> or it could be a different crate FWIW, it can't. Rust enforces that either the trait or the type being impld come from the current crate (with generics it gets more complicated).
I kinda feel like upgrading HeapSizeOf to have a generic second trait-bound argument that we substitute MallocSizeOfOps as would be good. -Manish Goregaokar On Thu, Oct 5, 2017 at 9:05 PM, Nicholas Nethercote <n.netherc...@gmail.com> wrote: > On Fri, Oct 6, 2017 at 2:33 PM, Xidorn Quan <m...@upsuper.org> wrote: > > > > > There are multiple Servo dependencies on crates.io depend on heapsize. > > [1] How are they handled at the moment? And what would we do to them in > > the future with the second option? > > > > [1] https://crates.io/crates/heapsize/reverse_dependencies > > > > Good question. > > There are two ways for the HeapSizeOf trait to be implemented for a type > Foo. > > (1) Foo's crate depends on heapsize, in which case Foo's crate can > implement HeapSizeOf itself. The crates at that link above (app_units, > euclid, url) are examples. The advantage of this option is that the > HeapSizeOf trait can access non-public fields of types. > > (2) Foo's crate doesn't depend on heapsize, in which case a different crate > must implement HeapSizeOf for Foo. This could be the heapsize crate itself > -- as is done for all the standard types like Vec and HashMap -- or it > could be a different crate. The advantage of this option is that you don't > depend on heapsize. > > If we went with the second option from my original mail (i.e. stop using > heapsize) then it would probably make sense to deprecate heapsize entirely, > stop those crates from depending on it, and implement the MallocSizeOf > trait for those crates' types within Servo. > > Nick > > > > Nick > _______________________________________________ > dev-servo mailing list > dev-servo@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-servo > _______________________________________________ dev-servo mailing list dev-servo@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-servo
