diff --git a/LICENSES/LICENSE b/LICENSE
similarity index 100%
rename from LICENSES/LICENSE
rename to LICENSE
diff --git a/ast/ast.go b/ast/ast.go
index 98388fa08b705..8c01f9bb5f07e 100644
--- a/ast/ast.go
+++ b/ast/ast.go
@@ -55,7 +55,7 @@ const (
 // ExprNode is a node that can be evaluated.
 // Name of implementations should have 'Expr' suffix.
 type ExprNode interface {
-	// Node is embeded in ExprNode.
+	// Node is embedded in ExprNode.
 	Node
 	// SetType sets evaluation type to the expression.
 	SetType(tp *types.FieldType)
diff --git a/ddl/index_test.go b/ddl/index_test.go
index 72485bfb6bc9d..22d4a6da5b939 100644
--- a/ddl/index_test.go
+++ b/ddl/index_test.go
@@ -155,7 +155,7 @@ func (s *testIndexSuite) TestIndex(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(exist, IsFalse)
 
-	h, err = t.AddRecord(ctx, types.MakeDatums(1, 1, 1))
+	_, err = t.AddRecord(ctx, types.MakeDatums(1, 1, 1))
 	c.Assert(err, IsNil)
 }
 
diff --git a/infoschema/infoschema.go b/infoschema/infoschema.go
index 069ef3e863387..b657c10332499 100644
--- a/infoschema/infoschema.go
+++ b/infoschema/infoschema.go
@@ -76,7 +76,7 @@ type InfoSchema interface {
 	SchemaMetaVersion() int64
 }
 
-// Infomation Schema Name.
+// Information Schema Name.
 const (
 	Name = "INFORMATION_SCHEMA"
 )
diff --git a/optimizer/plan/plan_test.go b/optimizer/plan/plan_test.go
index 699f31eece104..82a63226f09b3 100644
--- a/optimizer/plan/plan_test.go
+++ b/optimizer/plan/plan_test.go
@@ -346,6 +346,7 @@ func (s *testPlanSuite) TestBestPlan(c *C) {
 		c.Assert(err, IsNil)
 
 		err = Refine(p)
+		c.Assert(err, IsNil)
 		c.Assert(ToString(p), Equals, ca.best, Commentf("for %s cost %v", ca.sql, EstimateCost(p)))
 	}
 }
diff --git a/perfschema/statement_test.go b/perfschema/statement_test.go
index b4f729e03dd3d..75d095ea76152 100644
--- a/perfschema/statement_test.go
+++ b/perfschema/statement_test.go
@@ -29,7 +29,7 @@ func (p *testStatementSuit) TestUninitPS(c *C) {
 	// Run init()
 	ps := &perfSchema{}
 	// ps is uninitialized, all mTables are missing.
-	// This cound happend at the bootstrap stage.
+	// This may happen at the bootstrap stage.
 	// So we must make sure the following actions are safe.
 	err := ps.updateEventsStmtsCurrent(0, []types.Datum{})
 	c.Assert(err, IsNil)
diff --git a/store/localstore/mvcc_test.go b/store/localstore/mvcc_test.go
index 19fe018e57b6d..b782b6bab8f92 100644
--- a/store/localstore/mvcc_test.go
+++ b/store/localstore/mvcc_test.go
@@ -132,7 +132,7 @@ func (t *testMvccSuite) TestMvccPutAndDel(c *C) {
 	})
 	txn, _ = t.s.Begin()
 	txn.Set(encodeInt(0), []byte("v"))
-	v, err = txn.Get(encodeInt(0))
+	_, err = txn.Get(encodeInt(0))
 	c.Assert(err, IsNil)
 	txn.Commit()
 
@@ -191,7 +191,7 @@ func (t *testMvccSuite) TestSnapshotGet(c *C) {
 	// Get version not exists
 	minVerSnapshot, err := t.s.GetSnapshot(kv.MinVersion)
 	c.Assert(err, IsNil)
-	b, err = minVerSnapshot.Get(testKey)
+	_, err = minVerSnapshot.Get(testKey)
 	c.Assert(err, NotNil)
 }
 
diff --git a/table/tables/bounded_tables_test.go b/table/tables/bounded_tables_test.go
index 8dc59e7febd40..ac98d7d58b3a9 100644
--- a/table/tables/bounded_tables_test.go
+++ b/table/tables/bounded_tables_test.go
@@ -115,6 +115,6 @@ func (ts *testBoundedTableSuite) TestBoundedBasic(c *C) {
 	c.Assert(vals[0].GetString(), Equals, "abc")
 
 	c.Assert(tb.Truncate(ctx), IsNil)
-	row, err = tb.Row(ctx, rid)
+	_, err = tb.Row(ctx, rid)
 	c.Assert(err, NotNil)
 }
diff --git a/table/tables/memory_tables_test.go b/table/tables/memory_tables_test.go
index 7831389f1be00..61ff7f24af27b 100644
--- a/table/tables/memory_tables_test.go
+++ b/table/tables/memory_tables_test.go
@@ -116,6 +116,6 @@ func (ts *testMemoryTableSuite) TestMemoryBasic(c *C) {
 	_, err = tb.AddRecord(ctx, types.MakeDatums(1, "abc"))
 	c.Assert(err, IsNil)
 	c.Assert(tb.Truncate(ctx), IsNil)
-	row, err = tb.Row(ctx, rid)
+	_, err = tb.Row(ctx, rid)
 	c.Assert(err, NotNil)
 }
diff --git a/util/hack/hack_test.go b/util/hack/hack_test.go
index 8a3a2a9301b05..9490ede5fff03 100644
--- a/util/hack/hack_test.go
+++ b/util/hack/hack_test.go
@@ -34,7 +34,7 @@ func TestString(t *testing.T) {
 
 	b = append(b, "abc"...)
 	if a != "aello world" {
-		t.Fatal(a)
+		t.Fatalf("a:%v, b:%v", a, b)
 	}
 }