In the comments of (closed, defunct) pull request #54884, Mazdak
"Centril" Farrokhzad noted that must-use annotations didn't work on an
associated function (what other communities might call a "static
method"). Subsequent logging revealed that in this case we have a
`Def::Method`, whereas the lint pass was only matching on
`Def::Fn`. (One could argue that those def-names are thereby
misleading—must-use for self-ful methods have always worked—but
documenting or reworking that can be left to another day.)
This commit introduces language items for `Arc` and `Rc` so that types
can later be checked to be `Arc` or `Rc` in the NLL borrow checker. The
`lang` attribute is currently limited to `stage1` as it requires a
compiler built with knowledge of the expected language items.
Update to a new pinning API.
~~Blocked on #53843 because of method resolution problems with new pin type.~~
@r? @cramertj
cc @RalfJung @pythonesque anyone interested in #49150
Add some more wording to module documentation regarding how
`Arc::clone()` works, as some users have assumed cloning Arc's
to work via dereferencing to inner value as follows:
use std::sync::Arc;
let myarc = Arc::new(1);
let myarcref = myarc.clone();
assert!(1 == myarcref);
Instead of the actual mechanic of referencing the existing
Arc value:
use std::sync::Arg;
let myarc = Arc::new(1);
let myarcref = myarc.clone();
assert!(myarcref == &myarc); // not sure if assert could assert this
in the real world
Previously, `is_unique` would not synchronize at all with a `drop` that returned
early because it was not the last reference, leading to a data race.
Fixes#51780
