diff --git a/gcc/ada/par-ch12.adb b/gcc/ada/par-ch12.adb
index 56ec4a15f39cc5fb74e7343358040da83a52cfcb..ae6b6cd48d579a1af965b94d688309eddd8af455 100644
--- a/gcc/ada/par-ch12.adb
+++ b/gcc/ada/par-ch12.adb
@@ -153,7 +153,11 @@ package body Ch12 is
 
       Decl_Loop : loop
          P_Pragmas_Opt (Decls);
-         Ignore (Tok_Private);
+
+         if Token = Tok_Private then
+            Error_Msg_S ("generic private child packages not permitted");
+            Scan; -- past PRIVATE
+         end if;
 
          if Token = Tok_Use then
             Append (P_Use_Clause, Decls);