On Thu, 05 Nov 2009 19:11:34 -0500, Walter Bright
<[email protected]> wrote:
Steven Schveighoffer wrote:
On Thu, 05 Nov 2009 17:49:33 -0500, Walter Bright
<[email protected]> wrote:
Jason House wrote:
I posted in the other thread how casting to immutable/shared can be
just as bad. A leaked reference prior to casting to immutable/shared
is in effect the same as casting away shared. No matter how you mix
thread local and shared, or mutable and immutable, you still have the
same undefined behavior
Not undefined, it's just that the compiler can't prove it's defined
behavior. Hence, such code would go into a trusted function.
But how does such a trusted function guarantee that the
invariant/shared reference has no other aliases?
It doesn't. Trusted code is verified by the programmer, not the compiler.
OK, you totally ignored my point though. How do you write such a function?
That is, I have a mutable reference x, I want to make it immutable. How
do you write a function to do that?
i.e.:
@safe void foo()
{
x = new X();
x.modifyState(5);
immutable(X) ix = ???; // how to write this part
}
-Steve
