patch 8.2.3264: Vim9: assign test fails

Problem:    Vim9: assign test fails.
Solution:   Add missing change.
diff --git a/src/eval.c b/src/eval.c
index 769816d..3688176 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1515,9 +1515,11 @@
     char_u	*s;
     int		failed = FALSE;
 
-    // Can't do anything with a Funcref, Dict, v:true on the right.
+    // Can't do anything with a Funcref or Dict on the right.
+    // v:true and friends only work with "..=".
     if (tv2->v_type != VAR_FUNC && tv2->v_type != VAR_DICT
-		      && tv2->v_type != VAR_BOOL && tv2->v_type != VAR_SPECIAL)
+		    && ((tv2->v_type != VAR_BOOL && tv2->v_type != VAR_SPECIAL)
+								|| *op == '.'))
     {
 	switch (tv1->v_type)
 	{