A new section is added to both both struct and trait doc pages.
On struct/enum pages, a new 'Auto Trait Implementations' section displays any
synthetic implementations for auto traits. Currently, this is only done
for Send and Sync.
On trait pages, a new 'Auto Implementors' section displays all types
which automatically implement the trait. Effectively, this is a list of
all public types in the standard library.
Synthesized impls for a particular auto trait ('synthetic impls') take
into account generic bounds. For example, a type 'struct Foo<T>(T)' will
have 'impl<T> Send for Foo<T> where T: Send' generated for it.
Manual implementations of auto traits are also taken into account. If we have
the following types:
'struct Foo<T>(T)'
'struct Wrapper<T>(Foo<T>)'
'unsafe impl<T> Send for Wrapper<T>' // pretend that Wrapper<T> makes
this sound somehow
Then Wrapper will have the following impl generated:
'impl<T> Send for Wrapper<T>'
reflecting the fact that 'T: Send' need not hold for 'Wrapper<T>: Send'
to hold
Lifetimes, HRTBS, and projections (e.g. '<T as Iterator>::Item') are
taken into account by synthetic impls
However, if a type can *never* implement a particular auto trait
(e.g. 'struct MyStruct<T>(*const T)'), then a negative impl will be
generated (in this case, 'impl<T> !Send for MyStruct<T>')
All of this means that a user should be able to copy-paste a synthetic
impl into their code, without any observable changes in behavior
(assuming the rest of the program remains unchanged).
RFC 2070 part 1: PanicInfo and Location API changes
This implements part of https://rust-lang.github.io/rfcs/2070-panic-implementation.html
Tracking issue: https://github.com/rust-lang/rust/issues/44489
* Move `std::panic::PanicInfo` and `std::panic::Location` to a new `core::panic` module. The two types and the `std` module were already `#[stable]` and stay that way, the new `core` module is `#[unstable]`.
* Add a new `PanicInfo::message(&self) -> Option<&fmt::Arguments>` method, which is `#[unstable]`.
* Implement `Display` for `PanicInfo` and `Location`
