[Ada] Sem_Ch4: minor code cleanup

2018-07-16  Javier Miranda  <miranda@adacore.com>

gcc/ada/

	* sem_ch4.adb (Analyze_Membership_Op): Code cleanup.

From-SVN: r262704

gcc/ada/ChangeLog

 2018-07-16  Javier Miranda  <miranda@adacore.com>
 
+	* sem_ch4.adb (Analyze_Membership_Op): Code cleanup.
+
+2018-07-16  Javier Miranda  <miranda@adacore.com>
+
 	* exp_attr.adb (Expand_N_Attribute_Reference ['Count]): Do not
 	transform 'Count into a function call if the current scope has been
 	eliminated.

gcc/ada/sem_ch4.adb

@@ -3031,15 +3031,9 @@ package body Sem_Ch4 is
       Analyze_Expression (L);
 
       if No (R) then
-         if Ada_Version >= Ada_2012 then
-            Analyze_Set_Membership;
-            Check_Function_Writable_Actuals (N);
-         else
-            Error_Msg_N
-              ("multiple choices in membership tests only allowed in Ada 2012",
-               N);
-         end if;
-
+         pragma Assert (Ada_Version >= Ada_2012);
+         Analyze_Set_Membership;
+         Check_Function_Writable_Actuals (N);
          return;
       end if;