Pass go tool vet --shadow

ddl/ddl.go

@@ -540,13 +540,17 @@ func (d *ddl) buildIndex(ctx context.Context, t table.Table, idxInfo *model.Inde
 		cols := t.Cols()
 		var vals []interface{}
 		for _, v := range idxInfo.Columns {
+			var (
+				data []byte
+				val  interface{}
+			)
 			col := cols[v.Offset]
 			k := t.RecordKey(h, col)
-			data, err := txn.Get([]byte(k))
+			data, err = txn.Get([]byte(k))
 			if err != nil {
 				return errors.Trace(err)
 			}
-			val, err := t.DecodeValue(data, col)
+			val, err = t.DecodeValue(data, col)
 			if err != nil {
 				return errors.Trace(err)
 			}

driver.go

@@ -353,9 +353,9 @@ func newdriverRows(rs rset.Recordset) *driverRows {
 	go func() {
 		err := io.EOF
 		if e := r.rs.Do(func(data []interface{}) (bool, error) {
-			vv, err := types.Clone(data)
-			if err != nil {
-				return false, errors.Trace(err)
+			vv, cloneErr := types.Clone(data)
+			if cloneErr != nil {
+				return false, errors.Trace(cloneErr)
 			}
 			select {
 			case r.rows <- vv:

plan/plans/distinct.go

@@ -59,9 +59,10 @@ func (r *DistinctDefaultPlan) Do(ctx context.Context, f plan.RowIterFunc) (err e
 
 	var rows [][]interface{}
 	if err = r.Src.Do(ctx, func(id interface{}, in []interface{}) (bool, error) {
+		var v []interface{}
 		// get distinct key
 		key := in[0:r.HiddenFieldOffset]
-		v, err := t.Get(key)
+		v, err = t.Get(key)
 		if err != nil {
 			return false, err
 		}

plan/plans/from.go

@@ -69,14 +69,15 @@ func (r *TableNilPlan) Do(ctx context.Context, f plan.RowIterFunc) error {
 	}
 	defer it.Close()
 	for it.Valid() && strings.HasPrefix(it.Key(), prefix) {
-		var err error
-		id, err := util.DecodeHandleFromRowKey(it.Key())
+		var id int64
+		id, err = util.DecodeHandleFromRowKey(it.Key())
 		if err != nil {
 			return err
 		}
 
 		// do nothing
-		if m, err := f(id, nil); !m || err != nil {
+		var m bool
+		if m, err = f(id, nil); !m || err != nil {
 			return err
 		}
 
@@ -291,7 +292,8 @@ func (r *TableDefaultPlan) Do(ctx context.Context, f plan.RowIterFunc) error {
 		}
 		rks.appendKeys(rke)
 		rec = append(rec, rks)
-		if m, err := f(int64(0), rec); !m || err != nil {
+		m, err := f(int64(0), rec)
+		if !m || err != nil {
 			return err
 		}
 

plan/plans/groupby.go

@@ -152,7 +152,8 @@ func (r *GroupByDefaultPlan) Do(ctx context.Context, f plan.RowIterFunc) (err er
 
 	if len(outRows) == 0 {
 		// empty table
-		out, err := r.evalEmptyTable(ctx)
+		var out []interface{}
+		out, err = r.evalEmptyTable(ctx)
 		if err != nil || out == nil {
 			return err
 		}

plan/plans/union.go

@@ -68,7 +68,6 @@ func (p *UnionPlan) Do(ctx context.Context, f plan.RowIterFunc) error {
 
 	// Eval the following select statements
 	for i, distinct := range p.Distincts {
-		var err error
 		src = p.Srcs[i+1]
 		// Eval src
 		if len(src.GetFields()) != len(rfs) {
@@ -100,9 +99,9 @@ func (p *UnionPlan) Do(ctx context.Context, f plan.RowIterFunc) error {
 			}
 			if distinct {
 				// distinct union, check duplicate
-				v, err := t.Get(in)
-				if err != nil {
-					return false, err
+				v, getErr := t.Get(in)
+				if getErr != nil {
+					return false, getErr
 				}
 				if len(v) > 0 {
 					// Find duplicate, ignore it

stmt/stmts/insert.go

@@ -252,9 +252,9 @@ func (s *InsertIntoStmt) Exec(ctx context.Context) (_ rset.Recordset, err error)
 			// For "insert into t values (default)" Default Eval.
 			m[expressions.ExprEvalDefaultName] = cols[i].Name.O
 
-			val, err := expr.Eval(ctx, m)
-			if err != nil {
-				return nil, errors.Trace(err)
+			val, evalErr := expr.Eval(ctx, m)
+			if evalErr != nil {
+				return nil, errors.Trace(evalErr)
 			}
 			r[cols[i].Offset] = val
 			marked[cols[i].Offset] = struct{}{}

stmt/stmts/union.go

@@ -55,8 +55,6 @@ func (s *UnionStmt) SetText(text string) {
 
 // Plan implements the plan.Planner interface.
 func (s *UnionStmt) Plan(ctx context.Context) (plan.Plan, error) {
-	var r plan.Plan
-	var err error
 	srcs := make([]plan.Plan, 0, len(s.Selects))
 	for _, s := range s.Selects {
 		p, err := s.Plan(ctx)
@@ -65,13 +63,12 @@ func (s *UnionStmt) Plan(ctx context.Context) (plan.Plan, error) {
 		}
 		srcs = append(srcs, p)
 	}
-	if r, err = (&rsets.UnionRset{
+
+	r, err := (&rsets.UnionRset{
 		Srcs:      srcs,
 		Distincts: s.Distincts,
-	}).Plan(ctx); err != nil {
-		return nil, err
-	}
-	return r, nil
+	}).Plan(ctx)
+	return r, err
 }
 
 // Exec implements the stmt.Statement Exec interface.

table/tables/tables.go

@@ -552,7 +552,8 @@ func (t *Table) IterRecords(ctx context.Context, startKey string, cols []*column
 		if err != nil {
 			return err
 		}
-		if more, err := fn(h, data, cols); !more || err != nil {
+		more, err := fn(h, data, cols)
+		if !more || err != nil {
 			return err
 		}