*: use slices.Concat where appropriate

Signed-off-by: Roman Khimov <roman@nspcc.ru>

cli/nep_test/nep17_test.go

@@ -4,6 +4,7 @@ import (
 	"io"
 	"math/big"
 	"path/filepath"
+	"slices"
 	"strconv"
 	"strings"
 	"testing"
@@ -133,8 +134,7 @@ func TestNEP17Transfer(t *testing.T) {
 	}
 
 	t.Run("missing receiver", func(t *testing.T) {
-		as := append([]string{}, args[:8]...)
-		as = append(as, args[10:]...)
+		as := slices.Concat(args[:8], args[10:])
 		e.In.WriteString("one\r")
 		e.RunWithErrorCheck(t, `Required flag "to" not set`, as...)
 		e.In.Reset()

pkg/core/interop/storage/find.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"slices"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
@@ -61,7 +62,7 @@ func (s *Iterator) Value() stackitem.Item {
 	}
 	key := s.curr.Key
 	if s.opts&FindRemovePrefix == 0 {
-		key = append(bytes.Clone(s.prefix), key...)
+		key = slices.Concat(s.prefix, key)
 	}
 	if s.opts&FindKeysOnly != 0 {
 		return stackitem.NewByteArray(key)

pkg/core/mpt/helpers.go

@@ -1,6 +1,10 @@
 package mpt
 
-import "github.com/nspcc-dev/neo-go/pkg/util"
+import (
+	"slices"
+
+	"github.com/nspcc-dev/neo-go/pkg/util"
+)
 
 // lcp returns the longest common prefix of a and b.
 // Note: it does no allocations.
@@ -85,9 +89,7 @@ func GetChildrenPaths(path []byte, node Node) map[util.Uint256][][]byte {
 		}
 	case *ExtensionNode:
 		if n.next.Type() == HashT {
-			cPath := make([]byte, len(path)+len(n.key))
-			copy(cPath, path)
-			copy(cPath[len(path):], n.key)
+			cPath := slices.Concat(path, n.key)
 			res[n.next.Hash()] = [][]byte{cPath}
 		}
 	default:

pkg/core/mpt/trie.go

@@ -5,6 +5,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"slices"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/io"
@@ -616,7 +617,7 @@ func (t *Trie) Find(prefix, from []byte, maxNum int) ([]storage.KeyValue, error)
 		if leaf, ok := node.(*LeafNode); ok {
 			if from == nil || !bytes.Equal(pathToNode, from) { // (*Billet).traverse includes `from` path into result if so. Need to filter out manually.
 				res = append(res, storage.KeyValue{
-					Key:   append(bytes.Clone(prefix), pathToNode...),
+					Key:   slices.Concat(prefix, pathToNode),
 					Value: bytes.Clone(leaf.value),
 				})
 				count++

pkg/core/mpt/trie_store.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"slices"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -98,7 +99,7 @@ func (m *TrieStore) Seek(rng storage.SeekRange, f func(k, v []byte) bool) {
 		if leaf, ok := node.(*LeafNode); ok {
 			// (*Billet).traverse includes `from` path into the result if so. It's OK for Seek, so shouldn't be filtered out.
 			kv := storage.KeyValue{
-				Key:   append(bytes.Clone(rng.Prefix), pathToNode...), // Do not cut prefix.
+				Key:   slices.Concat(rng.Prefix, pathToNode), // Do not cut prefix.
 				Value: bytes.Clone(leaf.value),
 			}
 			return !f(kv.Key, kv.Value) // Should return whether to stop.

pkg/core/storage/store.go

@@ -3,6 +3,7 @@ package storage
 import (
 	"errors"
 	"fmt"
+	"slices"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dbconfig"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dboper"
@@ -105,10 +106,8 @@ type (
 func seekRangeToPrefixes(sr SeekRange) *util.Range {
 	var (
 		rang  *util.Range
-		start = make([]byte, len(sr.Prefix)+len(sr.Start))
+		start = slices.Concat(sr.Prefix, sr.Start)
 	)
-	copy(start, sr.Prefix)
-	copy(start[len(sr.Prefix):], sr.Start)
 
 	if !sr.Backwards {
 		rang = util.BytesPrefix(sr.Prefix)