[gcc r14-5645] ada: Fix spurious error on call with default parameter in generic package

[gcc r14-5645] ada: Fix spurious error on call with default parameter in generic package

[Marc Poulhi?s]

https://gcc.gnu.org/g:50e0095904e0c66b24c205a7d776e6366bc9c7c0

commit r14-5645-g50e0095904e0c66b24c205a7d776e6366bc9c7c0
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Fri Oct 20 17:22:07 2023 +0200

    ada: Fix spurious error on call with default parameter in generic package
    
    This occurs when the default value is a function call returning a private
    type, and is caused by a bad interaction between two internal mechanisms.
    
    gcc/ada/
    
            * sem_ch12.adb (Save_Global_References.Set_Global_Type): Beef up
            comment about the setting of the full view.
            * sem_res.adb (Resolve_Actuals.Insert_Default): Add another bypass
            for the case of a generic context.

Diff:
---
 gcc/ada/sem_ch12.adb |  7 +++++--
 gcc/ada/sem_res.adb  | 14 +++++++++++---
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb
index f73e1b53b0e..31fcbedf774 100644
--- a/gcc/ada/sem_ch12.adb
+++ b/gcc/ada/sem_ch12.adb
@@ -16938,8 +16938,11 @@ package body Sem_Ch12 is
          elsif No (Full_View (Typ)) and then Typ /= Etype (Typ) then
             null;
 
-         --  Otherwise mark the type for flipping and use the full view when
-         --  available.
+         --  Otherwise mark the type for flipping and set the full view on N2
+         --  when available, which is necessary for Check_Private_View to swap
+         --  back the views in case the full declaration of Typ is visible in
+         --  the instantiation context. Note that this will be problematic if
+         --  N2 is re-analyzed later, e.g. if it's a default value in a call.
 
          else
             Set_Has_Private_View (N);
diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
index 42f7c10c5c5..70a84176054 100644
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -4017,13 +4017,21 @@ package body Sem_Res is
                   Analyze_And_Resolve (Actval, Base_Type (Etype (Actval)));
 
                --  Resolve entities with their own type, which may differ from
-               --  the type of a reference in a generic context (the view
-               --  swapping mechanism did not anticipate the re-analysis of
-               --  default values in calls).
+               --  the type of a reference in a generic context because of the
+               --  trick used in Save_Global_References.Set_Global_Type to set
+               --  full views forcefully, which did not anticipate the need to
+               --  re-analyze default values in calls.
 
                elsif Is_Entity_Name (Actval) then
                   Analyze_And_Resolve (Actval, Etype (Entity (Actval)));
 
+               --  Ditto for calls whose name is an entity, for the same reason
+
+               elsif Nkind (Actval) = N_Function_Call
+                 and then Is_Entity_Name (Name (Actval))
+               then
+                  Analyze_And_Resolve (Actval, Etype (Entity (Name (Actval))));
+
                else
                   Analyze_And_Resolve (Actval, Etype (Actval));
                end if;