The main intent is to fix cases where EndRegion emission is believed
to be causing excess peak memory pressure.
It may also be a welcome change to people inspecting the MIR output
who find the EndRegions to be a distraction.
Compact display of static lib dependencies
Fixes#33173
Instead of displaying one dependency per line, I've changed the format to display them all in one line.
As a bonus they're in format of linker flags (`-lfoo`), so the output can be copy&pasted if one is actually going to link as suggested.
expand on using rustup custom toolchains in CONTRIBUTING.md
fixes#42484
Should i include more notes about how to use a local build *without* rustup? It can kinda feel like a cop-out otherwise. Other means that come to mind are setting `$RUSTC` directly and fully installing it.
cc @rust-lang/docs
Although types that don't implement Drop can't be Copyable, this can
still be useful when ManuallyDrop is used inside a generic type. This
doesn't derive from Copy as that would require T: Copy + Clone, instead
it provides an impl of Clone for T: Clone.
rustc: Flag {i,u}128 as unsafe for FFI
These don't appear to have a stable ABI as noted in #41799 and the work in
compiler-builtins definitely seems to be confirming it!
More general `on_unimplemented`, with uses in `Try`
Allow `on_unimplemented` directives to specify both the label and the primary message of the trait error, and allow them to be controlled by flags - currently only to be desugaring-sensitive.
e.g.
```Rust
#[rustc_on_unimplemented(
on(all(direct, from_desugaring="?"),
message="the `?` operator can only be used in a \
function that returns `Result` \
(or another type that implements `{Try}`)",
label="cannot use the `?` operator in a function that returns `{Self}`"),
)]
```
r? @nikomatsakis
Implement downcast the like it exists for Box.
The implementation avoids using into_raw/from_raw, because the pointer
arithmetic which should cancel does not seem to optimize out at the
moment.
Since Rc<T> is never Send, only Rc<Any> and not Rc<Any + Send>
implements downcast.
