diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index f1930632fed..313a5efa165 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,11 @@
+2019-08-19  Ed Schonberg  <schonberg@adacore.com>
+
+	* sem_ch6.adb (Check_Synchronized_Overriding): Complete
+	predicate that applies legality check in 9.4 (11.9/2): if an
+	inherited subprogram is implemented by a protected procedure or
+	entry, its first paarameter must be out, in_out or
+	access_to_varible.
+
 2019-08-19  Javier Miranda  <miranda@adacore.com>
 
 	PR ada/65696
diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
index e176535dec6..fb50ec79989 100644
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -7034,6 +7034,11 @@ package body Sem_Ch6 is
       In_Scope    : Boolean;
       Typ         : Entity_Id;
 
+      function Is_Valid_Formal (F : Entity_Id) return Boolean;
+      --  Predicate for legality rule in 9.4 (11.9/2): If an inherited
+      --  subprogram is implemented by a protected procedure or entry,
+      --  its first parameter must be out, in out, or access-to-variable.
+
       function Matches_Prefixed_View_Profile
         (Prim_Params  : List_Id;
          Iface_Params : List_Id) return Boolean;
@@ -7042,6 +7047,19 @@ package body Sem_Ch6 is
       --  Iface_Params. Also determine if the type of first parameter of
       --  Iface_Params is an implemented interface.
 
+      ----------------------
+      --  Is_Valid_Formal --
+      ----------------------
+
+      function Is_Valid_Formal (F : Entity_Id) return Boolean is
+      begin
+         return
+           Ekind_In (F, E_In_Out_Parameter, E_Out_Parameter)
+             or else
+               (Nkind (Parameter_Type (Parent (F))) = N_Access_Definition
+                 and then not Constant_Present (Parameter_Type (Parent (F))));
+      end Is_Valid_Formal;
+
       -----------------------------------
       -- Matches_Prefixed_View_Profile --
       -----------------------------------
@@ -7295,10 +7313,7 @@ package body Sem_Ch6 is
 
                   if Ekind_In (Candidate, E_Entry, E_Procedure)
                     and then Is_Protected_Type (Typ)
-                    and then Ekind (Formal) /= E_In_Out_Parameter
-                    and then Ekind (Formal) /= E_Out_Parameter
-                    and then Nkind (Parameter_Type (Parent (Formal))) /=
-                                                       N_Access_Definition
+                    and then not Is_Valid_Formal (Formal)
                   then
                      null;