Prefix to 'ACCESS must either statically match... But why?

[wojtek@power.com.pl (Wojtek Narczynski)]

Hello,

Could somebody please explain me why is this rule present? I find it
very limting. Is this because AR2 bounds are not stored with the
object?

Type Stream_Element_Array_access is access all Stream_Element_Array;

AR1 : aliased Stream_Element_Array := ( 2, 4, 5 );
AR2 : aliased Stream_Element_Array ( 1 .. 3 ) := ( 2, 4, 5 );

AR1A : Stream_Element_Array_access := AR1'access;

-- Illegal
AR2A : Stream_Element_Array_access := AR2'access;


LRM:3.10.2(27), The nominal subtype of the prefix to 'ACCESS or
'UNCHECKED_ACCESS must either statically match the designated subtype
of the expected type or the designated subtype must be discriminated
and unconstrained, Continuing


Thanks,
Wojtek