[Ada] New restriction No_Tagged_Type_Registration

gcc/ada/

	* libgnat/s-rident.ads (No_Tagged_Type_Registration): New
	restriction identifier.
	* restrict.ads (Implementation_Restriction): Add restriction.
	* exp_ch7.adb (Process_Declarations): Suppress
	tagged-type-related finalization actions if the restriction is
	active.  Call RTE_Available last.
	* exp_disp.adb (Make_DT): Likewise.
	* exp_util.adb (Requires_Cleanup_Actions): Return False for a
	tagged type declaration if No_Tagged_Type_Registration is
	active.
	* sem_attr.adb (Check_Stream_Attribute): Check restriction
	No_Tagged_Type_Registration.
	* libgnat/a-except.ads (Null_Occurrence): Minor: Initialize, to
	avoid stopping at a warning in gdb.
	* doc/gnat_rm/standard_and_implementation_defined_restrictions.rst:
	Document new restriction.
	* gnat_rm.texi: Regenerate.

1 files changed, 9 insertions, 0 deletions

diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb
index 2cd8c14..4344885 100644
--- a/gcc/ada/sem_attr.adb
+++ b/gcc/ada/sem_attr.adb
@@ -2622,6 +2622,15 @@ package body Sem_Attr is
             Check_Restriction (No_Exception_Registration, P);
          end if;
 
+         --  If the No_Tagged_Type_Registration restriction is active, then
+         --  class-wide streaming attributes are not allowed.
+
+         if Restriction_Check_Required (No_Tagged_Type_Registration)
+           and then Is_Class_Wide_Type (P_Type)
+         then
+            Check_Restriction (No_Tagged_Type_Registration, P);
+         end if;
+
          --  Here we must check that the first argument is an access type
          --  that is compatible with Ada.Streams.Root_Stream_Type'Class.