comparing it with '==' (as in err == xxxErr) is no longer the best practice with Go 1.13 (Q3 2019)

accounts/abi/bind/util_test.go

@@ -87,7 +87,7 @@ func TestWaitDeployed(t *testing.T) {
 
 		select {
 		case <-mined:
-			if err != test.wantErr {
+			if !errors.Is(err, test.wantErr) {
 				t.Errorf("test %q: error mismatch: want %q, got %q", name, test.wantErr, err)
 			}
 			if address != test.wantAddress {

accounts/abi/unpack_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"encoding/hex"
 	"fmt"
+	"github.com/pkg/errors"
 	"math"
 	"math/big"
 	"reflect"
@@ -1106,7 +1107,7 @@ func TestPackAndUnpackIncompatibleNumber(t *testing.T) {
 			{Type: ty},
 		}
 		decoded, err := decodeABI.Unpack(packed)
-		if err != testCase.err {
+		if !errors.Is(err, testCase.err) {
 			t.Fatalf("Expected error %v, actual error %v. case %d", testCase.err, err, i)
 		}
 		if err != nil {

accounts/keystore/keystore_test.go

@@ -17,6 +17,8 @@
 package keystore
 
 import (
+	"errors"
+	"github.com/pkg/errors"
 	"math/rand"
 	"os"
 	"runtime"
@@ -127,7 +129,7 @@ func TestTimedUnlock(t *testing.T) {
 
 	// Signing without passphrase fails because account is locked
 	_, err = ks.SignHash(accounts.Account{Address: a1.Address}, testSigData)
-	if err != ErrLocked {
+	if !errors.Is(err, ErrLocked) {
 		t.Fatal("Signing should've failed with ErrLocked before unlocking, got ", err)
 	}
 
@@ -145,7 +147,7 @@ func TestTimedUnlock(t *testing.T) {
 	// Signing fails again after automatic locking
 	time.Sleep(250 * time.Millisecond)
 	_, err = ks.SignHash(accounts.Account{Address: a1.Address}, testSigData)
-	if err != ErrLocked {
+	if !errors.Is(err, ErrLocked) {
 		t.Fatal("Signing should've failed with ErrLocked timeout expired, got ", err)
 	}
 }
@@ -185,7 +187,7 @@ func TestOverrideUnlock(t *testing.T) {
 	// Signing fails again after automatic locking
 	time.Sleep(250 * time.Millisecond)
 	_, err = ks.SignHash(accounts.Account{Address: a1.Address}, testSigData)
-	if err != ErrLocked {
+	if !errors.Is(err, ErrLocked) {
 		t.Fatal("Signing should've failed with ErrLocked timeout expired, got ", err)
 	}
 }
@@ -206,7 +208,7 @@ func TestSignRace(t *testing.T) {
 	}
 	end := time.Now().Add(500 * time.Millisecond)
 	for time.Now().Before(end) {
-		if _, err := ks.SignHash(accounts.Account{Address: a1.Address}, testSigData); err == ErrLocked {
+		if _, err := ks.SignHash(accounts.Account{Address: a1.Address}, testSigData); errors.Is(err, ErrLocked) {
 			return
 		} else if err != nil {
 			t.Errorf("Sign error: %v", err)

accounts/keystore/plain_test.go

@@ -20,6 +20,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"fmt"
+	"github.com/pkg/errors"
 	"path/filepath"
 	"reflect"
 	"strings"
@@ -90,7 +91,7 @@ func TestKeyStorePassphraseDecryptionFail(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if _, err = ks.GetKey(k1.Address, account.URL.Path, "bar"); err != ErrDecrypt {
+	if _, err = ks.GetKey(k1.Address, account.URL.Path, "bar"); !errors.Is(err, ErrDecrypt) {
 		t.Fatalf("wrong error for invalid password\ngot %q\nwant %q", err, ErrDecrypt)
 	}
 }

accounts/usbwallet/ledger.go

@@ -119,7 +119,7 @@ func (w *ledgerDriver) Open(device io.ReadWriter, passphrase string) error {
 	_, err := w.ledgerDerive(accounts.DefaultBaseDerivationPath)
 	if err != nil {
 		// Ethereum app is not running or in browser mode, nothing more to do, return
-		if err == errLedgerReplyInvalidHeader {
+		if errors.Is(err, errLedgerReplyInvalidHeader) {
 			w.browser = true
 		}
 		return nil
@@ -141,7 +141,7 @@ func (w *ledgerDriver) Close() error {
 // Heartbeat implements usbwallet.driver, performing a sanity check against the
 // Ledger to see if it's still online.
 func (w *ledgerDriver) Heartbeat() error {
-	if _, err := w.ledgerVersion(); err != nil && err != errLedgerInvalidVersionReply {
+	if _, err := w.ledgerVersion(); err != nil && !errors.Is(err, errLedgerInvalidVersionReply) {
 		w.failure = err
 		return err
 	}

beacon/light/committee_chain_test.go

@@ -18,6 +18,8 @@ package light
 
 import (
 	"crypto/rand"
+	"errors"
+	"github.com/pkg/errors"
 	"testing"
 	"time"
 
@@ -259,13 +261,13 @@ func (c *committeeChainTest) setClockPeriod(period float64) {
 }
 
 func (c *committeeChainTest) addFixedCommitteeRoot(tc *testCommitteeChain, period uint64, expErr error) {
-	if err := c.chain.addFixedCommitteeRoot(period, tc.periods[period].committee.Root()); err != expErr {
+	if err := c.chain.addFixedCommitteeRoot(period, tc.periods[period].committee.Root()); !errors.Is(err, expErr) {
 		c.t.Errorf("Incorrect error output from addFixedCommitteeRoot at period %d (expected %v, got %v)", period, expErr, err)
 	}
 }
 
 func (c *committeeChainTest) addCommittee(tc *testCommitteeChain, period uint64, expErr error) {
-	if err := c.chain.addCommittee(period, tc.periods[period].committee); err != expErr {
+	if err := c.chain.addCommittee(period, tc.periods[period].committee); !errors.Is(err, expErr) {
 		c.t.Errorf("Incorrect error output from addCommittee at period %d (expected %v, got %v)", period, expErr, err)
 	}
 }
@@ -275,7 +277,7 @@ func (c *committeeChainTest) insertUpdate(tc *testCommitteeChain, period uint64,
 	if addCommittee {
 		committee = tc.periods[period+1].committee
 	}
-	if err := c.chain.InsertUpdate(tc.periods[period].update, committee); err != expErr {
+	if err := c.chain.InsertUpdate(tc.periods[period].update, committee); !errors.Is(err, expErr) {
 		c.t.Errorf("Incorrect error output from InsertUpdate at period %d (expected %v, got %v)", period, expErr, err)
 	}
 }

cmd/clef/main.go

@@ -923,13 +923,13 @@ func testExternalUI(api *core.SignerAPI) {
 		}
 	}
 	expectApprove := func(testcase string, err error) {
-		if err == nil || err == accounts.ErrUnknownAccount {
+		if err == nil || errors.Is(err, accounts.ErrUnknownAccount) {
 			return
 		}
 		addErr(fmt.Sprintf("%v: expected no error, got %v", testcase, err.Error()))
 	}
 	expectDeny := func(testcase string, err error) {
-		if err == nil || err != core.ErrRequestDenied {
+		if err == nil || !errors.Is(err, core.ErrRequestDenied) {
 			addErr(fmt.Sprintf("%v: expected ErrRequestDenied, got %v", testcase, err))
 		}
 	}

cmd/devp2p/internal/v5test/discv5tests.go

@@ -18,6 +18,7 @@ package v5test
 
 import (
 	"bytes"
+	"github.com/pkg/errors"
 	"net"
 	"sync"
 	"time"
@@ -95,7 +96,7 @@ func (s *Suite) TestPingLargeRequestID(t *utesting.T) {
 	case *v5wire.Pong:
 		t.Errorf("PONG response with unknown request ID %x", resp.ReqID)
 	case *readError:
-		if resp.err == v5wire.ErrInvalidReqID {
+		if errors.Is(resp.err, v5wire.ErrInvalidReqID) {
 			t.Error("response with oversized request ID")
 		} else if !netutil.IsTimeout(resp.err) {
 			t.Error(resp)

cmd/geth/accountcmd.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	"fmt"
+	"github.com/pkg/errors"
 	"os"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -237,7 +238,7 @@ func unlockAccount(ks *keystore.KeyStore, address string, i int, passwords []str
 			log.Info("Unlocked account", "address", account.Address.Hex())
 			return ambiguousAddrRecovery(ks, err, password), password
 		}
-		if err != keystore.ErrDecrypt {
+		if !errors.Is(err, keystore.ErrDecrypt) {
 			// No need to prompt again if the error is not decryption-related.
 			break
 		}

cmd/rlpdump/main.go

@@ -24,6 +24,7 @@ import (
 	"encoding/hex"
 	"flag"
 	"fmt"
+	"github.com/pkg/errors"
 	"io"
 	"math"
 	"os"
@@ -149,7 +150,7 @@ func dump(in *inStream, s *rlp.Stream, depth int, out io.Writer) error {
 				if i > 0 {
 					fmt.Fprint(out, ",\n")
 				}
-				if err := dump(in, s, depth+1, out); err == rlp.EOL {
+				if err := dump(in, s, depth+1, out); errors.Is(err, rlp.EOL) {
 					break
 				} else if err != nil {
 					return err

common/bitutil/compress_test.go

@@ -18,7 +18,9 @@ package bitutil
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/rand"
 	"testing"
 
@@ -107,7 +109,7 @@ func TestDecodingCycle(t *testing.T) {
 		data := hexutil.MustDecode(tt.input)
 
 		orig, err := bitsetDecodeBytes(data, tt.size)
-		if err != tt.fail {
+		if !errors.Is(err, tt.fail) {
 			t.Errorf("test %d: failure mismatch: have %v, want %v", i, err, tt.fail)
 		}
 		if err != nil {
@@ -143,7 +145,7 @@ func TestCompression(t *testing.T) {
 		t.Errorf("decoding mismatch for dense data: have %x, want %x, error %v", data, in, err)
 	}
 	// Check that decompressing a longer input than the target fails
-	if _, err := DecompressBytes([]byte{0xc0, 0x01, 0x01}, 2); err != errExceededTarget {
+	if _, err := DecompressBytes([]byte{0xc0, 0x01, 0x01}, 2); !errors.Is(err, errExceededTarget) {
 		t.Errorf("decoding error mismatch for long data: have %v, want %v", err, errExceededTarget)
 	}
 }

common/hexutil/hexutil.go

@@ -33,6 +33,7 @@ package hexutil
 import (
 	"encoding/hex"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/big"
 	"strconv"
 )
@@ -234,7 +235,7 @@ func mapError(err error) error {
 	if _, ok := err.(hex.InvalidByteError); ok {
 		return ErrSyntax
 	}
-	if err == hex.ErrLength {
+	if errors.Is(err, hex.ErrLength) {
 		return ErrOddLength
 	}
 	return err

common/hexutil/json.go

@@ -20,6 +20,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/big"
 	"reflect"
 	"strconv"
@@ -355,7 +356,7 @@ func (b *Uint) UnmarshalJSON(input []byte) error {
 func (b *Uint) UnmarshalText(input []byte) error {
 	var u64 Uint64
 	err := u64.UnmarshalText(input)
-	if u64 > Uint64(^uint(0)) || err == ErrUint64Range {
+	if u64 > Uint64(^uint(0)) || errors.Is(err, ErrUint64Range) {
 		return ErrUintRange
 	} else if err != nil {
 		return err

consensus/clique/snapshot_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"crypto/ecdsa"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/big"
 	"testing"
 
@@ -470,7 +471,7 @@ func (tt *cliqueTest) run(t *testing.T) {
 			break
 		}
 	}
-	if _, err = chain.InsertChain(batches[len(batches)-1]); err != tt.failure {
+	if _, err = chain.InsertChain(batches[len(batches)-1]); !errors.Is(err, tt.failure) {
 		t.Errorf("failure mismatch: have %v, want %v", err, tt.failure)
 	}
 	if tt.failure != nil {

console/console.go

@@ -448,7 +448,7 @@ func (c *Console) Interactive() {
 			return
 
 		case err := <-inputErr:
-			if err == liner.ErrPromptAborted {
+			if errors.Is(err, liner.ErrPromptAborted) {
 				// When prompting for multi-line input, the first Ctrl-C resets
 				// the multi-line state.
 				prompt, indents, input = c.prompt, 0, ""

core/blockchain.go

@@ -1251,7 +1251,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 	// Write downloaded chain data and corresponding receipt chain data
 	if len(ancientBlocks) > 0 {
 		if n, err := writeAncient(ancientBlocks, ancientReceipts); err != nil {
-			if err == errInsertionInterrupted {
+			if errors.Is(err, errInsertionInterrupted) {
 				return 0, nil
 			}
 			return n, err
@@ -1259,7 +1259,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 	}
 	if len(liveBlocks) > 0 {
 		if n, err := writeLive(liveBlocks, liveReceipts); err != nil {
-			if err == errInsertionInterrupted {
+			if errors.Is(err, errInsertionInterrupted) {
 				return 0, nil
 			}
 			return n, err

core/blockchain_test.go

@@ -154,7 +154,7 @@ func testBlockChainImport(chain types.Blocks, blockchain *BlockChain) error {
 			err = blockchain.validator.ValidateBody(block)
 		}
 		if err != nil {
-			if err == ErrKnownBlock {
+			if errors.Is(err, ErrKnownBlock) {
 				continue
 			}
 			return err

core/forkid/forkid_test.go

@@ -18,6 +18,7 @@ package forkid
 
 import (
 	"bytes"
+	"github.com/pkg/errors"
 	"hash/crc32"
 	"math"
 	"math/big"
@@ -359,7 +360,7 @@ func TestValidation(t *testing.T) {
 	genesis := core.DefaultGenesisBlock().ToBlock()
 	for i, tt := range tests {
 		filter := newFilter(tt.config, genesis, func() (uint64, uint64) { return tt.head, tt.time })
-		if err := filter(tt.id); err != tt.err {
+		if err := filter(tt.id); !errors.Is(err, tt.err) {
 			t.Errorf("test %d: validation error mismatch: have %v, want %v", i, err, tt.err)
 		}
 	}

core/rawdb/freezer_table_test.go

@@ -19,7 +19,9 @@ package rawdb
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/rand"
 	"os"
 	"path/filepath"
@@ -68,7 +70,7 @@ func TestFreezerBasics(t *testing.T) {
 	}
 	// Check that we cannot read too far
 	_, err = f.Retrieve(uint64(255))
-	if err != errOutOfBounds {
+	if !errors.Is(err, errOutOfBounds) {
 		t.Fatal(err)
 	}
 }
@@ -878,7 +880,7 @@ func checkRetrieveError(t *testing.T, f *freezerTable, items map[uint64]error) {
 		if err == nil {
 			t.Fatalf("unexpected value %x for item %d, want error %v", item, value, wantError)
 		}
-		if err != wantError {
+		if !errors.Is(err, wantError) {
 			t.Fatalf("wrong error for item %d: %v", item, err)
 		}
 	}

core/rawdb/freezer_test.go

@@ -105,7 +105,7 @@ func TestFreezerModifyRollback(t *testing.T) {
 		require.NoError(t, op.AppendRaw("test", 2, make([]byte, 2048)))
 		return theError
 	})
-	if err != theError {
+	if !errors.Is(err, theError) {
 		t.Errorf("ModifyAncients returned wrong error %q", err)
 	}
 	checkAncientCount(t, f, "test", 0)
@@ -373,7 +373,7 @@ func checkAncientCount(t *testing.T, f *Freezer, kind string, n uint64) {
 	}
 	if _, err := f.Ancient(kind, index); err == nil {
 		t.Errorf("Ancient(%q, %d) didn't return expected error", kind, index)
-	} else if err != errOutOfBounds {
+	} else if !errors.Is(err, errOutOfBounds) {
 		t.Errorf("Ancient(%q, %d) returned unexpected error %q", kind, index, err)
 	}
 }

core/state/snapshot/disklayer_test.go

@@ -18,6 +18,8 @@ package snapshot
 
 import (
 	"bytes"
+	"errors"
+	"github.com/pkg/errors"
 	"testing"
 
 	"github.com/VictoriaMetrics/fastcache"
@@ -311,7 +313,7 @@ func TestDiskPartialMerge(t *testing.T) {
 		assertAccount := func(account common.Hash, data []byte) {
 			t.Helper()
 			blob, err := base.AccountRLP(account)
-			if bytes.Compare(account[:], genMarker) > 0 && err != ErrNotCoveredYet {
+			if bytes.Compare(account[:], genMarker) > 0 && !errors.Is(err, ErrNotCoveredYet) {
 				t.Fatalf("test %d: post-marker (%x) account access (%x) succeeded: %x", i, genMarker, account, blob)
 			}
 			if bytes.Compare(account[:], genMarker) <= 0 && !bytes.Equal(blob, data) {
@@ -327,7 +329,7 @@ func TestDiskPartialMerge(t *testing.T) {
 		assertStorage := func(account common.Hash, slot common.Hash, data []byte) {
 			t.Helper()
 			blob, err := base.Storage(account, slot)
-			if bytes.Compare(append(account[:], slot[:]...), genMarker) > 0 && err != ErrNotCoveredYet {
+			if bytes.Compare(append(account[:], slot[:]...), genMarker) > 0 && !errors.Is(err, ErrNotCoveredYet) {
 				t.Fatalf("test %d: post-marker (%x) storage access (%x:%x) succeeded: %x", i, genMarker, account, slot, blob)
 			}
 			if bytes.Compare(append(account[:], slot[:]...), genMarker) <= 0 && !bytes.Equal(blob, data) {

core/state/snapshot/snapshot_test.go

@@ -19,7 +19,9 @@ package snapshot
 import (
 	crand "crypto/rand"
 	"encoding/binary"
+	"errors"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/rand"
 	"testing"
 	"time"
@@ -118,10 +120,10 @@ func TestDiskLayerExternalInvalidationFullFlatten(t *testing.T) {
 		t.Fatalf("failed to merge diff layer onto disk: %v", err)
 	}
 	// Since the base layer was modified, ensure that data retrievals on the external reference fail
-	if acc, err := ref.Account(common.HexToHash("0x01")); err != ErrSnapshotStale {
+	if acc, err := ref.Account(common.HexToHash("0x01")); !errors.Is(err, ErrSnapshotStale) {
 		t.Errorf("stale reference returned account: %#x (err: %v)", acc, err)
 	}
-	if slot, err := ref.Storage(common.HexToHash("0xa1"), common.HexToHash("0xb1")); err != ErrSnapshotStale {
+	if slot, err := ref.Storage(common.HexToHash("0xa1"), common.HexToHash("0xb1")); !errors.Is(err, ErrSnapshotStale) {
 		t.Errorf("stale reference returned storage slot: %#x (err: %v)", slot, err)
 	}
 	if n := len(snaps.layers); n != 1 {
@@ -168,10 +170,10 @@ func TestDiskLayerExternalInvalidationPartialFlatten(t *testing.T) {
 		t.Fatalf("failed to merge accumulator onto disk: %v", err)
 	}
 	// Since the base layer was modified, ensure that data retrievals on the external reference fail
-	if acc, err := ref.Account(common.HexToHash("0x01")); err != ErrSnapshotStale {
+	if acc, err := ref.Account(common.HexToHash("0x01")); !errors.Is(err, ErrSnapshotStale) {
 		t.Errorf("stale reference returned account: %#x (err: %v)", acc, err)
 	}
-	if slot, err := ref.Storage(common.HexToHash("0xa1"), common.HexToHash("0xb1")); err != ErrSnapshotStale {
+	if slot, err := ref.Storage(common.HexToHash("0xa1"), common.HexToHash("0xb1")); !errors.Is(err, ErrSnapshotStale) {
 		t.Errorf("stale reference returned storage slot: %#x (err: %v)", slot, err)
 	}
 	if n := len(snaps.layers); n != 2 {
@@ -230,10 +232,10 @@ func TestDiffLayerExternalInvalidationPartialFlatten(t *testing.T) {
 		t.Fatalf("failed to flatten diff layer into accumulator: %v", err)
 	}
 	// Since the accumulator diff layer was modified, ensure that data retrievals on the external reference fail
-	if acc, err := ref.Account(common.HexToHash("0x01")); err != ErrSnapshotStale {
+	if acc, err := ref.Account(common.HexToHash("0x01")); !errors.Is(err, ErrSnapshotStale) {
 		t.Errorf("stale reference returned account: %#x (err: %v)", acc, err)
 	}
-	if slot, err := ref.Storage(common.HexToHash("0xa1"), common.HexToHash("0xb1")); err != ErrSnapshotStale {
+	if slot, err := ref.Storage(common.HexToHash("0xa1"), common.HexToHash("0xb1")); !errors.Is(err, ErrSnapshotStale) {
 		t.Errorf("stale reference returned storage slot: %#x (err: %v)", slot, err)
 	}
 	if n := len(snaps.layers); n != 3 {

core/state_transition.go

@@ -18,6 +18,7 @@ package core
 
 import (
 	"fmt"
+	"github.com/pkg/errors"
 	"math"
 	"math/big"
 
@@ -60,7 +61,7 @@ func (result *ExecutionResult) Return() []byte {
 // Revert returns the concrete revert reason if the execution is aborted by `REVERT`
 // opcode. Note the reason can be nil if no data supplied with revert opcode.
 func (result *ExecutionResult) Revert() []byte {
-	if result.Err != vm.ErrExecutionReverted {
+	if !errors.Is(result.Err, vm.ErrExecutionReverted) {
 		return nil
 	}
 	return common.CopyBytes(result.ReturnData)

core/txpool/legacypool/legacypool_test.go

@@ -421,7 +421,7 @@ func TestNegativeValue(t *testing.T) {
 	tx, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(-1), 100, big.NewInt(1), nil), types.HomesteadSigner{}, key)
 	from, _ := deriveSender(tx)
 	testAddBalance(pool, from, big.NewInt(1))
-	if err := pool.addRemote(tx); err != txpool.ErrNegativeValue {
+	if err := pool.addRemote(tx); !errors.Is(err, txpool.ErrNegativeValue) {
 		t.Error("expected", txpool.ErrNegativeValue, "got", err)
 	}
 }
@@ -434,7 +434,7 @@ func TestTipAboveFeeCap(t *testing.T) {
 
 	tx := dynamicFeeTx(0, 100, big.NewInt(1), big.NewInt(2), key)
 
-	if err := pool.addRemote(tx); err != core.ErrTipAboveFeeCap {
+	if err := pool.addRemote(tx); !errors.Is(err, core.ErrTipAboveFeeCap) {
 		t.Error("expected", core.ErrTipAboveFeeCap, "got", err)
 	}
 }
@@ -449,12 +449,12 @@ func TestVeryHighValues(t *testing.T) {
 	veryBigNumber.Lsh(veryBigNumber, 300)
 
 	tx := dynamicFeeTx(0, 100, big.NewInt(1), veryBigNumber, key)
-	if err := pool.addRemote(tx); err != core.ErrTipVeryHigh {
+	if err := pool.addRemote(tx); !errors.Is(err, core.ErrTipVeryHigh) {
 		t.Error("expected", core.ErrTipVeryHigh, "got", err)
 	}
 
 	tx2 := dynamicFeeTx(0, 100, veryBigNumber, big.NewInt(1), key)
-	if err := pool.addRemote(tx2); err != core.ErrFeeCapVeryHigh {
+	if err := pool.addRemote(tx2); !errors.Is(err, core.ErrFeeCapVeryHigh) {
 		t.Error("expected", core.ErrFeeCapVeryHigh, "got", err)
 	}
 }
@@ -1809,7 +1809,7 @@ func TestUnderpricing(t *testing.T) {
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
 	// Ensure that replacing a pending transaction with a future transaction fails
-	if err := pool.addRemote(pricedTransaction(5, 100000, big.NewInt(6), keys[1])); err != txpool.ErrFutureReplacePending {
+	if err := pool.addRemote(pricedTransaction(5, 100000, big.NewInt(6), keys[1])); !errors.Is(err, txpool.ErrFutureReplacePending) {
 		t.Fatalf("adding future replace transaction error mismatch: have %v, want %v", err, txpool.ErrFutureReplacePending)
 	}
 	pending, queued = pool.Stats()
@@ -2179,7 +2179,7 @@ func TestReplacement(t *testing.T) {
 	if err := pool.addRemoteSync(pricedTransaction(0, 100000, big.NewInt(1), key)); err != nil {
 		t.Fatalf("failed to add original cheap pending transaction: %v", err)
 	}
-	if err := pool.addRemote(pricedTransaction(0, 100001, big.NewInt(1), key)); err != txpool.ErrReplaceUnderpriced {
+	if err := pool.addRemote(pricedTransaction(0, 100001, big.NewInt(1), key)); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 		t.Fatalf("original cheap pending transaction replacement error mismatch: have %v, want %v", err, txpool.ErrReplaceUnderpriced)
 	}
 	if err := pool.addRemote(pricedTransaction(0, 100000, big.NewInt(2), key)); err != nil {
@@ -2192,7 +2192,7 @@ func TestReplacement(t *testing.T) {
 	if err := pool.addRemoteSync(pricedTransaction(0, 100000, big.NewInt(price), key)); err != nil {
 		t.Fatalf("failed to add original proper pending transaction: %v", err)
 	}
-	if err := pool.addRemote(pricedTransaction(0, 100001, big.NewInt(threshold-1), key)); err != txpool.ErrReplaceUnderpriced {
+	if err := pool.addRemote(pricedTransaction(0, 100001, big.NewInt(threshold-1), key)); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 		t.Fatalf("original proper pending transaction replacement error mismatch: have %v, want %v", err, txpool.ErrReplaceUnderpriced)
 	}
 	if err := pool.addRemote(pricedTransaction(0, 100000, big.NewInt(threshold), key)); err != nil {
@@ -2206,7 +2206,7 @@ func TestReplacement(t *testing.T) {
 	if err := pool.addRemote(pricedTransaction(2, 100000, big.NewInt(1), key)); err != nil {
 		t.Fatalf("failed to add original cheap queued transaction: %v", err)
 	}
-	if err := pool.addRemote(pricedTransaction(2, 100001, big.NewInt(1), key)); err != txpool.ErrReplaceUnderpriced {
+	if err := pool.addRemote(pricedTransaction(2, 100001, big.NewInt(1), key)); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 		t.Fatalf("original cheap queued transaction replacement error mismatch: have %v, want %v", err, txpool.ErrReplaceUnderpriced)
 	}
 	if err := pool.addRemote(pricedTransaction(2, 100000, big.NewInt(2), key)); err != nil {
@@ -2216,7 +2216,7 @@ func TestReplacement(t *testing.T) {
 	if err := pool.addRemote(pricedTransaction(2, 100000, big.NewInt(price), key)); err != nil {
 		t.Fatalf("failed to add original proper queued transaction: %v", err)
 	}
-	if err := pool.addRemote(pricedTransaction(2, 100001, big.NewInt(threshold-1), key)); err != txpool.ErrReplaceUnderpriced {
+	if err := pool.addRemote(pricedTransaction(2, 100001, big.NewInt(threshold-1), key)); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 		t.Fatalf("original proper queued transaction replacement error mismatch: have %v, want %v", err, txpool.ErrReplaceUnderpriced)
 	}
 	if err := pool.addRemote(pricedTransaction(2, 100000, big.NewInt(threshold), key)); err != nil {
@@ -2280,7 +2280,7 @@ func TestReplacementDynamicFee(t *testing.T) {
 		}
 		// 2.  Don't bump tip or feecap => discard
 		tx = dynamicFeeTx(nonce, 100001, big.NewInt(2), big.NewInt(1), key)
-		if err := pool.addRemote(tx); err != txpool.ErrReplaceUnderpriced {
+		if err := pool.addRemote(tx); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 			t.Fatalf("original cheap %s transaction replacement error mismatch: have %v, want %v", stage, err, txpool.ErrReplaceUnderpriced)
 		}
 		// 3.  Bump both more than min => accept
@@ -2303,22 +2303,22 @@ func TestReplacementDynamicFee(t *testing.T) {
 		}
 		// 6.  Bump tip max allowed so it's still underpriced => discard
 		tx = dynamicFeeTx(nonce, 100000, big.NewInt(gasFeeCap), big.NewInt(tipThreshold-1), key)
-		if err := pool.addRemote(tx); err != txpool.ErrReplaceUnderpriced {
+		if err := pool.addRemote(tx); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 			t.Fatalf("original proper %s transaction replacement error mismatch: have %v, want %v", stage, err, txpool.ErrReplaceUnderpriced)
 		}
 		// 7.  Bump fee cap max allowed so it's still underpriced => discard
 		tx = dynamicFeeTx(nonce, 100000, big.NewInt(feeCapThreshold-1), big.NewInt(gasTipCap), key)
-		if err := pool.addRemote(tx); err != txpool.ErrReplaceUnderpriced {
+		if err := pool.addRemote(tx); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 			t.Fatalf("original proper %s transaction replacement error mismatch: have %v, want %v", stage, err, txpool.ErrReplaceUnderpriced)
 		}
 		// 8.  Bump tip min for acceptance => accept
 		tx = dynamicFeeTx(nonce, 100000, big.NewInt(gasFeeCap), big.NewInt(tipThreshold), key)
-		if err := pool.addRemote(tx); err != txpool.ErrReplaceUnderpriced {
+		if err := pool.addRemote(tx); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 			t.Fatalf("original proper %s transaction replacement error mismatch: have %v, want %v", stage, err, txpool.ErrReplaceUnderpriced)
 		}
 		// 9.  Bump fee cap min for acceptance => accept
 		tx = dynamicFeeTx(nonce, 100000, big.NewInt(feeCapThreshold), big.NewInt(gasTipCap), key)
-		if err := pool.addRemote(tx); err != txpool.ErrReplaceUnderpriced {
+		if err := pool.addRemote(tx); !errors.Is(err, txpool.ErrReplaceUnderpriced) {
 			t.Fatalf("original proper %s transaction replacement error mismatch: have %v, want %v", stage, err, txpool.ErrReplaceUnderpriced)
 		}
 		// 10. Check events match expected (3 new executable txs during pending, 0 during queue)

core/types/transaction_test.go

@@ -75,7 +75,7 @@ func TestDecodeEmptyTypedTx(t *testing.T) {
 	input := []byte{0x80}
 	var tx Transaction
 	err := rlp.DecodeBytes(input, &tx)
-	if err != errShortTypedTx {
+	if !errors.Is(err, errShortTypedTx) {
 		t.Fatal("wrong error:", err)
 	}
 }
@@ -538,7 +538,7 @@ func TestYParityJSONUnmarshalling(t *testing.T) {
 				// Unmarshal the tx
 				var tx Transaction
 				err = tx.UnmarshalJSON(jsonBytes)
-				if err != test.wantErr {
+				if !errors.Is(err, test.wantErr) {
 					t.Fatalf("wrong error: got %v, want %v", err, test.wantErr)
 				}
 			})

core/vm/evm.go

@@ -17,6 +17,7 @@
 package vm
 
 import (
+	"github.com/pkg/errors"
 	"math/big"
 	"sync/atomic"
 
@@ -246,7 +247,7 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 	// when we're in homestead this also counts for code storage gas errors.
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != ErrExecutionReverted {
+		if !errors.Is(err, ErrExecutionReverted) {
 			gas = 0
 		}
 		// TODO: consider clearing up unused snapshots:
@@ -299,7 +300,7 @@ func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte,
 	}
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != ErrExecutionReverted {
+		if !errors.Is(err, ErrExecutionReverted) {
 			gas = 0
 		}
 	}
@@ -343,7 +344,7 @@ func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []by
 	}
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != ErrExecutionReverted {
+		if !errors.Is(err, ErrExecutionReverted) {
 			gas = 0
 		}
 	}
@@ -399,7 +400,7 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	}
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != ErrExecutionReverted {
+		if !errors.Is(err, ErrExecutionReverted) {
 			gas = 0
 		}
 	}
@@ -492,9 +493,9 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
 	// When an error was returned by the EVM or when setting the creation code
 	// above we revert to the snapshot and consume any gas remaining. Additionally
 	// when we're in homestead this also counts for code storage gas errors.
-	if err != nil && (evm.chainRules.IsHomestead || err != ErrCodeStoreOutOfGas) {
+	if err != nil && (evm.chainRules.IsHomestead || !errors.Is(err, ErrCodeStoreOutOfGas)) {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != ErrExecutionReverted {
+		if !errors.Is(err, ErrExecutionReverted) {
 			contract.UseGas(contract.Gas)
 		}
 	}

core/vm/gas_table_test.go

@@ -18,6 +18,8 @@ package vm
 
 import (
 	"bytes"
+	"errors"
+	"github.com/pkg/errors"
 	"math"
 	"math/big"
 	"sort"
@@ -43,8 +45,8 @@ func TestMemoryGasCost(t *testing.T) {
 	}
 	for i, tt := range tests {
 		v, err := memoryGasCost(&Memory{}, tt.size)
-		if (err == ErrGasUintOverflow) != tt.overflow {
+		if (errors.Is(err, ErrGasUintOverflow)) != tt.overflow {
-			t.Errorf("test %d: overflow mismatch: have %v, want %v", i, err == ErrGasUintOverflow, tt.overflow)
+			t.Errorf("test %d: overflow mismatch: have %v, want %v", i, errors.Is(err, ErrGasUintOverflow), tt.overflow)
 		}
 		if v != tt.cost {
 			t.Errorf("test %d: gas cost mismatch: have %v, want %v", i, v, tt.cost)
@@ -98,7 +100,7 @@ func TestEIP2200(t *testing.T) {
 		vmenv := NewEVM(vmctx, TxContext{}, statedb, params.AllEthashProtocolChanges, Config{ExtraEips: []int{2200}})
 
 		_, gas, err := vmenv.Call(AccountRef(common.Address{}), address, nil, tt.gaspool, new(uint256.Int))
-		if err != tt.failure {
+		if !errors.Is(err, tt.failure) {
 			t.Errorf("test %d: failure mismatch: have %v, want %v", i, err, tt.failure)
 		}
 		if used := tt.gaspool - gas; used != tt.used {

core/vm/instructions.go

@@ -17,6 +17,8 @@
 package vm
 
 import (
+	"errors"
+	"github.com/pkg/errors"
 	"math"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -597,9 +599,9 @@ func opCreate(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]b
 	// homestead we must check for CodeStoreOutOfGasError (homestead only
 	// rule) and treat as an error, if the ruleset is frontier we must
 	// ignore this error and pretend the operation was successful.
-	if interpreter.evm.chainRules.IsHomestead && suberr == ErrCodeStoreOutOfGas {
+	if interpreter.evm.chainRules.IsHomestead && errors.Is(suberr, ErrCodeStoreOutOfGas) {
 		stackvalue.Clear()
-	} else if suberr != nil && suberr != ErrCodeStoreOutOfGas {
+	} else if suberr != nil && !errors.Is(suberr, ErrCodeStoreOutOfGas) {
 		stackvalue.Clear()
 	} else {
 		stackvalue.SetBytes(addr.Bytes())
@@ -607,7 +609,7 @@ func opCreate(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]b
 	scope.Stack.push(&stackvalue)
 	scope.Contract.Gas += returnGas
 
-	if suberr == ErrExecutionReverted {
+	if errors.Is(suberr, ErrExecutionReverted) {
 		interpreter.returnData = res // set REVERT data to return data buffer
 		return res, nil
 	}
@@ -642,7 +644,7 @@ func opCreate2(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]
 	scope.Stack.push(&stackvalue)
 	scope.Contract.Gas += returnGas
 
-	if suberr == ErrExecutionReverted {
+	if errors.Is(suberr, ErrExecutionReverted) {
 		interpreter.returnData = res // set REVERT data to return data buffer
 		return res, nil
 	}
@@ -676,7 +678,7 @@ func opCall(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byt
 		temp.SetOne()
 	}
 	stack.push(&temp)
-	if err == nil || err == ErrExecutionReverted {
+	if err == nil || errors.Is(err, ErrExecutionReverted) {
 		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
 	scope.Contract.Gas += returnGas
@@ -708,7 +710,7 @@ func opCallCode(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([
 		temp.SetOne()
 	}
 	stack.push(&temp)
-	if err == nil || err == ErrExecutionReverted {
+	if err == nil || errors.Is(err, ErrExecutionReverted) {
 		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
 	scope.Contract.Gas += returnGas
@@ -736,7 +738,7 @@ func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext
 		temp.SetOne()
 	}
 	stack.push(&temp)
-	if err == nil || err == ErrExecutionReverted {
+	if err == nil || errors.Is(err, ErrExecutionReverted) {
 		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
 	scope.Contract.Gas += returnGas
@@ -764,7 +766,7 @@ func opStaticCall(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext)
 		temp.SetOne()
 	}
 	stack.push(&temp)
-	if err == nil || err == ErrExecutionReverted {
+	if err == nil || errors.Is(err, ErrExecutionReverted) {
 		scope.Memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
 	scope.Contract.Gas += returnGas

core/vm/interpreter.go

@@ -21,6 +21,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/pkg/errors"
 )
 
 // Config are the configuration options for the Interpreter
@@ -234,7 +235,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		pc++
 	}
 
-	if err == errStopToken {
+	if errors.Is(err, errStopToken) {
 		err = nil // clear stop token error
 	}
 

crypto/crypto_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"crypto/ecdsa"
 	"encoding/hex"
+	"github.com/pkg/errors"
 	"math/big"
 	"os"
 	"reflect"
@@ -66,11 +67,11 @@ func BenchmarkSha3(b *testing.B) {
 
 func TestUnmarshalPubkey(t *testing.T) {
 	key, err := UnmarshalPubkey(nil)
-	if err != errInvalidPubkey || key != nil {
+	if !errors.Is(err, errInvalidPubkey) || key != nil {
 		t.Fatalf("expected error, got %v, %v", err, key)
 	}
 	key, err = UnmarshalPubkey([]byte{1, 2, 3})
-	if err != errInvalidPubkey || key != nil {
+	if !errors.Is(err, errInvalidPubkey) || key != nil {
 		t.Fatalf("expected error, got %v, %v", err, key)
 	}
 

crypto/ecies/ecies_test.go

@@ -152,12 +152,12 @@ func TestTooBigSharedKey(t *testing.T) {
 	}
 
 	_, err = prv1.GenerateShared(&prv2.PublicKey, 32, 32)
-	if err != ErrSharedKeyTooBig {
+	if !errors.Is(err, ErrSharedKeyTooBig) {
 		t.Fatal("ecdh: shared key should be too large for curve")
 	}
 
 	_, err = prv2.GenerateShared(&prv1.PublicKey, 32, 32)
-	if err != ErrSharedKeyTooBig {
+	if !errors.Is(err, ErrSharedKeyTooBig) {
 		t.Fatal("ecdh: shared key should be too large for curve")
 	}
 }
@@ -355,7 +355,7 @@ func TestBasicKeyValidation(t *testing.T) {
 	for _, b := range badBytes {
 		ct[0] = b
 		_, err := prv.Decrypt(ct, nil, nil)
-		if err != ErrInvalidPublicKey {
+		if !errors.Is(err, ErrInvalidPublicKey) {
 			t.Fatal("ecies: validated an invalid key")
 		}
 	}

crypto/secp256k1/secp256_test.go

@@ -13,6 +13,7 @@ import (
 	"crypto/elliptic"
 	"crypto/rand"
 	"encoding/hex"
+	"errors"
 	"io"
 	"testing"
 )
@@ -92,7 +93,7 @@ func TestInvalidRecoveryID(t *testing.T) {
 	sig, _ := Sign(msg, seckey)
 	sig[64] = 99
 	_, err := RecoverPubkey(msg, sig)
-	if err != ErrInvalidRecoveryID {
+	if !errors.Is(err, ErrInvalidRecoveryID) {
 		t.Fatalf("got %q, want %q", err, ErrInvalidRecoveryID)
 	}
 }

eth/downloader/downloader.go

@@ -665,7 +665,7 @@ func (d *Downloader) spawnSync(fetchers []func() error) error {
 		}
 		if got := <-errc; got != nil {
 			err = got
-			if got != errCanceled {
+			if !errors.Is(got, errCanceled) {
 				break // receive a meaningful error, bubble it up
 			}
 		}
@@ -1547,7 +1547,7 @@ func (d *Downloader) processSnapSyncContent() error {
 	}()
 
 	closeOnErr := func(s *stateSync) {
-		if err := s.Wait(); err != nil && err != errCancelStateFetch && err != errCanceled && err != snap.ErrCancelled {
+		if err := s.Wait(); err != nil && !errors.Is(err, errCancelStateFetch) && !errors.Is(err, errCanceled) && !errors.Is(err, snap.ErrCancelled) {
 			d.queue.Close() // wake up Results
 		}
 	}

eth/downloader/downloader_test.go

@@ -17,7 +17,9 @@
 package downloader
 
 import (
+	"errors"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/big"
 	"os"
 	"strings"
@@ -614,7 +616,7 @@ func testBoundedForkedSync(t *testing.T, protocol uint, mode SyncMode) {
 	assertOwnChain(t, tester, len(chainA.blocks))
 
 	// Synchronise with the second peer and ensure that the fork is rejected to being too old
-	if err := tester.sync("rewriter", nil, mode); err != errInvalidAncestor {
+	if err := tester.sync("rewriter", nil, mode); !errors.Is(err, errInvalidAncestor) {
 		t.Fatalf("sync failure mismatch: have %v, want %v", err, errInvalidAncestor)
 	}
 }
@@ -649,7 +651,7 @@ func testBoundedHeavyForkedSync(t *testing.T, protocol uint, mode SyncMode) {
 
 	tester.newPeer("heavy-rewriter", protocol, chainB.blocks[1:])
 	// Synchronise with the second peer and ensure that the fork is rejected to being too old
-	if err := tester.sync("heavy-rewriter", nil, mode); err != errInvalidAncestor {
+	if err := tester.sync("heavy-rewriter", nil, mode); !errors.Is(err, errInvalidAncestor) {
 		t.Fatalf("sync failure mismatch: have %v, want %v", err, errInvalidAncestor)
 	}
 }
@@ -854,7 +856,7 @@ func testHighTDStarvationAttack(t *testing.T, protocol uint, mode SyncMode) {
 
 	chain := testChainBase.shorten(1)
 	tester.newPeer("attack", protocol, chain.blocks[1:])
-	if err := tester.sync("attack", big.NewInt(1000000), mode); err != errStallingPeer {
+	if err := tester.sync("attack", big.NewInt(1000000), mode); !errors.Is(err, errStallingPeer) {
 		t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errStallingPeer)
 	}
 }

eth/downloader/skeleton.go

@@ -278,25 +278,25 @@ func (s *skeleton) startup() {
 				// signalling as the sync loop should never terminate (TM).
 				newhead, err := s.sync(head)
 				switch {
-				case err == errSyncLinked:
+				case errors.Is(err, errSyncLinked):
 					// Sync cycle linked up to the genesis block, or the existent chain
 					// segment. Tear down the loop and restart it so, it can properly
 					// notify the backfiller. Don't account a new head.
 					head = nil
 
-				case err == errSyncMerged:
+				case errors.Is(err, errSyncMerged):
 					// Subchains were merged, we just need to reinit the internal
 					// start to continue on the tail of the merged chain. Don't
 					// announce a new head,
 					head = nil
 
-				case err == errSyncReorged:
+				case errors.Is(err, errSyncReorged):
 					// The subchain being synced got modified at the head in a
 					// way that requires resyncing it. Restart sync with the new
 					// head to force a cleanup.
 					head = newhead
 
-				case err == errTerminated:
+				case errors.Is(err, errTerminated):
 					// Sync was requested to be terminated from within, stop and
 					// return (no need to pass a message, was already done internally)
 					return

eth/filters/filter_system_test.go

@@ -478,7 +478,7 @@ func TestInvalidGetRangeLogsRequest(t *testing.T) {
 		api    = NewFilterAPI(sys, false)
 	)
 
-	if _, err := api.GetLogs(context.Background(), FilterCriteria{FromBlock: big.NewInt(2), ToBlock: big.NewInt(1)}); err != errInvalidBlockRange {
+	if _, err := api.GetLogs(context.Background(), FilterCriteria{FromBlock: big.NewInt(2), ToBlock: big.NewInt(1)}); !errors.Is(err, errInvalidBlockRange) {
 		t.Errorf("Expected Logs for invalid range return error, but got: %v", err)
 	}
 }

eth/filters/filter_test.go

@@ -19,6 +19,7 @@ package filters
 import (
 	"context"
 	"encoding/json"
+	"github.com/pkg/errors"
 	"math/big"
 	"strings"
 	"testing"
@@ -382,7 +383,7 @@ func TestFilters(t *testing.T) {
 		if err == nil {
 			t.Fatal("expected error")
 		}
-		if err != context.DeadlineExceeded {
+		if !errors.Is(err, context.DeadlineExceeded) {
 			t.Fatalf("expected context.DeadlineExceeded, got %v", err)
 		}
 	})

eth/gasprice/feehistory_test.go

@@ -84,7 +84,7 @@ func TestFeeHistory(t *testing.T) {
 		if len(ratio) != c.expCount {
 			t.Fatalf("Test case %d: gasUsedRatio array length mismatch, want %d, got %d", i, c.expCount, len(ratio))
 		}
-		if err != c.expErr && !errors.Is(err, c.expErr) {
+		if !errors.Is(err, c.expErr) && !errors.Is(err, c.expErr) {
 			t.Fatalf("Test case %d: error mismatch, want %v, got %v", i, c.expErr, err)
 		}
 	}

eth/tracers/logger/logger.go

@@ -20,6 +20,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"github.com/pkg/errors"
 	"io"
 	"math/big"
 	"strings"
@@ -245,7 +246,7 @@ func (l *StructLogger) GetResult() (json.RawMessage, error) {
 	returnData := common.CopyBytes(l.output)
 	// Return data when successful and revert reason when reverted, otherwise empty.
 	returnVal := fmt.Sprintf("%x", returnData)
-	if failed && l.err != vm.ErrExecutionReverted {
+	if failed && !errors.Is(l.err, vm.ErrExecutionReverted) {
 		returnVal = ""
 	}
 	return json.Marshal(&ExecutionResult{

ethclient/ethclient_test.go

@@ -398,7 +398,7 @@ func testTransactionInBlock(t *testing.T, client *rpc.Client) {
 	}
 
 	// Test tx in block not found.
-	if _, err := ec.TransactionInBlock(context.Background(), block.Hash(), 20); err != ethereum.NotFound {
+	if _, err := ec.TransactionInBlock(context.Background(), block.Hash(), 20); !errors.Is(err, ethereum.NotFound) {
 		t.Fatal("error should be ethereum.NotFound")
 	}
 

ethdb/pebble/pebble.go

@@ -19,7 +19,9 @@ package pebble
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
+	"github.com/pkg/errors"
 	"runtime"
 	"sync"
 	"sync/atomic"
@@ -279,7 +281,7 @@ func (d *Database) Has(key []byte) (bool, error) {
 		return false, pebble.ErrClosed
 	}
 	_, closer, err := d.db.Get(key)
-	if err == pebble.ErrNotFound {
+	if errors.Is(err, pebble.ErrNotFound) {
 		return false, nil
 	} else if err != nil {
 		return false, err
@@ -362,7 +364,7 @@ func (d *Database) NewSnapshot() (ethdb.Snapshot, error) {
 func (snap *snapshot) Has(key []byte) (bool, error) {
 	_, closer, err := snap.db.Get(key)
 	if err != nil {
-		if err != pebble.ErrNotFound {
+		if !errors.Is(err, pebble.ErrNotFound) {
 			return false, err
 		} else {
 			return false, nil

event/event_test.go

@@ -17,6 +17,7 @@
 package event
 
 import (
+	"github.com/pkg/errors"
 	"math/rand"
 	"sync"
 	"testing"
@@ -59,7 +60,7 @@ func TestMuxErrorAfterStop(t *testing.T) {
 	if _, isopen := <-sub.Chan(); isopen {
 		t.Errorf("subscription channel was not closed")
 	}
-	if err := mux.Post(testEvent(0)); err != ErrMuxClosed {
+	if err := mux.Post(testEvent(0)); !errors.Is(err, ErrMuxClosed) {
 		t.Errorf("Post error mismatch, got: %s, expected: %s", err, ErrMuxClosed)
 	}
 }

event/subscription_test.go

@@ -56,7 +56,7 @@ loop:
 				t.Fatalf("wrong int %d, want %d", got, want)
 			}
 		case err := <-sub.Err():
-			if err != errInts {
+			if !errors.Is(err, errInts) {
 				t.Fatalf("wrong error: got %q, want %q", err, errInts)
 			}
 			if want != 2 {

internal/build/util.go

@@ -21,6 +21,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
+	"github.com/pkg/errors"
 	"go/parser"
 	"go/token"
 	"io"
@@ -98,7 +99,7 @@ func RunGit(args ...string) string {
 	var stdout, stderr bytes.Buffer
 	cmd.Stdout, cmd.Stderr = &stdout, &stderr
 	if err := cmd.Run(); err != nil {
-		if e, ok := err.(*exec.Error); ok && e.Err == exec.ErrNotFound {
+		if e, ok := err.(*exec.Error); ok && errors.Is(e.Err, exec.ErrNotFound) {
 			if !warnedAboutGit {
 				log.Println("Warning: can't find 'git' in PATH")
 				warnedAboutGit = true

node/node_test.go

@@ -55,7 +55,7 @@ func TestNodeCloseMultipleTimes(t *testing.T) {
 
 	// Ensure that a stopped node can be stopped again
 	for i := 0; i < 3; i++ {
-		if err := stack.Close(); err != ErrNodeStopped {
+		if err := stack.Close(); !errors.Is(err, ErrNodeStopped) {
 			t.Fatalf("iter %d: stop failure mismatch: have %v, want %v", i, err, ErrNodeStopped)
 		}
 	}
@@ -71,14 +71,14 @@ func TestNodeStartMultipleTimes(t *testing.T) {
 	if err := stack.Start(); err != nil {
 		t.Fatalf("failed to start node: %v", err)
 	}
-	if err := stack.Start(); err != ErrNodeRunning {
+	if err := stack.Start(); !errors.Is(err, ErrNodeRunning) {
 		t.Fatalf("start failure mismatch: have %v, want %v ", err, ErrNodeRunning)
 	}
 	// Ensure that a node can be stopped, but only once
 	if err := stack.Close(); err != nil {
 		t.Fatalf("failed to stop node: %v", err)
 	}
-	if err := stack.Close(); err != ErrNodeStopped {
+	if err := stack.Close(); !errors.Is(err, ErrNodeStopped) {
 		t.Fatalf("stop failure mismatch: have %v, want %v ", err, ErrNodeStopped)
 	}
 }
@@ -100,7 +100,7 @@ func TestNodeUsedDataDir(t *testing.T) {
 
 	// Create a second node based on the same data directory and ensure failure
 	_, err = New(&Config{DataDir: dir})
-	if err != ErrDatadirUsed {
+	if !errors.Is(err, ErrDatadirUsed) {
 		t.Fatalf("duplicate datadir failure mismatch: have %v, want %v", err, ErrDatadirUsed)
 	}
 }
@@ -296,7 +296,7 @@ func TestLifecycleStartupError(t *testing.T) {
 	stack.RegisterLifecycle(failer)
 
 	// Start the protocol stack and ensure all started services stop
-	if err := stack.Start(); err != failure {
+	if err := stack.Start(); !errors.Is(err, failure) {
 		t.Fatalf("stack startup failure mismatch: have %v, want %v", err, failure)
 	}
 	for id := range lifecycles {
@@ -364,7 +364,7 @@ func TestLifecycleTerminationGuarantee(t *testing.T) {
 		t.Fatalf("termination failure mismatch: have %v, want StopError", err)
 	} else {
 		failer := reflect.TypeOf(&InstrumentedService{})
-		if err.Services[failer] != failure {
+		if !errors.Is(failure, err.Services[failer]) {
 			t.Fatalf("failer termination failure mismatch: have %v, want %v", err.Services[failer], failure)
 		}
 		if len(err.Services) != 1 {

node/rpcstack.go

@@ -281,7 +281,7 @@ func (h *httpServer) doStop() {
 	ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
 	defer cancel()
 	err := h.server.Shutdown(ctx)
-	if err != nil && err == ctx.Err() {
+	if err != nil && errors.Is(err, ctx.Err()) {
 		h.log.Warn("HTTP server graceful shutdown timed out")
 		h.server.Close()
 	}

p2p/discover/v4_udp_test.go

@@ -100,7 +100,7 @@ func (test *udpTest) packetInFrom(wantError error, key *ecdsa.PrivateKey, addr *
 		test.t.Errorf("%s encode error: %v", data.Name(), err)
 	}
 	test.sent = append(test.sent, enc)
-	if err = test.udp.handlePacket(addr, enc); err != wantError {
+	if err = test.udp.handlePacket(addr, enc); !errors.Is(err, wantError) {
 		test.t.Errorf("error mismatch: got %q, want %q", err, wantError)
 	}
 }

p2p/discover/v5_udp_test.go

@@ -21,6 +21,7 @@ import (
 	"crypto/ecdsa"
 	"encoding/binary"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/rand"
 	"net"
 	"reflect"
@@ -239,7 +240,7 @@ func TestUDPv5_pingCall(t *testing.T) {
 		done <- err
 	}()
 	test.waitPacketOut(func(p *v5wire.Ping, addr *net.UDPAddr, _ v5wire.Nonce) {})
-	if err := <-done; err != errTimeout {
+	if err := <-done; !errors.Is(err, errTimeout) {
 		t.Fatalf("want errTimeout, got %q", err)
 	}
 

p2p/discover/v5wire/encoding.go

@@ -128,7 +128,7 @@ var (
 // returns false, it is pretty certain that the packet causing the error does not belong
 // to discv5.
 func IsInvalidHeader(err error) bool {
-	return err == errTooShort || err == errInvalidHeader || err == errMsgTooShort
+	return errors.Is(err, errTooShort) || errors.Is(err, errInvalidHeader) || errors.Is(err, errMsgTooShort)
 }
 
 // Packet sizes.

p2p/dnsdisc/client_test.go

@@ -94,7 +94,7 @@ func TestClientSyncTreeBadNode(t *testing.T) {
 	c := NewClient(Config{Resolver: r, Logger: testlog.Logger(t, log.LvlTrace)})
 	_, err := c.SyncTree("enrtree://AKPYQIUQIL7PSIACI32J7FGZW56E5FKHEFCCOFHILBIMW3M6LWXS2@n")
 	wantErr := nameError{name: "INDMVBZEEQ4ESVYAKGIYU74EAA.n", err: entryError{typ: "enr", err: errInvalidENR}}
-	if err != wantErr {
+	if !errors.Is(wantErr, err) {
 		t.Fatalf("expected sync error %q, got %q", wantErr, err)
 	}
 }

p2p/dnsdisc/tree_test.go

@@ -17,6 +17,8 @@
 package dnsdisc
 
 import (
+	"errors"
+	"github.com/pkg/errors"
 	"reflect"
 	"testing"
 
@@ -54,7 +56,7 @@ func TestParseRoot(t *testing.T) {
 		if !reflect.DeepEqual(e, test.e) {
 			t.Errorf("test %d: wrong entry %s, want %s", i, spew.Sdump(e), spew.Sdump(test.e))
 		}
-		if err != test.err {
+		if !errors.Is(err, test.err) {
 			t.Errorf("test %d: wrong error %q, want %q", i, err, test.err)
 		}
 	}
@@ -131,7 +133,7 @@ func TestParseEntry(t *testing.T) {
 		if !reflect.DeepEqual(e, test.e) {
 			t.Errorf("test %d: wrong entry %s, want %s", i, spew.Sdump(e), spew.Sdump(test.e))
 		}
-		if err != test.err {
+		if !errors.Is(err, test.err) {
 			t.Errorf("test %d: wrong error %q, want %q", i, err, test.err)
 		}
 	}

p2p/enr/enr.go

@@ -228,13 +228,13 @@ func decodeRecord(s *rlp.Stream) (dec Record, raw []byte, err error) {
 		return dec, raw, err
 	}
 	if err = s.Decode(&dec.signature); err != nil {
-		if err == rlp.EOL {
+		if errors.Is(err, rlp.EOL) {
 			err = errIncompleteList
 		}
 		return dec, raw, err
 	}
 	if err = s.Decode(&dec.seq); err != nil {
-		if err == rlp.EOL {
+		if errors.Is(err, rlp.EOL) {
 			err = errIncompleteList
 		}
 		return dec, raw, err
@@ -244,13 +244,13 @@ func decodeRecord(s *rlp.Stream) (dec Record, raw []byte, err error) {
 	for i := 0; ; i++ {
 		var kv pair
 		if err := s.Decode(&kv.k); err != nil {
-			if err == rlp.EOL {
+			if errors.Is(err, rlp.EOL) {
 				break
 			}
 			return dec, raw, err
 		}
 		if err := s.Decode(&kv.v); err != nil {
-			if err == rlp.EOL {
+			if errors.Is(err, rlp.EOL) {
 				return dec, raw, errIncompletePair
 			}
 			return dec, raw, err

p2p/enr/enr_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/rand"
 	"testing"
 	"time"
@@ -149,7 +150,7 @@ func TestSortedGetAndSet(t *testing.T) {
 func TestDirty(t *testing.T) {
 	var r Record
 
-	if _, err := rlp.EncodeToBytes(r); err != errEncodeUnsigned {
+	if _, err := rlp.EncodeToBytes(r); !errors.Is(err, errEncodeUnsigned) {
 		t.Errorf("expected errEncodeUnsigned, got %#v", err)
 	}
 
@@ -164,7 +165,7 @@ func TestDirty(t *testing.T) {
 	if len(r.signature) != 0 {
 		t.Error("signature still set after modification")
 	}
-	if _, err := rlp.EncodeToBytes(r); err != errEncodeUnsigned {
+	if _, err := rlp.EncodeToBytes(r); !errors.Is(err, errEncodeUnsigned) {
 		t.Errorf("expected errEncodeUnsigned, got %#v", err)
 	}
 }
@@ -248,7 +249,7 @@ func TestRecordTooBig(t *testing.T) {
 
 	// set a big value for random key, expect error
 	r.Set(WithEntry(key, randomString(SizeLimit)))
-	if err := signTest([]byte{5}, &r); err != errTooBig {
+	if err := signTest([]byte{5}, &r); !errors.Is(err, errTooBig) {
 		t.Fatalf("expected to get errTooBig, got %#v", err)
 	}
 
@@ -274,7 +275,7 @@ func TestDecodeIncomplete(t *testing.T) {
 	for _, test := range tests {
 		var r Record
 		err := rlp.DecodeBytes(test.input, &r)
-		if err != test.err {
+		if !errors.Is(err, test.err) {
 			t.Errorf("wrong error for %X: %v", test.input, err)
 		}
 	}

p2p/enr/entries.go

@@ -175,7 +175,7 @@ type KeyError struct {
 
 // Error implements error.
 func (err *KeyError) Error() string {
-	if err.Err == errNotFound {
+	if errors.Is(err.Err, errNotFound) {
 		return fmt.Sprintf("missing ENR key %q", err.Key)
 	}
 	return fmt.Sprintf("ENR key %q: %v", err.Key, err.Err)
@@ -190,7 +190,7 @@ func (err *KeyError) Unwrap() error {
 func IsNotFound(err error) bool {
 	var ke *KeyError
 	if errors.As(err, &ke) {
-		return ke.Err == errNotFound
+		return errors.Is(ke.Err, errNotFound)
 	}
 	return false
 }

p2p/message_test.go

@@ -19,6 +19,7 @@ package p2p
 import (
 	"bytes"
 	"fmt"
+	"github.com/pkg/errors"
 	"io"
 	"runtime"
 	"testing"
@@ -55,7 +56,7 @@ loop:
 		go func() {
 			if err := SendItems(rw1, 1); err == nil {
 				t.Error("EncodeMsg returned nil error")
-			} else if err != ErrPipeClosed {
+			} else if !errors.Is(err, ErrPipeClosed) {
 				t.Errorf("EncodeMsg returned wrong error: got %v, want %v", err, ErrPipeClosed)
 			}
 			close(done)

p2p/netutil/net_test.go

@@ -18,6 +18,7 @@ package netutil
 
 import (
 	"fmt"
+	"github.com/pkg/errors"
 	"net"
 	"reflect"
 	"testing"
@@ -160,7 +161,7 @@ func TestCheckRelayIP(t *testing.T) {
 
 	for _, test := range tests {
 		err := CheckRelayIP(parseIP(test.sender), parseIP(test.addr))
-		if err != test.want {
+		if !errors.Is(err, test.want) {
 			t.Errorf("%s from %s: got %q, want %q", test.addr, test.sender, err, test.want)
 		}
 	}

p2p/peer_test.go

@@ -138,7 +138,7 @@ func TestPeerProtoReadMsg(t *testing.T) {
 
 	select {
 	case err := <-errc:
-		if err != errProtocolReturned {
+		if !errors.Is(err, errProtocolReturned) {
 			t.Errorf("peer returned error: %v", err)
 		}
 	case <-time.After(2 * time.Second):
@@ -190,7 +190,7 @@ func TestPeerDisconnect(t *testing.T) {
 	}
 	select {
 	case reason := <-disc:
-		if reason != DiscQuitting {
+		if !errors.Is(reason, DiscQuitting) {
 			t.Errorf("run returned wrong reason: got %v, want %v", reason, DiscQuitting)
 		}
 	case <-time.After(500 * time.Millisecond):

p2p/server_test.go

@@ -280,7 +280,7 @@ func TestServerAtCap(t *testing.T) {
 	// Try inserting a non-trusted connection.
 	anotherID := randomID()
 	c := newconn(anotherID)
-	if err := srv.checkpoint(c, srv.checkpointPostHandshake); err != DiscTooManyPeers {
+	if err := srv.checkpoint(c, srv.checkpointPostHandshake); !errors.Is(err, DiscTooManyPeers) {
 		t.Error("wrong error for insert:", err)
 	}
 	// Try inserting a trusted connection.
@@ -295,7 +295,7 @@ func TestServerAtCap(t *testing.T) {
 	// Remove from trusted set and try again
 	srv.RemoveTrustedPeer(newNode(trustedID, ""))
 	c = newconn(trustedID)
-	if err := srv.checkpoint(c, srv.checkpointPostHandshake); err != DiscTooManyPeers {
+	if err := srv.checkpoint(c, srv.checkpointPostHandshake); !errors.Is(err, DiscTooManyPeers) {
 		t.Error("wrong error for insert:", err)
 	}
 
@@ -345,7 +345,7 @@ func TestServerPeerLimits(t *testing.T) {
 	dialDest := clientnode
 	conn, _ := net.Pipe()
 	srv.SetupConn(conn, flags, dialDest)
-	if tp.closeErr != DiscTooManyPeers {
+	if !errors.Is(tp.closeErr, DiscTooManyPeers) {
 		t.Errorf("unexpected close error: %q", tp.closeErr)
 	}
 	conn.Close()
@@ -355,11 +355,11 @@ func TestServerPeerLimits(t *testing.T) {
 	// Check that server allows a trusted peer despite being full.
 	conn, _ = net.Pipe()
 	srv.SetupConn(conn, flags, dialDest)
-	if tp.closeErr == DiscTooManyPeers {
+	if errors.Is(tp.closeErr, DiscTooManyPeers) {
 		t.Errorf("failed to bypass MaxPeers with trusted node: %q", tp.closeErr)
 	}
 
-	if tp.closeErr != DiscUselessPeer {
+	if !errors.Is(tp.closeErr, DiscUselessPeer) {
 		t.Errorf("unexpected close error: %q", tp.closeErr)
 	}
 	conn.Close()
@@ -369,7 +369,7 @@ func TestServerPeerLimits(t *testing.T) {
 	// Check that server is full again.
 	conn, _ = net.Pipe()
 	srv.SetupConn(conn, flags, dialDest)
-	if tp.closeErr != DiscTooManyPeers {
+	if !errors.Is(tp.closeErr, DiscTooManyPeers) {
 		t.Errorf("unexpected close error: %q", tp.closeErr)
 	}
 	conn.Close()

p2p/transport.go

@@ -114,7 +114,7 @@ func (t *rlpxTransport) close(err error) {
 	// We only bother doing this if the underlying connection supports
 	// setting a timeout tough.
 	if t.conn != nil {
-		if r, ok := err.(DiscReason); ok && r != DiscNetworkError {
+		if r, ok := err.(DiscReason); ok && !errors.Is(r, DiscNetworkError) {
 			deadline := time.Now().Add(discWriteTimeout)
 			if err := t.conn.SetWriteDeadline(deadline); err == nil {
 				// Connection supports write deadline.

rlp/decode.go

@@ -326,7 +326,7 @@ func decodeSliceElems(s *Stream, val reflect.Value, elemdec decoder) error {
 			val.SetLen(i + 1)
 		}
 		// decode into element
-		if err := elemdec(s, val.Index(i)); err == EOL {
+		if err := elemdec(s, val.Index(i)); errors.Is(err, EOL) {
 			break
 		} else if err != nil {
 			return addErrorContext(err, fmt.Sprint("[", i, "]"))
@@ -345,7 +345,7 @@ func decodeListArray(s *Stream, val reflect.Value, elemdec decoder) error {
 	vlen := val.Len()
 	i := 0
 	for ; i < vlen; i++ {
-		if err := elemdec(s, val.Index(i)); err == EOL {
+		if err := elemdec(s, val.Index(i)); errors.Is(err, EOL) {
 			break
 		} else if err != nil {
 			return addErrorContext(err, fmt.Sprint("[", i, "]"))
@@ -417,7 +417,7 @@ func makeStructDecoder(typ reflect.Type) (decoder, error) {
 		}
 		for i, f := range fields {
 			err := f.info.decoder(s, val.Field(f.index))
-			if err == EOL {
+			if errors.Is(err, EOL) {
 				if f.optional {
 					// The field is optional, so reaching the end of the list before
 					// reaching the last field is acceptable. All remaining undecoded
@@ -757,7 +757,7 @@ func (s *Stream) uint(maxbits int) (uint64, error) {
 		}
 		v, err := s.readUint(byte(size))
 		switch {
-		case err == ErrCanonSize:
+		case errors.Is(err, ErrCanonSize):
 			// Adjust error because we're not reading a size right now.
 			return 0, ErrCanonInt
 		case err != nil:

rlp/decode_test.go

@@ -250,7 +250,7 @@ func TestStreamList(t *testing.T) {
 		}
 	}
 
-	if _, err := s.Uint(); err != EOL {
+	if _, err := s.Uint(); !errors.Is(err, EOL) {
 		t.Errorf("Uint error mismatch, got %v, want %v", err, EOL)
 	}
 	if err = s.ListEnd(); err != nil {
@@ -331,16 +331,16 @@ func TestStreamReadBytes(t *testing.T) {
 func TestDecodeErrors(t *testing.T) {
 	r := bytes.NewReader(nil)
 
-	if err := Decode(r, nil); err != errDecodeIntoNil {
+	if err := Decode(r, nil); !errors.Is(err, errDecodeIntoNil) {
 		t.Errorf("Decode(r, nil) error mismatch, got %q, want %q", err, errDecodeIntoNil)
 	}
 
 	var nilptr *struct{}
-	if err := Decode(r, nilptr); err != errDecodeIntoNil {
+	if err := Decode(r, nilptr); !errors.Is(err, errDecodeIntoNil) {
 		t.Errorf("Decode(r, nilptr) error mismatch, got %q, want %q", err, errDecodeIntoNil)
 	}
 
-	if err := Decode(r, struct{}{}); err != errNoPointer {
+	if err := Decode(r, struct{}{}); !errors.Is(err, errNoPointer) {
 		t.Errorf("Decode(r, struct{}{}) error mismatch, got %q, want %q", err, errNoPointer)
 	}
 

rlp/raw_test.go

@@ -129,7 +129,7 @@ func TestSplitUint64(t *testing.T) {
 		if !bytes.Equal(rest, unhex(test.rest)) {
 			t.Errorf("test %d: rest mismatch: got %x, want %s (input %q)", i, rest, test.rest, test.input)
 		}
-		if err != test.err {
+		if !errors.Is(err, test.err) {
 			t.Errorf("test %d: error mismatch: got %q, want %q", i, err, test.err)
 		}
 	}
@@ -213,7 +213,7 @@ func TestSplit(t *testing.T) {
 		if !bytes.Equal(rest, unhex(test.rest)) {
 			t.Errorf("test %d: rest mismatch: got %x, want %s", i, rest, test.rest)
 		}
-		if err != test.err {
+		if !errors.Is(err, test.err) {
 			t.Errorf("test %d: error mismatch: got %q, want %q", i, err, test.err)
 		}
 	}
@@ -251,7 +251,7 @@ func TestReadSize(t *testing.T) {
 
 	for _, test := range tests {
 		size, err := readSize(unhex(test.input), test.slen)
-		if err != test.err {
+		if !errors.Is(err, test.err) {
 			t.Errorf("readSize(%s, %d): error mismatch: got %q, want %q", test.input, test.slen, err, test.err)
 			continue
 		}

rpc/client_test.go

@@ -211,7 +211,7 @@ func TestClientBatchRequest_len(t *testing.T) {
 			}
 		}
 		for i, elem := range batch[2:] {
-			if elem.Error != ErrMissingBatchResponse {
+			if !errors.Is(elem.Error, ErrMissingBatchResponse) {
 				t.Errorf("wrong error %q for batch element %d", elem.Error, i+2)
 			}
 		}
@@ -239,7 +239,7 @@ func TestClientBatchRequest_len(t *testing.T) {
 			}
 		}
 		for i, elem := range batch[1:] {
-			if elem.Error != ErrMissingBatchResponse {
+			if !errors.Is(elem.Error, ErrMissingBatchResponse) {
 				t.Errorf("wrong error %q for batch element %d", elem.Error, i+2)
 			}
 		}
@@ -277,7 +277,7 @@ func TestClientBatchRequestLimit(t *testing.T) {
 
 	// Check that remaining response batch elements are reported as absent.
 	for i, elem := range batch[1:] {
-		if elem.Error != ErrMissingBatchResponse {
+		if !errors.Is(elem.Error, ErrMissingBatchResponse) {
 			t.Fatalf("batch elem %d has unexpected error: %v", i+1, elem.Error)
 		}
 	}
@@ -633,7 +633,7 @@ func TestClientNotificationStorm(t *testing.T) {
 					t.Fatalf("(%d/%d) unexpected value %d", i, count, val)
 				}
 			case err := <-sub.Err():
-				if wantError && err != ErrSubscriptionQueueOverflow {
+				if wantError && !errors.Is(err, ErrSubscriptionQueueOverflow) {
 					t.Fatalf("(%d/%d) got error %q, want %q", i, count, err, ErrSubscriptionQueueOverflow)
 				} else if !wantError {
 					t.Fatalf("(%d/%d) got unexpected error %q", i, count, err)

rpc/http_test.go

@@ -19,6 +19,7 @@ package rpc
 import (
 	"context"
 	"fmt"
+	"github.com/pkg/errors"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -234,12 +235,12 @@ func TestNewContextWithHeaders(t *testing.T) {
 	ctx3 := NewContextWithHeaders(ctx2, newHdr("key-2", "val-2"))
 
 	expectedHeaders = 3
-	if err := client.CallContext(ctx3, nil, "test"); err != ErrNoResult {
+	if err := client.CallContext(ctx3, nil, "test"); !errors.Is(err, ErrNoResult) {
 		t.Error("call failed", err)
 	}
 
 	expectedHeaders = 2
-	if err := client.CallContext(ctx2, nil, "test"); err != ErrNoResult {
+	if err := client.CallContext(ctx2, nil, "test"); !errors.Is(err, ErrNoResult) {
 		t.Error("call failed:", err)
 	}
 }

rpc/subscription.go

@@ -304,7 +304,7 @@ func (sub *ClientSubscription) run() {
 
 	// Send the error.
 	if err != nil {
-		if err == ErrClientQuit {
+		if errors.Is(err, ErrClientQuit) {
 			// ErrClientQuit gets here when Client.Close is called. This is reported as a
 			// nil error because it's not an error, but we can't close sub.err here.
 			err = nil
@@ -340,7 +340,7 @@ func (sub *ClientSubscription) forward() (unsubscribeServer bool, err error) {
 			if !recv.IsNil() {
 				err = recv.Interface().(error)
 			}
-			if err == errUnsubscribed {
+			if errors.Is(err, errUnsubscribed) {
 				// Exiting because Unsubscribe was called, unsubscribe on server.
 				return true, nil
 			}

rpc/websocket_test.go

@@ -159,7 +159,7 @@ func TestWebsocketLargeRead(t *testing.T) {
 		// Check over limit
 		if overLimit > 0 {
 			err = client.Call(&res, "test_repeat", "A", expLimit+1)
-			if err == nil || err != websocket.ErrReadLimit {
+			if err == nil || !errors.Is(err, websocket.ErrReadLimit) {
 				t.Fatalf("wrong error with limit %d: %v expecting %v", expLimit, err, websocket.ErrReadLimit)
 			}
 		}

signer/core/api.go

@@ -332,7 +332,7 @@ func (api *SignerAPI) startUSBListener() {
 	for _, wallet := range am.Wallets() {
 		if err := wallet.Open(""); err != nil {
 			log.Warn("Failed to open wallet", "url", wallet.URL(), "err", err)
-			if err == usbwallet.ErrTrezorPINNeeded {
+			if errors.Is(err, usbwallet.ErrTrezorPINNeeded) {
 				go api.openTrezor(wallet.URL())
 			}
 		}
@@ -348,7 +348,7 @@ func (api *SignerAPI) derivationLoop(events chan accounts.WalletEvent) {
 		case accounts.WalletArrived:
 			if err := event.Wallet.Open(""); err != nil {
 				log.Warn("New wallet appeared, failed to open", "url", event.Wallet.URL(), "err", err)
-				if err == usbwallet.ErrTrezorPINNeeded {
+				if errors.Is(err, usbwallet.ErrTrezorPINNeeded) {
 					go api.openTrezor(event.Wallet.URL())
 				}
 			}

signer/core/api_test.go

@@ -19,7 +19,9 @@ package core_test
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/big"
 	"os"
 	"path/filepath"
@@ -155,7 +157,7 @@ func failCreateAccountWithPassword(ui *headlessUi, api *core.SignerAPI, password
 func failCreateAccount(ui *headlessUi, api *core.SignerAPI, t *testing.T) {
 	ui.approveCh <- "N"
 	addr, err := api.New(context.Background())
-	if err != core.ErrRequestDenied {
+	if !errors.Is(err, core.ErrRequestDenied) {
 		t.Fatal(err)
 	}
 	if addr != (common.Address{}) {
@@ -212,7 +214,7 @@ func TestNewAcc(t *testing.T) {
 	if len(list) != 0 {
 		t.Fatalf("List should be empty")
 	}
-	if err != core.ErrRequestDenied {
+	if !errors.Is(err, core.ErrRequestDenied) {
 		t.Fatal("Expected deny")
 	}
 }
@@ -264,7 +266,7 @@ func TestSignTx(t *testing.T) {
 	if res != nil {
 		t.Errorf("Expected nil-response, got %v", res)
 	}
-	if err != keystore.ErrDecrypt {
+	if !errors.Is(err, keystore.ErrDecrypt) {
 		t.Errorf("Expected ErrLocked! %v", err)
 	}
 	control.approveCh <- "No way"
@@ -272,7 +274,7 @@ func TestSignTx(t *testing.T) {
 	if res != nil {
 		t.Errorf("Expected nil-response, got %v", res)
 	}
-	if err != core.ErrRequestDenied {
+	if !errors.Is(err, core.ErrRequestDenied) {
 		t.Errorf("Expected ErrRequestDenied! %v", err)
 	}
 	// Sign with correct password

signer/core/signed_data_test.go

@@ -21,6 +21,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/pkg/errors"
 	"math/big"
 	"os"
 	"path"
@@ -201,7 +202,7 @@ func TestSignData(t *testing.T) {
 	if signature != nil {
 		t.Errorf("Expected nil-data, got %x", signature)
 	}
-	if err != keystore.ErrDecrypt {
+	if !errors.Is(err, keystore.ErrDecrypt) {
 		t.Errorf("Expected ErrLocked! '%v'", err)
 	}
 	control.approveCh <- "No way"
@@ -209,7 +210,7 @@ func TestSignData(t *testing.T) {
 	if signature != nil {
 		t.Errorf("Expected nil-data, got %x", signature)
 	}
-	if err != core.ErrRequestDenied {
+	if !errors.Is(err, core.ErrRequestDenied) {
 		t.Errorf("Expected ErrRequestDenied! '%v'", err)
 	}
 	// text/plain

trie/iterator.go

@@ -268,7 +268,7 @@ func (it *nodeIterator) NodeBlob() []byte {
 }
 
 func (it *nodeIterator) Error() error {
-	if it.err == errIteratorEnd {
+	if errors.Is(it.err, errIteratorEnd) {
 		return nil
 	}
 	if seek, ok := it.err.(seekError); ok {
@@ -282,7 +282,7 @@ func (it *nodeIterator) Error() error {
 // sets the Error field to the encountered failure. If `descend` is false,
 // skips iterating over any subnodes of the current node.
 func (it *nodeIterator) Next(descend bool) bool {
-	if it.err == errIteratorEnd {
+	if errors.Is(it.err, errIteratorEnd) {
 		return false
 	}
 	if seek, ok := it.err.(seekError); ok {
@@ -307,7 +307,7 @@ func (it *nodeIterator) seek(prefix []byte) error {
 	// Move forward until we're just before the closest match to key.
 	for {
 		state, parentIndex, path, err := it.peekSeek(key)
-		if err == errIteratorEnd {
+		if errors.Is(err, errIteratorEnd) {
 			return errIteratorEnd
 		} else if err != nil {
 			return seekError{prefix, err}