[gcc r14-6691] ada: Cope with Sem_Util.Enclosing_Declaration oddness.

[Marc Poulhi?s]

https://gcc.gnu.org/g:5c374c0907b4da06c163e3d15f182d91f1114ff2

commit r14-6691-g5c374c0907b4da06c163e3d15f182d91f1114ff2
Author: Steve Baird <baird@adacore.com>
Date:   Tue Nov 21 11:00:37 2023 -0800

    ada: Cope with Sem_Util.Enclosing_Declaration oddness.
    
    Sem_Util.Enclosing_Declaration can return a non-empty result which is not
    a declaration; clients may need to compensate for the case where an
    N_Subprogram_Specification node is returned. One such client is the function
    Is_Actual_Subp_Of_Inst.
    
    gcc/ada/
    
            * sem_ch8.adb (Is_Actual_Subp_Of_Inst): After calling
            Enclosing_Declaration, add a check for the case where one more
            Parent call is needed to get the enclosing declaration.

Diff:
---
 gcc/ada/sem_ch8.adb | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index c5bf0864671..2e6b1b6d785 100644
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -2691,7 +2691,7 @@ package body Sem_Ch8 is
                --  Each attempt to find a suitable primitive of a particular
                --  type operates on its own copy of the original renaming.
                --  As a result the original renaming is kept decoration and
-               --  side-effect-free.
+               --  side-effect free.
 
                --  Inherit the overloaded status of the renamed subprogram name
 
@@ -6550,6 +6550,16 @@ package body Sem_Ch8 is
 
                      Decl := Enclosing_Declaration (E);
 
+                     --  Enclosing_Declaration does not always return a
+                     --  declaration; cope with this irregularity.
+                     if Decl in N_Subprogram_Specification_Id
+                       and then Nkind (Parent (Decl)) in
+                         N_Subprogram_Body | N_Subprogram_Declaration
+                           | N_Subprogram_Renaming_Declaration
+                     then
+                        Decl := Parent (Decl);
+                     end if;
+
                      --  Look for the suprogram renaming declaration built
                      --  for a generic actual subprogram. Unclear why
                      --  Original_Node call is needed, but sometimes it is.