std: Stabilize TypeId and tweak BoxAny #21165

alexcrichton · 2015-01-15T00:16:13Z

This commit aims to stabilize the TypeId abstraction by moving it out of the
intrinsics module into the any module of the standard library. Specifically,

TypeId is now defined at std::any::TypeId
TypeId::hash has been removed in favor of an implementation of Hash.

This commit also performs a final pass over the any module, confirming the
following:

Any::get_type_id remains unstable as usage of the Any trait will likely
never require this, and the Any trait does not need to be implemented for
any other types. As a result, this implementation detail can remain unstable
until associated statics are implemented.
Any::downcast_ref is now stable
Any::downcast_mut is now stable
BoxAny remains unstable. While a direct impl on Box<Any> is allowed today
it does not allow downcasting of trait objects like Box<Any + Send> (those
returned from Thread::join). This is covered by Replace current quasi-subtyping relationship for object types with coercions #18737.
BoxAny::downcast is now stable.

alexcrichton · 2015-01-15T00:16:17Z

r? @aturon

rust-highfive · 2015-01-15T00:16:17Z

r? @aturon

(rust_highfive has picked a reviewer for you, use r? to override)

seanmonstar · 2015-01-15T16:29:51Z

src/libcore/any.rs

+/// printing, and showing.
+///
+/// A `TypeId` is currently only available for types which ascribe to `'static`,
+/// but this limitatoin may be removed in the future.


Typo limitation

aturon · 2015-01-15T18:51:17Z

OK, I'm happy with this, but want to get @nikomatsakis's opinion as well.

nikomatsakis · 2015-01-15T20:22:59Z

src/libcore/any.rs

+    /// instantiated with
+    #[cfg(not(stage0))]
+    #[stable]
+    pub fn of<T: ?Sized + 'static>() -> TypeId {


So obviously the key question is this function, right? I'm roughly willing to go with this, but I'd like to get a better understanding of whether we could get by with some kind of bound here.

nikomatsakis · 2015-01-16T16:21:14Z

On Thu, Jan 15, 2015 at 10:51:22AM -0800, Aaron Turon wrote:

OK, I'm happy with this, but want to get @nikomatsakis's opinion as well.

After discussing with @reem in IRC, it seems like we want to move to a
design where there is a Reflect trait that is automatically
implemented for all types:

trait Reflect : 'static { }
impl Trait for .. { }

TypeId would thus require a Reflect bound

@flaper87 is actually pretty close to having the .. stuff implemented in full, I think,
so this could plausibly land very soon.

In the meantime it might make sense to keep of() as unstable?

alexcrichton · 2015-01-16T18:35:26Z

r? @aturon

I've marked TypeId::of as #[unstable] for now until the marker trait is implemented

aturon · 2015-01-16T18:49:54Z

Sidenote: the (currently stable) blanket impl for Any will likely also grow a reflect bound. This is unlikely to be a breaking change in practice.

reem · 2015-01-16T19:44:19Z

It will actually require a Reflect bound, since it will use TypeId::of.

This commit aims to stabilize the `TypeId` abstraction by moving it out of the `intrinsics` module into the `any` module of the standard library. Specifically, * `TypeId` is now defined at `std::any::TypeId` * `TypeId::hash` has been removed in favor of an implementation of `Hash`. This commit also performs a final pass over the `any` module, confirming the following: * `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely never require this, and the `Any` trait does not need to be implemented for any other types. As a result, this implementation detail can remain unstable until associated statics are implemented. * `Any::downcast_ref` is now stable * `Any::downcast_mut` is now stable * `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today it does not allow downcasting of trait objects like `Box<Any + Send>` (those returned from `Thread::join`). This is covered by #18737. * `BoxAny::downcast` is now stable.

alexcrichton · 2015-01-19T02:23:11Z

@bors: r=aturon 80d73e9

alexcrichton · 2015-01-19T02:23:20Z

@bors: retry

alexcrichton · 2015-01-19T02:28:02Z

@bors r=aturon e1e0450

This commit aims to stabilize the `TypeId` abstraction by moving it out of the `intrinsics` module into the `any` module of the standard library. Specifically, * `TypeId` is now defined at `std::any::TypeId` * `TypeId::hash` has been removed in favor of an implementation of `Hash`. This commit also performs a final pass over the `any` module, confirming the following: * `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely never require this, and the `Any` trait does not need to be implemented for any other types. As a result, this implementation detail can remain unstable until associated statics are implemented. * `Any::downcast_ref` is now stable * `Any::downcast_mut` is now stable * `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today it does not allow downcasting of trait objects like `Box<Any + Send>` (those returned from `Thread::join`). This is covered by rust-lang#18737. * `BoxAny::downcast` is now stable.

alexcrichton · 2015-01-19T20:15:20Z

@bors: r=aturon 70f165

bors · 2015-01-19T20:15:21Z

🙀 You have the wrong number! Please try again with 70f7.

alexcrichton · 2015-01-19T20:15:29Z

@bors: r=aturon 70f7165

bors · 2015-01-19T23:35:12Z

⌛ Testing commit 70f7165 with merge 65b61ff...

This commit aims to stabilize the `TypeId` abstraction by moving it out of the `intrinsics` module into the `any` module of the standard library. Specifically, * `TypeId` is now defined at `std::any::TypeId` * `TypeId::hash` has been removed in favor of an implementation of `Hash`. This commit also performs a final pass over the `any` module, confirming the following: * `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely never require this, and the `Any` trait does not need to be implemented for any other types. As a result, this implementation detail can remain unstable until associated statics are implemented. * `Any::downcast_ref` is now stable * `Any::downcast_mut` is now stable * `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today it does not allow downcasting of trait objects like `Box<Any + Send>` (those returned from `Thread::join`). This is covered by #18737. * `BoxAny::downcast` is now stable.

bors · 2015-01-20T01:34:24Z

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-32-nopt-t, auto-win-32-opt, auto-win-64-nopt-t, auto-win-64-opt

rust-highfive assigned aturon Jan 15, 2015

aturon mentioned this pull request Jan 15, 2015

Stabilization for 1.0-alpha2 #20761

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seanmonstar reviewed Jan 15, 2015
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alexcrichton force-pushed the second-pass-type-id branch from 5a234b8 to d72e978 Compare January 15, 2015 16:44

nikomatsakis reviewed Jan 15, 2015
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alexcrichton force-pushed the second-pass-type-id branch from d72e978 to 80d73e9 Compare January 16, 2015 18:35

alexcrichton force-pushed the second-pass-type-id branch from 80d73e9 to e1e0450 Compare January 19, 2015 02:27

alexcrichton force-pushed the second-pass-type-id branch from e1e0450 to 70f7165 Compare January 19, 2015 02:29

bors merged commit 70f7165 into rust-lang:master Jan 20, 2015

alexcrichton deleted the second-pass-type-id branch January 20, 2015 04:24

bvssvni mentioned this pull request May 26, 2016

What's the purpose of EventId? PistonDevelopers/piston#1070

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std: Stabilize TypeId and tweak BoxAny #21165

std: Stabilize TypeId and tweak BoxAny #21165

alexcrichton commented Jan 15, 2015

alexcrichton commented Jan 15, 2015

rust-highfive commented Jan 15, 2015

seanmonstar Jan 15, 2015

aturon commented Jan 15, 2015

nikomatsakis Jan 15, 2015

nikomatsakis commented Jan 16, 2015

alexcrichton commented Jan 16, 2015

aturon commented Jan 16, 2015

reem commented Jan 16, 2015

alexcrichton commented Jan 19, 2015

alexcrichton commented Jan 19, 2015

alexcrichton commented Jan 19, 2015

alexcrichton commented Jan 19, 2015

bors commented Jan 19, 2015

alexcrichton commented Jan 19, 2015

bors commented Jan 19, 2015

bors commented Jan 20, 2015

std: Stabilize TypeId and tweak BoxAny #21165

std: Stabilize TypeId and tweak BoxAny #21165

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alexcrichton commented Jan 15, 2015

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