[Ada] Improve error message on illegal prefixed procedure call

[Pierre-Marie de Rodat]

This patch improves an error message on an illegal prefixed procedure
call Obj.Name (Args) when Name denotes a visible component of Obj, as
well as a primitive operation of the type of Obj.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * sem_ch6.adb (Analyze_Call_And_Resolve): Add information to the
        error message on an illegal procedure call, when the illegality
        is due to the presence of a component of the full view of the
        target object, as well as a procedure with the same name (See RM
        4.1.3 (9.2/3)).
diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -2420,6 +2420,27 @@ package body Sem_Ch6 is
 
       else
          Error_Msg_N ("invalid procedure or entry call", N);
+
+         --  Specialize the error message in the case where both a
+         --  primitive operation and a record component are visible
+         --  at the same time.
+
+         if Nkind (P) = N_Selected_Component
+           and then Is_Entity_Name (Selector_Name (P))
+         then
+            declare
+               Sel : constant Entity_Id := Entity (Selector_Name (P));
+            begin
+               if Ekind (Sel) = E_Component
+                 and then Present (Homonym (Sel))
+                 and then Ekind (Homonym (Sel)) = E_Procedure
+               then
+                  Error_Msg_NE ("\component & conflicts with"
+                    & " homonym procedure (RM 4.1.3 (9.2/3))",
+                    Selector_Name (P), Sel);
+               end if;
+            end;
+         end if;
       end if;
 
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