On 2009-12-16 14:02:35 -0500, "Steven Schveighoffer"
<schvei...@yahoo.com> said:
On Wed, 16 Dec 2009 09:21:16 -0500, Michel Fortin
<michel.for...@michelf.com> wrote:
Here's what I meant:
void doSomething(inout(MyStruct)*[] a, inout(MyStruct)*[] b) {
a[0] = b[0]; // works only when structs in both arrays have the same
constness.
}
This is dangerous.
We should figure out a reason why this shouldn't compile. It's hard
for me to wrap my head around it. Either the implicit cast when
calling the function shouldn't work, or the assignment shouldn't work.
My intuition is that the implicit cast should fail.
If you're trying to define a ruke it's simple: you can cast immutable
to const only on the first level of indirection, or when there is no
indirection. So basically those conversions should be allowed:
immutable(MyStruct)*[] -> const(MyStruct*)[]
immutable(MyStruct*)[] -> const(MyStruct*)[]
immutable(MyStruct*[]) -> const(MyStruct*[])
So the above function can only be called wi
Does this code compile today? If so, we need to fix this. With this
fixed, the inout version naturally becomes invalid.
Just did a couple of small tests. Apparently everything is all right:
test.d(18): Error: cannot implicitly convert expression (a) of type
immutable(int)*[] to const(int)*[]
Also:
test.d(18): Error: cannot implicitly convert expression (b) of type
int*[] to const(int)*[]
Which is right otherwise you could assign immutable values to the array
others see as mutable. Also, converting from immutable(int)*[] to
const(int*)[] implicitly works fine and does prevent dangerous
assignments.
So I don't think there is anything to fix on this front.
--
Michel Fortin
michel.for...@michelf.com
http://michelf.com/
