Well godbolt doesn't think so.. 1) this example has an aliasing, no compiler error. https://godbolt.org/z/hzWfj37ef

2) The output value depends of the size of IntArray!

>> with Ada.Text_IO; use Ada.Text_IO; with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;

procedure Text is type IntArray is array (1 .. 500) of Integer;

   type MyStruct is record
      Value : Integer;
       A : IntArray := (others => 0);
   end record;

   function Compute (Value1 : MyStruct; Value2 : in out MyStruct) return Integer is
   begin
      Put_Line ("1 value1=" & Integer'Image(Value1.Value) & " value2=" & Integer'Image(Value2.Value));
      Value2.Value := Value2.Value - 1;
      Put_Line ("2 value1=" & Integer'Image(Value1.Value) & " value2=" & Integer'Image(Value2.Value));
      return Value1.Value * 2;
   end Compute;

   Value1 : MyStruct := (Value => 10, A => (others => 0));
   Value2 : MyStruct := (Value => 20, A => (others => 0));
   Result1 : Integer;
   Result2 : Integer;

begin Result1 := Compute(Value1, Value2); Put_Line ("a value1=" & Integer'Image(Value1.Value) & " value2=" & Integer'Image(Value2.Value) & " result1=" & Integer'Image(Result1)); Result2 := Compute(Value1, Value1); Put_Line ("b value1=" & Integer'Image(Value1.Value) & " value2=" & Integer'Image(Value2.Value) & " result2=" & Integer'Image(Result2)); end Text; <<