library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity ent is
  generic (
    TUSER_WIDTH : natural := 1); -- Changing TUSER_WIDTH to a local constant inside ent fixes the issue
end ent;

architecture ent of ent is

  -- constant TUSER_WIDTH : natural := 1;

  type data_t is record
    tuser : std_logic_vector;
  end record;

  type data_array_t is array (natural range <>) of data_t;
  type std_logic_array_t is array (natural range <>) of std_logic_vector;
  subtype tuser_array_t is std_logic_array_t(open)(TUSER_WIDTH - 1 downto 0);

begin

  process
    ------------------------------------------------------------------------------------
    procedure write_data (
      constant tuser : tuser_array_t                    -- Fails!
      -- constant tuser : std_logic_array_t(open)(open) -- Works
      -- constant tuser : std_logic_array_t             -- Works
     ) is
    begin

      -- All entries will show as zero when it fails!
      for i in tuser'range loop
        report integer'image(i) & " =>" & integer'image(to_integer(unsigned(tuser(i))));
      end loop;

      assert tuser(1)(0) = '1'; -- <<<<<====== This should not fail
    end procedure;

    ------------------------------------------------------------------------------------
    procedure handle_data_array ( constant data : data_array_t) is
      variable local_tuser : std_logic_array_t(data'range)(TUSER_WIDTH - 1 downto 0);
      -- variable local_tuser : tuser_array_t(data'range); -- This fails in this procedure!
    begin
      -- Convert a list of tuples into two lists
      for i in data'range loop
        local_tuser(i) := data(i).tuser;
        -- This assertion fails when local_tuser type is one of
        --  tuser_array_t(data'range)
        --  tuser_array_t(0 to 1)
        -- It will pass if the local_tuser is of type std_logic_array_t(data'range)(TUSER_WIDTH - 1 downto 0);
        assert local_tuser(i) = data(i).tuser
          report "local_tuser and data(i).tuser should not be different here";
      end loop;

      write_data(tuser => local_tuser);
    end;

    ------------------------------------------------------------------------------------
    constant data : data_array_t(0 to 1)(tuser(0 downto 0)) := (0 => (tuser => (0 downto 0 => '0')),
                                                                1 => (tuser => (0 downto 0 => '1')));
  begin
    handle_data_array(data);
    wait;
  end process;
end ent;