accounts/abi: fix set function (ethereum#25477)

* accounts/abi: fix set function

* don't break things

* update test

Author: zhiqiangxu

accounts/abi/reflect.go

@@ -99,7 +99,7 @@ func mustArrayToByteSlice(value reflect.Value) reflect.Value {
 func set(dst, src reflect.Value) error {
 	dstType, srcType := dst.Type(), src.Type()
 	switch {
-	case dstType.Kind() == reflect.Interface && dst.Elem().IsValid():
+	case dstType.Kind() == reflect.Interface && dst.Elem().IsValid() && (dst.Elem().Type().Kind() == reflect.Ptr || dst.Elem().CanSet()):
 		return set(dst.Elem(), src)
 	case dstType.Kind() == reflect.Ptr && dstType.Elem() != reflect.TypeOf(big.Int{}):
 		return set(dst.Elem(), src)

accounts/abi/unpack_test.go

@@ -352,6 +352,11 @@ func TestMethodMultiReturn(t *testing.T) {
 		&[]interface{}{&expected.Int, &expected.String},
 		"",
 		"Can unpack into a slice",
+	}, {
+		&[]interface{}{&bigint, ""},
+		&[]interface{}{&expected.Int, expected.String},
+		"",
+		"Can unpack into a slice without indirection",
 	}, {
 		&[2]interface{}{&bigint, new(string)},
 		&[2]interface{}{&expected.Int, &expected.String},