Range checks in Ada are basically assignment guards with some cute arithmetic attached. Ada still does most of the useful checking at runtime, so you're really just introducing more "index out of bounds". Consumer this example:

procedure Sum_Demo is subtype Index is Integer range 0 .. 10; subtype Small is Integer range 0 .. 10;

   Arr : array(Index) of Integer := (others => 0);
   X : Small := 0;
   I : Integer := Integer'Value(Integer'Image(X));  -- runtime evaluation

begin for J in 1 .. 11 loop I := I + 1; end loop;

   Arr(I) := 42;  -- possible out-of-bounds access if I = 11

end Sum_Demo;

This compile, and the compiler will tell you: "warning: Constraint_Error will be raised at run time".

It's a stupid example for sure. Here's a more complex one:

    procedure Sum_Demo is
       subtype Index is Integer range 0 .. 10;
       subtype Small is Integer range 0 .. 10;
 
       Arr : array(Index) of Integer := (others => 0);
       X : Small := 0;
       I : Integer := Integer'Value(Integer'Image(X));  -- runtime evaluation
    begin
       for J in 1 .. 11 loop
          I := I + 1;
       end loop;
 
       Arr(I) := 42;  -- Let's crash it
    end Sum_Demo;

This again compiles, but if you run it: raised CONSTRAINT_ERROR : sum_demo.adb:13 index check failed

It's a cute feature, but it's useless for anything complex.