diff --git a/cmd/gc/main.go b/cmd/gc/main.go
index d0532e3f0d..4d1ba3a141 100644
--- a/cmd/gc/main.go
+++ b/cmd/gc/main.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/XinFinOrg/XDPoSChain/cmd/utils"
 	"github.com/XinFinOrg/XDPoSChain/common"
+	"github.com/XinFinOrg/XDPoSChain/common/lru"
 	"github.com/XinFinOrg/XDPoSChain/core"
 	"github.com/XinFinOrg/XDPoSChain/core/rawdb"
 	"github.com/XinFinOrg/XDPoSChain/core/state"
@@ -20,7 +21,6 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/ethdb/leveldb"
 	"github.com/XinFinOrg/XDPoSChain/rlp"
 	"github.com/XinFinOrg/XDPoSChain/trie"
-	"github.com/XinFinOrg/XDPoSChain/common/lru"
 )
 
 var (
@@ -170,7 +170,7 @@ func getAllChilds(n StateNode, db *leveldb.Database) ([17]*StateNode, error) {
 				}
 				if err == nil {
 					childs[i] = &StateNode{node: childNode, path: append(n.path, byte(i))}
-				} else if err != nil {
+				} else {
 					_, ok := err.(*trie.MissingNodeError)
 					if !ok {
 						return childs, err
@@ -187,7 +187,7 @@ func getAllChilds(n StateNode, db *leveldb.Database) ([17]*StateNode, error) {
 		}
 		if err == nil {
 			childs[0] = &StateNode{node: childNode, path: append(n.path, node.Key...)}
-		} else if err != nil {
+		} else {
 			_, ok := err.(*trie.MissingNodeError)
 			if !ok {
 				return childs, err
diff --git a/core/blockchain.go b/core/blockchain.go
index 8d9dbf573d..48a7e69b5e 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -1659,7 +1659,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, []
 					}
 				}
 				//check
-				if tradingState != nil && tradingService != nil {
+				if tradingState != nil {
 					gotRoot := tradingState.IntermediateRoot()
 					expectRoot, _ := tradingService.GetTradingStateRoot(block, author)
 					parentRoot, _ := tradingService.GetTradingStateRoot(parent, parentAuthor)
@@ -1938,7 +1938,7 @@ func (bc *BlockChain) getResultBlock(block *types.Block, verifiedM2 bool) (*Resu
 					}
 				}
 			}
-			if tradingState != nil && tradingService != nil {
+			if tradingState != nil {
 				gotRoot := tradingState.IntermediateRoot()
 				expectRoot, _ := tradingService.GetTradingStateRoot(block, author)
 				parentRoot, _ := tradingService.GetTradingStateRoot(parent, parentAuthor)
diff --git a/eth/handler.go b/eth/handler.go
index 913d7f07b3..5cdb4876a8 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -285,9 +285,7 @@ func (pm *ProtocolManager) removePeer(id string) {
 		log.Debug("Peer removal failed", "peer", id, "err", err)
 	}
 	// Hard disconnect at the networking layer
-	if peer != nil {
-		peer.Peer.Disconnect(p2p.DiscUselessPeer)
-	}
+	peer.Peer.Disconnect(p2p.DiscUselessPeer)
 }
 
 func (pm *ProtocolManager) Start(maxPeers int) {