[Bug ada/17953] New: Illegal program not detected, RM 3.9.2(9)

[ludovic dot brenta at insalien dot org]

Debian Bug #276224:

--  If the expected type for an expression or name is some specific
--  tagged type, then the expression or name shall not be dynamically
--  tagged unless it is a controlling operand in a call on a
--  dispatching operation.
procedure Test_121 is
   package pak1 is
      type T1 is tagged null record;
      function f1 (x1: T1) return T1;
   end pak1;

   package body pak1 is
      function f1 (x1: T1) return T1 is
      begin
         return x1;
      end;
   end pak1;
   use pak1;

   type T2 is record
      a1: T1;
   end record;

   z0: T1'class := T1'(null record);
   z1: T1 := f1(z0);           -- ERROR: gnat correctly rejects
   z2: T2 := (a1 => f1(z0));   -- ERROR: gnat mistakenly allows
begin
   null;
end Test_121;


The output is:

test_121.adb:24:14: dynamically tagged expression not allowed
gnatmake: "test_121.adb" compilation error


The second error is not detected.

-- 
           Summary: Illegal program not detected, RM 3.9.2(9)
           Product: gcc
           Version: 3.4.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ada
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ludovic dot brenta at insalien dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17953