestPeer {
-	self.lock.Lock()
-	defer self.lock.Unlock()
-	return self.peers[id]
+func (p *TestPeerPool) Get(id discover.NodeID) TestPeer {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	return p.peers[id]
 }
diff --git a/p2p/testing/protocolsession.go b/p2p/testing/protocolsession.go
index 361285f06e..8f73bfa03e 100644
--- a/p2p/testing/protocolsession.go
+++ b/p2p/testing/protocolsession.go
@@ -78,10 +78,10 @@ type Disconnect struct {
 }
 
 // trigger sends messages from peers
-func (self *ProtocolSession) trigger(trig Trigger) error {
-	simNode, ok := self.adapter.GetNode(trig.Peer)
+func (s *ProtocolSession) trigger(trig Trigger) error {
+	simNode, ok := s.adapter.GetNode(trig.Peer)
 	if !ok {
-		return fmt.Errorf("trigger: peer %v does not exist (1- %v)", trig.Peer, len(self.IDs))
+		return fmt.Errorf("trigger: peer %v does not exist (1- %v)", trig.Peer, len(s.IDs))
 	}
 	mockNode, ok := simNode.Services()[0].(*mockNode)
 	if !ok {
@@ -107,7 +107,7 @@ func (self *ProtocolSession) trigger(trig Trigger) error {
 }
 
 // expect checks an expectation of a message sent out by the pivot node
-func (self *ProtocolSession) expect(exps []Expect) error {
+func (s *ProtocolSession) expect(exps []Expect) error {
 	// construct a map of expectations for each node
 	peerExpects := make(map[discover.NodeID][]Expect)
 	for _, exp := range exps {
@@ -120,9 +120,9 @@ func (self *ProtocolSession) expect(exps []Expect) error {
 	// construct a map of mockNodes for each node
 	mockNodes := make(map[discover.NodeID]*mockNode)
 	for nodeID := range peerExpects {
-		simNode, ok := self.adapter.GetNode(nodeID)
+		simNode, ok := s.adapter.GetNode(nodeID)
 		if !ok {
-			return fmt.Errorf("trigger: peer %v does not exist (1- %v)", nodeID, len(self.IDs))
+			return fmt.Errorf("trigger: peer %v does not exist (1- %v)", nodeID, len(s.IDs))
 		}
 		mockNode, ok := simNode.Services()[0].(*mockNode)
 		if !ok {
@@ -202,9 +202,9 @@ func (self *ProtocolSession) expect(exps []Expect) error {
 }
 
 // TestExchanges tests a series of exchanges against the session
-func (self *ProtocolSession) TestExchanges(exchanges ...Exchange) error {
+func (s *ProtocolSession) TestExchanges(exchanges ...Exchange) error {
 	for i, e := range exchanges {
-		if err := self.testExchange(e); err != nil {
+		if err := s.testExchange(e); err != nil {
 			return fmt.Errorf("exchange #%d %q: %v", i, e.Label, err)
 		}
 		log.Trace(fmt.Sprintf("exchange #%d %q: run successfully", i, e.Label))
@@ -214,14 +214,14 @@ func (self *ProtocolSession) TestExchanges(exchanges ...Exchange) error {
 
 // testExchange tests a single Exchange.
 // Default timeout value is 2 seconds.
-func (self *ProtocolSession) testExchange(e Exchange) error {
+func (s *ProtocolSession) testExchange(e Exchange) error {
 	errc := make(chan error)
 	done := make(chan struct{})
 	defer close(done)
 
 	go func() {
 		for _, trig := range e.Triggers {
-			err := self.trigger(trig)
+			err := s.trigger(trig)
 			if err != nil {
 				errc <- err
 				return
@@ -229,7 +229,7 @@ func (self *ProtocolSession) testExchange(e Exchange) error {
 		}
 
 		select {
-		case errc <- self.expect(e.Expects):
+		case errc <- s.expect(e.Expects):
 		case <-done:
 		}
 	}()
@@ -250,7 +250,7 @@ func (self *ProtocolSession) testExchange(e Exchange) error {
 
 // TestDisconnected tests the disconnections given as arguments
 // the disconnect structs describe what disconnect error is expected on which peer
-func (self *ProtocolSession) TestDisconnected(disconnects ...*Disconnect) error {
+func (s *ProtocolSession) TestDisconnected(disconnects ...*Disconnect) error {
 	expects := make(map[discover.NodeID]error)
 	for _, disconnect := range disconnects {
 		expects[disconnect.Peer] = disconnect.Error
@@ -259,7 +259,7 @@ func (self *ProtocolSession) TestDisconnected(disconnects ...*Disconnect) error
 	timeout := time.After(time.Second)
 	for len(expects) > 0 {
 		select {
-		case event := <-self.events:
+		case event := <-s.events:
 			if event.Type != p2p.PeerEventTypeDrop {
 				continue
 			}
diff --git a/p2p/testing/protocoltester.go b/p2p/testing/protocoltester.go
index a797412d60..636613c57a 100644
--- a/p2p/testing/protocoltester.go
+++ b/p2p/testing/protocoltester.go
@@ -101,24 +101,24 @@ func NewProtocolTester(t *testing.T, id discover.NodeID, n int, run func(*p2p.Pe
 }
 
 // Stop stops the p2p server
-func (self *ProtocolTester) Stop() error {
-	self.Server.Stop()
+func (t *ProtocolTester) Stop() error {
+	t.Server.Stop()
 	return nil
 }
 
 // Connect brings up the remote peer node and connects it using the
 // p2p/simulations network connection with the in memory network adapter
-func (self *ProtocolTester) Connect(selfID discover.NodeID, peers ...*adapters.NodeConfig) {
+func (t *ProtocolTester) Connect(selfID discover.NodeID, peers ...*adapters.NodeConfig) {
 	for _, peer := range peers {
 		log.Trace(fmt.Sprintf("start node %v", peer.ID))
-		if _, err := self.network.NewNodeWithConfig(peer); err != nil {
+		if _, err := t.network.NewNodeWithConfig(peer); err != nil {
 			panic(fmt.Sprintf("error starting peer %v: %v", peer.ID, err))
 		}
-		if err := self.network.Start(peer.ID); err != nil {
+		if err := t.network.Start(peer.ID); err != nil {
 			panic(fmt.Sprintf("error starting peer %v: %v", peer.ID, err))
 		}
 		log.Trace(fmt.Sprintf("connect to %v", peer.ID))
-		if err := self.network.Connect(selfID, peer.ID); err != nil {
+		if err := t.network.Connect(selfID, peer.ID); err != nil {
 			panic(fmt.Sprintf("error connecting to peer %v: %v", peer.ID, err))
 		}
 	}
diff --git a/params/version.go b/params/version.go
index 8b96f25167..1e8c43bf81 100644
--- a/params/version.go
+++ b/params/version.go
@@ -23,7 +23,7 @@ import (
 const (
 	VersionMajor = 1          // Major version component of the current release
 	VersionMinor = 8          // Minor version component of the current release
-	VersionPatch = 8          // Patch version component of the current release
+	VersionPatch = 9          // Patch version component of the current release
 	VersionMeta  = "unstable" // Version metadata to append to the version string
 )
 
diff --git a/rlp/decode.go b/rlp/decode.go
index 60d9dab2b5..dbbe599597 100644
--- a/rlp/decode.go
+++ b/rlp/decode.go
@@ -29,6 +29,23 @@ import (
 )
 
 var (
+	// EOL is returned when the end of the current list
+	// has been reached during streaming.
+	EOL = errors.New("rlp: end of list")
+
+	// Actual Errors
+	ErrExpectedString   = errors.New("rlp: expected String or Byte")
+	ErrExpectedList     = errors.New("rlp: expected List")
+	ErrCanonInt         = errors.New("rlp: non-canonical integer format")
+	ErrCanonSize        = errors.New("rlp: non-canonical size information")
+	ErrElemTooLarge     = errors.New("rlp: element is larger than containing list")
+	ErrValueTooLarge    = errors.New("rlp: value size exceeds available input length")
+	ErrMoreThanOneValue = errors.New("rlp: input contains more than one value")
+
+	// internal errors
+	errNotInList     = errors.New("rlp: call of ListEnd outside of any list")
+	errNotAtEOL      = errors.New("rlp: call of ListEnd not positioned at EOL")
+	errUintOverflow  = errors.New("rlp: uint overflow")
 	errNoPointer     = errors.New("rlp: interface given to Decode must be a pointer")
 	errDecodeIntoNil = errors.New("rlp: pointer given to Decode must not be nil")
 )
@@ -274,9 +291,8 @@ func makeListDecoder(typ reflect.Type, tag tags) (decoder, error) {
 	if etype.Kind() == reflect.Uint8 && !reflect.PtrTo(etype).Implements(decoderInterface) {
 		if typ.Kind() == reflect.Array {
 			return decodeByteArray, nil
-		} else {
-			return decodeByteSlice, nil
 		}
+		return decodeByteSlice, nil
 	}
 	etypeinfo, err := cachedTypeInfo1(etype, tags{})
 	if err != nil {
@@ -555,29 +571,6 @@ func (k Kind) String() string {
 	}
 }
 
-var (
-	// EOL is returned when the end of the current list
-	// has been reached during streaming.
-	EOL = errors.New("rlp: end of list")
-
-	// Actual Errors
-	ErrExpectedString = errors.New("rlp: expected String or Byte")
-	ErrExpectedList   = errors.New("rlp: expected List")
-	ErrCanonInt       = errors.New("rlp: non-canonical integer format")
-	ErrCanonSize      = errors.New("rlp: non-canonical size information")
-	ErrElemTooLarge   = errors.New("rlp: element is larger than containing list")
-	ErrValueTooLarge  = errors.New("rlp: value size exceeds available input length")
-
-	// This error is reported by DecodeBytes if the slice contains
-	// additional data after the first RLP value.
-	ErrMoreThanOneValue = errors.New("rlp: input contains more than one value")
-
-	// internal errors
-	errNotInList    = errors.New("rlp: call of ListEnd outside of any list")
-	errNotAtEOL     = errors.New("rlp: call of ListEnd not positioned at EOL")
-	errUintOverflow = errors.New("rlp: uint overflow")
-)
-
 // ByteReader must be implemented by any input reader for a Stream. It
 // is implemented by e.g. bufio.Reader and bytes.Reader.
 type ByteReader interface {
diff --git a/rlp/encode.go b/rlp/encode.go
index 44592c2f53..445b4b5b21 100644
--- a/rlp/encode.go
+++ b/rlp/encode.go
@@ -92,7 +92,7 @@ func Encode(w io.Writer, val interface{}) error {
 	return eb.toWriter(w)
 }
 
-// EncodeBytes returns the RLP encoding of val.
+// EncodeToBytes returns the RLP encoding of val.
 // Please see the documentation of Encode for the encoding rules.
 func EncodeToBytes(val interface{}) ([]byte, error) {
 	eb := encbufPool.Get().(*encbuf)
@@ -104,7 +104,7 @@ func EncodeToBytes(val interface{}) ([]byte, error) {
 	return eb.toBytes(), nil
 }
 
-// EncodeReader returns a reader from which the RLP encoding of val
+// EncodeToReader returns a reader from which the RLP encoding of val
 // can be read. The returned size is the total size of the encoded
 // data.
 //
@@ -151,11 +151,10 @@ func puthead(buf []byte, smalltag, largetag byte, size uint64) int {
 	if size < 56 {
 		buf[0] = smalltag + byte(size)
 		return 1
-	} else {
-		sizesize := putint(buf[1:], size)
-		buf[0] = largetag + byte(sizesize)
-		return sizesize + 1
 	}
+	sizesize := putint(buf[1:], size)
+	buf[0] = largetag + byte(sizesize)
+	return sizesize + 1
 }
 
 // encbufs are pooled.
@@ -218,7 +217,7 @@ func (w *encbuf) list() *listhead {
 func (w *encbuf) listEnd(lh *listhead) {
 	lh.size = w.size() - lh.offset - lh.size
 	if lh.size < 56 {
-		w.lhsize += 1 // length encoded into kind tag
+		w.lhsize++ // length encoded into kind tag
 	} else {
 		w.lhsize += 1 + intsize(uint64(lh.size))
 	}
@@ -322,10 +321,9 @@ func (r *encReader) next() []byte {
 			p := r.buf.str[r.strpos:head.offset]
 			r.strpos += sizebefore
 			return p
-		} else {
-			r.lhpos++
-			return head.encode(r.buf.sizebuf)
 		}
+		r.lhpos++
+		return head.encode(r.buf.sizebuf)
 
 	case r.strpos < len(r.buf.str):
 		// String data at the end, after all list headers.
@@ -576,9 +574,8 @@ func makePtrWriter(typ reflect.Type) (writer, error) {
 	writer := func(val reflect.Value, w *encbuf) error {
 		if val.IsNil() {
 			return nilfunc(w)
-		} else {
-			return etypeinfo.writer(val.Elem(), w)
 		}
+		return etypeinfo.writer(val.Elem(), w)
 	}
 	return writer, err
 }
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.