[gcc r13-309] [Ada] Fix spurious ambiguity for if_expression containing operator

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

https://gcc.gnu.org/g:c63b798f88aa82de32789b6a2ae5f387e58165c7

commit r13-309-gc63b798f88aa82de32789b6a2ae5f387e58165c7
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Wed Feb 2 21:04:18 2022 +0100

    [Ada] Fix spurious ambiguity for if_expression containing operator
    
    It comes from a discrepancy in the analysis of binary operators, between
    the predefined ones for which we register an interpretation with the base
    type and the user-defined ones for which we register an interpretation
    with the subtype directly.
    
    This is harmless in almost all cases because the two interpretations do not
    differ by this type property only, but is problematic when the operation is
    the dependent expression of a conditional expression, because it causes two
    interpretations of the conditional expression to be registered, which this
    time differ by this type property only, thus making them impossible to be
    disambiguated later.
    
    gcc/ada/
    
            * sem_ch4.adb (Analyze_User_Defined_Binary_Op): Use the base type
            in the interpretation of the operator.

Diff:
---
 gcc/ada/sem_ch4.adb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/ada/sem_ch4.adb b/gcc/ada/sem_ch4.adb
index c913e8b69d5..ca8e1cd1f24 100644
--- a/gcc/ada/sem_ch4.adb
+++ b/gcc/ada/sem_ch4.adb
@@ -5934,7 +5934,7 @@ package body Sem_Ch4 is
            and then (Has_Compatible_Type (Right_Opnd (N), Etype (F2))
                       or else Etype (F2) = Any_Type)
          then
-            Add_One_Interp (N, Op_Id, Etype (Op_Id));
+            Add_One_Interp (N, Op_Id, Base_Type (Etype (Op_Id)));
 
             --  If the operands are overloaded, indicate that the current
             --  type is a viable candidate. This is redundant in most cases,