expression: remove the usage of "TypeClass" in "builtin_op.go" (pingc…

…ap#4547)

expression/builtin_op.go

@@ -339,13 +339,11 @@ func (c *isTrueOrFalseFunctionClass) getFunction(ctx context.Context, args []Exp
 		return nil, errors.Trace(err)
 	}
 
-	argTp := tpInt
-	switch args[0].GetTypeClass() {
-	case types.ClassReal:
-		argTp = tpReal
-	case types.ClassDecimal:
-		argTp = tpDecimal
+	argTp := fieldTp2EvalTp(args[0].GetType())
+	if argTp != tpReal && argTp != tpDecimal {
+		argTp = tpInt
 	}
+
 	bf := newBaseBuiltinFuncWithTp(args, ctx, tpInt, argTp)
 	bf.tp.Flen = 1
 
@@ -549,19 +547,16 @@ func (c *unaryMinusFunctionClass) handleIntOverflow(arg *Constant) (overflow boo
 // typeInfer infers unaryMinus function return type. when the arg is an int constant and overflow,
 // typerInfer will infers the return type as tpDecimal, not tpInt.
 func (c *unaryMinusFunctionClass) typeInfer(argExpr Expression, ctx context.Context) (evalTp, bool) {
-	tp := tpInt
-	switch argExpr.GetTypeClass() {
-	case types.ClassString, types.ClassReal:
+	tp := fieldTp2EvalTp(argExpr.GetType())
+	if tp != tpInt && tp != tpDecimal {
 		tp = tpReal
-	case types.ClassDecimal:
-		tp = tpDecimal
 	}
 
 	sc := ctx.GetSessionVars().StmtCtx
 	overflow := false
 	// TODO: Handle float overflow.
 	if arg, ok := argExpr.(*Constant); sc.InSelectStmt && ok &&
-		arg.GetTypeClass() == types.ClassInt {
+		tp == tpInt {
 		overflow = c.handleIntOverflow(arg)
 		if overflow {
 			tp = tpDecimal
@@ -579,8 +574,8 @@ func (c *unaryMinusFunctionClass) getFunction(ctx context.Context, args []Expres
 	retTp, intOverflow := c.typeInfer(argExpr, ctx)
 
 	var bf baseBuiltinFunc
-	switch argExpr.GetTypeClass() {
-	case types.ClassInt:
+	switch fieldTp2EvalTp(argExprTp) {
+	case tpInt:
 		if intOverflow {
 			bf = newBaseBuiltinFuncWithTp(args, ctx, retTp, tpDecimal)
 			sig = &builtinUnaryMinusDecimalSig{baseDecimalBuiltinFunc{bf}, true}
@@ -591,16 +586,16 @@ func (c *unaryMinusFunctionClass) getFunction(ctx context.Context, args []Expres
 			sig.setPbCode(tipb.ScalarFuncSig_UnaryMinusInt)
 		}
 		bf.tp.Decimal = 0
-	case types.ClassDecimal:
+	case tpDecimal:
 		bf = newBaseBuiltinFuncWithTp(args, ctx, retTp, tpDecimal)
 		bf.tp.Decimal = argExprTp.Decimal
 		sig = &builtinUnaryMinusDecimalSig{baseDecimalBuiltinFunc{bf}, false}
 		sig.setPbCode(tipb.ScalarFuncSig_UnaryMinusDecimal)
-	case types.ClassReal:
+	case tpReal:
 		bf = newBaseBuiltinFuncWithTp(args, ctx, retTp, tpReal)
 		sig = &builtinUnaryMinusRealSig{baseRealBuiltinFunc{bf}}
 		sig.setPbCode(tipb.ScalarFuncSig_UnaryMinusReal)
-	case types.ClassString:
+	default:
 		tp := argExpr.GetType().Tp
 		if types.IsTypeTime(tp) || tp == mysql.TypeDuration {
 			bf = newBaseBuiltinFuncWithTp(args, ctx, retTp, tpDecimal)
@@ -678,24 +673,11 @@ func (c *isNullFunctionClass) getFunction(ctx context.Context, args []Expression
 	if err := c.verifyArgs(args); err != nil {
 		return nil, errors.Trace(err)
 	}
-	tc := args[0].GetType().ToClass()
-	var argTp evalTp
-	switch tc {
-	case types.ClassInt:
-		argTp = tpInt
-	case types.ClassDecimal:
-		argTp = tpDecimal
-	case types.ClassReal:
-		argTp = tpReal
-	default:
-		tp := args[0].GetType().Tp
-		if types.IsTypeTime(tp) {
-			argTp = tpDatetime
-		} else if tp == mysql.TypeDuration {
-			argTp = tpDuration
-		} else {
-			argTp = tpString
-		}
+	argTp := fieldTp2EvalTp(args[0].GetType())
+	if argTp == tpTimestamp {
+		argTp = tpDatetime
+	} else if argTp == tpJSON {
+		argTp = tpString
 	}
 	bf := newBaseBuiltinFuncWithTp(args, ctx, tpInt, argTp)
 	bf.tp.Flen = 1