[Ada] Fix use type clause partially invalidated by use clause in nested package

[Eric Botcazou]

This is an old issue, whereby a use type clause is partially invalidated by a 
use clause in a nested package, a variant of PR ada/64869 recently fixed too.
The problem occurs only for unusual primitive operators because of a small 
oversight in the implementation.  The fix simply aligns this implementation 
with the one exercised by PR ada/64869, which is more robust.

Tested on x86-64/Linux, applied on the mainline.


2025-10-20  Eric Botcazou  <ebotca...@adacore.com>

        PR ada/52319
        * sem_ch7.adb (Uninstall_Declarations): Use direct test on Nkind
        to spot operators.
        * sem_ch8.adb (End_Use_Package): Also test the Etype of operators
        to spot those which are primitive operators of use-visible types.


2025-10-20  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/use_type3.adb: New test.

-- 
Eric Botcazou
diff --git a/gcc/ada/sem_ch7.adb b/gcc/ada/sem_ch7.adb
index 90219ac8216..2002cc7621f 100644
--- a/gcc/ada/sem_ch7.adb
+++ b/gcc/ada/sem_ch7.adb
@@ -3168,8 +3168,7 @@ package body Sem_Ch7 is
          --  the instantiation of the formals appears in the visible part,
          --  but the formals are private and remain so.
 
-         if Ekind (Id) = E_Function
-           and then Is_Operator_Symbol_Name (Chars (Id))
+         if Nkind (Id) = N_Defining_Operator_Symbol
            and then not Is_Hidden (Id)
            and then not Error_Posted (Id)
          then
diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb
index 4814c0301ed..86344b59c7e 100644
--- a/gcc/ada/sem_ch8.adb
+++ b/gcc/ada/sem_ch8.adb
@@ -5335,23 +5335,19 @@ package body Sem_Ch8 is
       Id        : Entity_Id;
       Elmt      : Elmt_Id;
 
-      function Is_Primitive_Operator_In_Use
-        (Op : Entity_Id;
-         F  : Entity_Id) return Boolean;
-      --  Check whether Op is a primitive operator of a use-visible type
-
-      ----------------------------------
-      -- Is_Primitive_Operator_In_Use --
-      ----------------------------------
-
-      function Is_Primitive_Operator_In_Use
-        (Op : Entity_Id;
-         F  : Entity_Id) return Boolean
-      is
-         T : constant Entity_Id := Base_Type (Etype (F));
+      function Type_In_Use (T : Entity_Id; P : Entity_Id) return Boolean;
+      --  Check whether type T is declared in P and appears in an active
+      --  use_type clause.
+
+      -----------------
+      -- Type_In_Use --
+      -----------------
+
+      function Type_In_Use (T : Entity_Id; P : Entity_Id) return Boolean is
+         BT : constant Entity_Id := Base_Type (T);
       begin
-         return In_Use (T) and then Scope (T) = Scope (Op);
-      end Is_Primitive_Operator_In_Use;
+         return Scope (BT) = P and then (In_Use (T) or else In_Use (BT));
+      end Type_In_Use;
 
    --  Start of processing for End_Use_Package
 
@@ -5381,12 +5377,13 @@ package body Sem_Ch8 is
 
                if Nkind (Id) = N_Defining_Operator_Symbol
                  and then
-                   (Is_Primitive_Operator_In_Use (Id, First_Formal (Id))
+                   (Type_In_Use (Etype (Id), Pack)
+                     or else Type_In_Use (Etype (First_Formal (Id)), Pack)
                      or else
                        (Present (Next_Formal (First_Formal (Id)))
                          and then
-                           Is_Primitive_Operator_In_Use
-                             (Id, Next_Formal (First_Formal (Id)))))
+                           Type_In_Use
+                             (Etype (Next_Formal (First_Formal (Id))), Pack)))
                then
                   null;
                else

-- { dg-do compile }

procedure Use_Type3 is

  package P1 is            
    type T is new Integer;                      
    function "and" (L, R : in Integer) return T;
  end P1;

  package body P1 is                               
    function "and" (L, R : in Integer) return T is
    begin       
      return T (L * R);
    end "and";
  end P1;

  use type P1.T;

  package P2 is
    use P1;
  end P2;

  G : P1.T := Integer'(1) and Integer'(2);

begin
  null;
end;