patch 9.0.2156: Vim9: can use typealias in assignment

Problem:  Vim9: can use typealias in an assignment
Solution: Generate errors when class/typealias involved in the rhs of an
          assignment

closes: #13637

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
Generate errors when class/typealias involved in assignment.
diff --git a/src/evalvars.c b/src/evalvars.c
index fd3c937..343f636 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -1836,11 +1836,8 @@
 	return NULL;
     }
 
-    if (tv->v_type == VAR_TYPEALIAS)
-    {
-	semsg(_(e_using_typealias_as_value), tv->vval.v_typealias->ta_name);
+    if (check_typval_is_value(tv) == FAIL)
 	return NULL;
-    }
 
     if (*arg == '$')
     {