This commit cleans out a large amount of deprecated APIs from the standard
library and some of the facade crates as well, updating all users in the
compiler and in tests as it goes along.
This commit stabilizes the following APIs:
* `TypeId::of` - now that it has an `Any` bound it's ready to be stable.
* `Box<Any>::downcast` - now that an inherent impl on `Box<Any>` as well as
`Box<Any+Send>` is allowed the `BoxAny` trait is removed in favor of these
inherent methods.
This is a breaking change due to the removal of the `BoxAny` trait, but
consumers can simply remove imports to fix crates.
[breaking-change]
This attribute has been deprecated in favor of #[should_panic]. This also
updates rustdoc to no longer accept the `should_fail` directive and instead
renames it to `should_panic`.
This commit provides a safe, but unstable interface for the `try` functionality
of running a closure and determining whether it panicked or not.
There are two primary reasons that this function was previously marked `unsafe`:
1. A vanilla version of this function exposes the problem of exception safety by
allowing a bare try/catch in the language. It is not clear whether this
concern should be directly tied to `unsafe` in Rust at the API level. At this
time, however, the bounds on `ffi::try` require the closure to be both
`'static` and `Send` (mirroring those of `thread::spawn`). It may be possible
to relax the bounds in the future, but for now it's the level of safety that
we're willing to commit to.
2. Panicking while panicking will leak resources by not running destructors.
Because panicking is still controlled by the standard library, safeguards
remain in place to prevent this from happening.
The new API is now called `catch_panic` and is marked as `#[unstable]` for now.
This attribute has been deprecated in favor of #[should_panic]. This also
updates rustdoc to no longer accept the `should_fail` directive and instead
renames it to `should_panic`.
Reject specialized Drop impls.
See Issue #8142 for discussion.
This makes it illegal for a Drop impl to be more specialized than the original item.
So for example, all of the following are now rejected (when they would have been blindly accepted before):
```rust
struct S<A> { ... };
impl Drop for S<i8> { ... } // error: specialized to concrete type
struct T<'a> { ... };
impl Drop for T<'static> { ... } // error: specialized to concrete region
struct U<A> { ... };
impl<A:Clone> Drop for U<A> { ... } // error: added extra type requirement
struct V<'a,'b>;
impl<'a,'b:a> Drop for V<'a,'b> { ... } // error: added extra region requirement
```
Due to examples like the above, this is a [breaking-change].
(The fix is to either remove the specialization from the `Drop` impl, or to transcribe the requirements into the struct/enum definition; examples of both are shown in the PR's fixed to `libstd`.)
----
This is likely to be the last thing blocking the removal of the `#[unsafe_destructor]` attribute.
Fix#8142Fix#23584
This commit provides a safe, but unstable interface for the `try` functionality
of running a closure and determining whether it panicked or not.
There are two primary reasons that this function was previously marked `unsafe`:
1. A vanilla version of this function exposes the problem of exception safety by
allowing a bare try/catch in the language. It is not clear whether this
concern should be directly tied to `unsafe` in Rust at the API level. At this
time, however, the bounds on `ffi::try` require the closure to be both
`'static` and `Send` (mirroring those of `thread::spawn`). It may be possible
to relax the bounds in the future, but for now it's the level of safety that
we're willing to commit to.
2. Panicking while panicking will leak resources by not running destructors.
Because panicking is still controlled by the standard library, safeguards
remain in place to prevent this from happening.
The new API is now called `catch_panic` and is marked as `#[unstable]` for now.
This is a [breaking-change]. When indexing a generic map (hashmap, etc) using the `[]` operator, it is now necessary to borrow explicitly, so change `map[key]` to `map[&key]` (consistent with the `get` routine). However, indexing of string-valued maps with constant strings can now be written `map["abc"]`.
r? @japaric
cc @aturon @Gankro
This commit implements [RFC
909](https://github.com/rust-lang/rfcs/pull/909):
The `std::thread_local` module is now deprecated, and its contents are
available directly in `std::thread` as `LocalKey`, `LocalKeyState`, and
`ScopedKey`.
The macros remain exactly as they were, which means little if any code
should break. Nevertheless, this is technically a:
[breaking-change]
Closes#23547
