[gcc r12-5017] [Ada] Fix support for prefixed call with incomplete type declarations

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:ca803c3d7ba5c6626d37e615aec1748ac4199c9b

commit r12-5017-gca803c3d7ba5c6626d37e615aec1748ac4199c9b
Author: Yannick Moy <moy@adacore.com>
Date:   Mon Oct 25 12:48:22 2021 +0200

    [Ada] Fix support for prefixed call with incomplete type declarations
    
    gcc/ada/
    
            * sem_ch3.adb (Analyze_Incomplete_Type_Decl): Add the missing
            initialization.

Diff:
---
 gcc/ada/sem_ch3.adb | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
index 152ef83387d..ff3da385943 100644
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -3506,6 +3506,15 @@ package body Sem_Ch3 is
          Set_Is_Tagged_Type (T, True);
          Set_No_Tagged_Streams_Pragma (T, No_Tagged_Streams);
          Make_Class_Wide_Type (T);
+      end if;
+
+      --  For tagged types, or when prefixed-call syntax is allowed for
+      --  untagged types, initialize the list of primitive operations to
+      --  an empty list.
+
+      if Tagged_Present (N)
+        or else Extensions_Allowed
+      then
          Set_Direct_Primitive_Operations (T, New_Elmt_List);
       end if;