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/errors.h b/src/errors.h
index c8eaac7..2788800 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3557,10 +3557,16 @@
 	INIT(= N_("E1401: Using type alias \"%s\" as a Float"));
 EXTERN char e_using_typealias_as_string[]
 	INIT(= N_("E1402: Using type alias \"%s\" as a String"));
-EXTERN char e_using_typealias_as_value[]
+EXTERN char e_using_typealias_as_value_str[]
 	INIT(= N_("E1403: Type alias \"%s\" cannot be used as a value"));
 EXTERN char e_abstract_cannot_be_used_in_interface[]
 	INIT(= N_("E1404: Abstract cannot be used in an interface"));
+EXTERN char e_using_class_as_value_str[]
+	INIT(= N_("E1403: Class \"%s\" cannot be used as a value"));
+EXTERN char e_using_class_as_var_val[]
+	INIT(= N_("E1405: Cannot use a Class as a variable or value"));
+EXTERN char e_using_typealias_as_var_val[]
+	INIT(= N_("E1406: Cannot use a Typealias as a variable or value"));
 #endif
 // E1405 - E1499 unused (reserved for Vim9 class support)
 EXTERN char e_cannot_mix_positional_and_non_positional_str[]