# VHDL127: Only allowed attributes should be used ## Summary ```{raw} html

Reliability	Security	Maintainability	Code attribute	Effort to fix	Tags

LOW	-	-	Intentionality \| Logical	20min	synthesis, vscode, linter

``` ## Description ```{raw} html

Related rules

Forbidden attributes should not be used

Attributes usage is limited to a given set of authorized attributes. This rule raises an issue for any attribute other than:

event
high
left
length
low
range
right

This list can be changed through the allowedAttributes parameter.

Noncompliant code example

architecture rtl of top is
  type state_type is (Init, Hold, Strobe, Read, Idle);
  variable V: state_type := state_type’val(2); -- Noncompliant: "val" is not allowed
begin
end;

Compliant solution

architecture rtl of top is
  type bit_array is array (15 downto 0) of bit;
  variable my_var : integer := bit_array’left(bit_array’range); -- Compliant: "left" is allowed
begin
end;

``` ## Parameters ```{raw} html

Parameter	Value	Description

allowedAttributes	event,high,left,length,low,range,right	Comma-separated list of allowed attributes

``` ```{raw} html ```