patch 9.0.1128: build failure

Problem:    Build failure.
Solution:   Add type cast.  Add missing error messages.

Author: brammool

src/errors.h

@@ -3401,3 +3401,9 @@ EXTERN char e_member_not_found_on_class_str_str[]
 EXTERN char e_cannot_add_textprop_with_text_after_using_textprop_with_negative_id[]
 	INIT(= N_("E1339: Cannot add a textprop with text after using a textprop with a negative id"));
 #endif
+#ifdef FEAT_EVAL
+EXTERN char e_argument_already_declared_in_class_str[]
+	INIT(= N_("E1340: Argument already declared in the class: %s"));
+EXTERN char e_variable_already_declared_in_class_str[]
+	INIT(= N_("E1341: Variable already declared in the class: %s"));
+#endif

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1128,
 /**/
     1127,
 /**/

src/vim9class.c

@@ -827,7 +827,8 @@ find_class_func(char_u **arg)
     size_t len = name_end - name;
     typval_T tv;
     tv.v_type = VAR_UNKNOWN;
-    if (eval_variable(name, len, 0, &tv, NULL, EVAL_VAR_NOAUTOLOAD) == FAIL)
+    if (eval_variable(name, (int)len,
+				    0, &tv, NULL, EVAL_VAR_NOAUTOLOAD) == FAIL)
 	return NULL;
     if (tv.v_type != VAR_CLASS && tv.v_type != VAR_OBJECT)
 	goto fail_after_eval;