[gcc r15-9394] Ada: Natural/Positive not ignored in subprogram renaming

[Eric Botcazou via Gcc-cvs]

https://gcc.gnu.org/g:ecef0d7c53d59a701bc09e2df8fbec5d4c61267a

commit r15-9394-gecef0d7c53d59a701bc09e2df8fbec5d4c61267a
Author: Eric Botcazou <ebotca...@adacore.com>
Date:   Sat Apr 12 11:35:44 2025 +0200

    Ada: Natural/Positive not ignored in subprogram renaming
    
    The language says that the profile of a subprogram renaming-as-declaration
    must be mode conformant with that of the renamed subprogram, and that the
    parameter subtypes are taken from the renamed subprogram.
    
    GNAT implements the rule, except when Natural and Positive are involved,
    which may lead to the wrong conclusion that it does not.
    
    gcc/ada/
            PR ada/119643
            * sem_ch8.adb (Inherit_Renamed_Profile): Add guard against the
            peculiarities of Natural and Positive.
    
    gcc/testsuite/
            * gnat.dg/renaming17.adb: New test.

Diff:
---
 gcc/ada/sem_ch8.adb                  |  3 ++-
 gcc/testsuite/gnat.dg/renaming17.adb | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index d4ab44fee923..0a9ef419db78 100644
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -9314,11 +9314,12 @@ package body Sem_Ch8 is
 
             --  If the new type is a renaming of the old one, as is the case
             --  for actuals in instances, retain its name, to simplify later
-            --  disambiguation.
+            --  disambiguation. Beware of Natural and Positive, see Cstand.
 
             if Nkind (Parent (New_T)) = N_Subtype_Declaration
               and then Is_Entity_Name (Subtype_Indication (Parent (New_T)))
               and then Entity (Subtype_Indication (Parent (New_T))) = Old_T
+              and then Scope (New_T) /= Standard_Standard
             then
                null;
             else
diff --git a/gcc/testsuite/gnat.dg/renaming17.adb 
b/gcc/testsuite/gnat.dg/renaming17.adb
new file mode 100644
index 000000000000..d82643318b9f
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/renaming17.adb
@@ -0,0 +1,17 @@
+-- { dg-do run }
+
+procedure Renaming17 is
+
+  function Incr (V : Integer; I : Integer := 1) return Integer is
+    (V + I);
+
+  function Incr_Ren (V : Integer; I : Positive := 1) return Positive
+    renames Incr;
+
+  I : Integer;
+
+begin
+  I := Incr_Ren (-3);
+  I := Incr_Ren (-3, 2);
+  I := Incr_Ren (-3, 0);
+end;