encoding/json: make use of reflect.Type.{OverflowInt, OverflowUint}

CL 567296 adds {OverflowComplex, OverflowFloat, OverflowInt, OverflowUint}
to reflect.Type, this CL uses these methods to simplify code.

Author: callthingsoff

src/encoding/json/decode.go

@@ -776,7 +776,7 @@ func (d *decodeState) object(v reflect.Value) error {
 				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 					s := string(key)
 					n, err := strconv.ParseInt(s, 10, 64)
-					if err != nil || reflect.Zero(kt).OverflowInt(n) {
+					if err != nil || kt.OverflowInt(n) {
 						d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
 						break
 					}
@@ -785,7 +785,7 @@ func (d *decodeState) object(v reflect.Value) error {
 				case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 					s := string(key)
 					n, err := strconv.ParseUint(s, 10, 64)
-					if err != nil || reflect.Zero(kt).OverflowUint(n) {
+					if err != nil || kt.OverflowUint(n) {
 						d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
 						break
 					}