On Thursday, 25 September 2014 at 12:46:01 UTC, Steven
Schveighoffer wrote:
On 9/25/14 5:47 AM, monarch_dodra wrote:
I was playing around with how T.init works. And I think I may
have found
a type loophole.
Given that you may initialize a pointer member to the address
to a
static global:
//----
__gshared int a = 0;
struct S
{
int* p = &a;
}
//----
Then, in theory, any variable, be they mutable or const, are
initialized
to T.init:
//----
void main()
{
immutable S s;
}
//----
This is an issue, because I now have an immutable pointer that
points to
mutable data:
//----
immutable S s = S.init;
immutable int* p = s.p;
assert(*p == 0); //OK
a = 5;
assert(*p == 5); //OK
//----
So this violates the type system...
The question here is:
Is this "legit" code? At what point do you think my code
should have
been rejected?
It should be rejected. The declaration of s (the variable)
should be the trigger, since it casts the pointer to immutable.
Please file a bug report.
-Steve
Hum... So that means certain types just *can't* be initialized
(as immutable) at all?
