Reading a output signal from within a procedure should be illegal even in VHDL 2008 #1212
Description
The following code passes when analysing with the --std=2008 flag, but it should produce an error instead (see ghdl/ghdl#2360):
library ieee;
use ieee.std_logic_1164.all;
package tb_utils is
end package tb_utils;
package body tb_utils is
procedure f_gen_clk(signal clk : out std_logic;
constant freq : in natural) is
begin
loop
wait for (0.5 / real(freq)) * 1 sec;
clk <= not clk;
end loop;
end procedure f_gen_clk;
end package body;$ nvc --std=2008 -a ghdl-nvc-procedure-out.vhd # no error
$ ghdl -a --std=08 ghdl-nvc-procedure-out.vhd
ghdl-nvc-procedure-out.vhd:14:18:error: signal interface "clk" cannot be read
clk <= not clk;
^
ghdl:error: compilation error