NLL Liveness: Skip regionless types when visiting free regions
The tuple-stress benchmark exercises the liveness constraint generation code for types which do not have regions
Closes#52027
ARM: expose the "mclass" target feature
This let us differentiate, in conditional compilation context, between ARM Cortex-M targets, like
the `thumbv*` targets, and other ARM targets, like the ARM Cortex-A Linux targets.
r? @alexcrichton
cc @gnzlbg
cc rust-lang-nursery/stdsimd#437
Deprecate `std::env::home_dir` and fix incorrect documentation
Compare `std::env::home_dir`s claim:
> Returns the value of the 'HOME' environment variable if it is set and not equal to the empty string.
... with its actual behavior:
```
std::env::set_var("HOME", "");
println!("{:?}", std::env::var_os("HOME")); // Some("")
println!("{:?}", std::env::home_dir()); // Some("")
```
The implementation is incorrect in two cases:
- `$HOME` is set, but empty.
- An entry for the user exists in `/etc/passwd`, but it's `pw_dir` is empty.
In both cases Rust considers an empty string to be a valid home directory. This contradicts the documentation, and is wrong in general.
refactor and cleanup region errors for NLL
This is a WIP commit. It simplifies some of the code from https://github.com/rust-lang/rust/pull/51536 and extends a few more steps towards the errors that @davidtwco and I were shooting for. These are intended as a replacement for the general "unable to infer lifetime" messages -- one that is actually actionable. We're certainly not there yet, but the overall shape hopefully gets a bit clearer.
I'm thinking about trying to open up an internals thread to sketch out the overall plan and perhaps discuss how to get the wording right, which special cases to handle, etc.
r? @estebank
cc @davidtwco
Haiku: several smaller fixes to build and run rust on Haiku
This PR combines three small patches that help Rust build and run on the Haiku platform. These patches do not intend to impact other platforms.
enable Atomic*.{load,store} for ARMv6-M / MSP430
closes#45085
as proposed in https://github.com/rust-lang/rust/issues/45085#issuecomment-384825434
this commit adds an `atomic_cas` target option and extends the `#[cfg(target_has_atomic)]`
attribute to enable a subset of the `Atomic*` API on architectures that don't support atomic CAS
natively, like MSP430 and ARMv6-M.
r? @alexcrichton
