3 files changed, 22 insertions, 3 deletions
diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go
index f26a7d49f0..613641afbb 100644
--- a/src/encoding/json/decode.go
+++ b/src/encoding/json/decode.go
@@ -739,7 +739,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		default:
 			d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
 		case reflect.Slice:
-			if v.Type() != byteSliceType {
+			if v.Type().Elem().Kind() != reflect.Uint8 {
 				d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
 				break
 			}
diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
index 7ecc8f4402..f208ee8a7c 100644
--- a/src/encoding/json/decode_test.go
+++ b/src/encoding/json/decode_test.go
@@ -1207,7 +1207,28 @@ func TestStringKind(t *testing.T) {
 	if !reflect.DeepEqual(m1, m2) {
 		t.Error("Items should be equal after encoding and then decoding")
 	}
+}
+
+// Custom types with []byte as underlying type could not be marshalled
+// and then unmarshalled.
+// Issue 8962.
+func TestByteKind(t *testing.T) {
+	type byteKind []byte
+
+	a := byteKind("hello")
 
+	data, err := Marshal(a)
+	if err != nil {
+		t.Error(err)
+	}
+	var b byteKind
+	err = Unmarshal(data, &b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(a, b) {
+		t.Errorf("expected %v == %v", a, b)
+	}
 }
 
 var decodeTypeErrorTests = []struct {
diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
index 4db9f35e69..7789bb5141 100644
--- a/src/encoding/json/encode.go
+++ b/src/encoding/json/encode.go
@@ -275,8 +275,6 @@ func (e *encodeState) error(err error) {
 	panic(err)
 }
 
-var byteSliceType = reflect.TypeOf([]byte(nil))
-
 func isEmptyValue(v reflect.Value) bool {
 	switch v.Kind() {
 	case reflect.Array, reflect.Map, reflect.Slice, reflect.String: