Implement step 1 of rust-lang/rfcs#702
Allows the expression `..` (without either endpoint) in general, can be
used in slicing syntax `&expr[..]` where we previously wrote `&expr[]`.
The old syntax &expr[] is not yet removed or warned for.
This is an implementation of [RFC 578][rfc] which adds a new `std::env` module
to replace most of the functionality in the current `std::os` module. More
details can be found in the RFC itself, but as a summary the following methods
have all been deprecated:
[rfc]: https://github.com/rust-lang/rfcs/pull/578
* `os::args_as_bytes` => `env::args`
* `os::args` => `env::args`
* `os::consts` => `env::consts`
* `os::dll_filename` => no replacement, use `env::consts` directly
* `os::page_size` => `env::page_size`
* `os::make_absolute` => use `env::current_dir` + `join` instead
* `os::getcwd` => `env::current_dir`
* `os::change_dir` => `env::set_current_dir`
* `os::homedir` => `env::home_dir`
* `os::tmpdir` => `env::temp_dir`
* `os::join_paths` => `env::join_paths`
* `os::split_paths` => `env::split_paths`
* `os::self_exe_name` => `env::current_exe`
* `os::self_exe_path` => use `env::current_exe` + `pop`
* `os::set_exit_status` => `env::set_exit_status`
* `os::get_exit_status` => `env::get_exit_status`
* `os::env` => `env::vars`
* `os::env_as_bytes` => `env::vars`
* `os::getenv` => `env::var` or `env::var_string`
* `os::getenv_as_bytes` => `env::var`
* `os::setenv` => `env::set_var`
* `os::unsetenv` => `env::remove_var`
Many function signatures have also been tweaked for various purposes, but the
main changes were:
* `Vec`-returning APIs now all return iterators instead
* All APIs are now centered around `OsString` instead of `Vec<u8>` or `String`.
There is currently on convenience API, `env::var_string`, which can be used to
get the value of an environment variable as a unicode `String`.
All old APIs are `#[deprecated]` in-place and will remain for some time to allow
for migrations. The semantics of the APIs have been tweaked slightly with regard
to dealing with invalid unicode (panic instead of replacement).
The new `std::env` module is all contained within the `env` feature, so crates
must add the following to access the new APIs:
#![feature(env)]
[breaking-change]
This commits adds an associated type to the `FromStr` trait representing an
error payload for parses which do not succeed. The previous return value,
`Option<Self>` did not allow for this form of payload. After the associated type
was added, the following attributes were applied:
* `FromStr` is now stable
* `FromStr::Err` is now stable
* `FromStr::from_str` is now stable
* `StrExt::parse` is now stable
* `FromStr for bool` is now stable
* `FromStr for $float` is now stable
* `FromStr for $integral` is now stable
* Errors returned from stable `FromStr` implementations are stable
* Errors implement `Display` and `Error` (both impl blocks being `#[stable]`)
Closes#15138
The regex library was largely used for non-critical aspects of the compiler and
various external tooling. The library at this point is duplicated with its
out-of-tree counterpart and as such imposes a bit of a maintenance overhead as
well as compile time hit for the compiler itself.
The last major user of the regex library is the libtest library, using regexes
for filters when running tests. This removal means that the filtering has gone
back to substring matching rather than using regexes.
Part of #18085
Instead of using an Enum, we use a struct with Option<&Tree> as leaves. It allow
to limit a lot of allocation.
before:
```
texitoi@vaio:~/dev/benchmarksgame-rs$ time ./bin/binary-trees-orig 20
stretch tree of depth 21 check: -1
2097152 trees of depth 4 check: -2097152
524288 trees of depth 6 check: -524288
131072 trees of depth 8 check: -131072
32768 trees of depth 10 check: -32768
8192 trees of depth 12 check: -8192
2048 trees of depth 14 check: -2048
512 trees of depth 16 check: -512
128 trees of depth 18 check: -128
32 trees of depth 20 check: -32
long lived tree of depth 20 check: -1
real 0m3.860s
user 0m11.032s
sys 0m3.572s
```
after:
```
texitoi@vaio:~/dev/benchmarksgame-rs$ time ./bin/binary-trees 20
stretch tree of depth 21 check: -1
2097152 trees of depth 4 check: -2097152
524288 trees of depth 6 check: -524288
131072 trees of depth 8 check: -131072
32768 trees of depth 10 check: -32768
8192 trees of depth 12 check: -8192
2048 trees of depth 14 check: -2048
512 trees of depth 16 check: -512
128 trees of depth 18 check: -128
32 trees of depth 20 check: -32
long lived tree of depth 20 check: -1
real 0m2.824s
user 0m9.224s
sys 0m1.428s
```
This gets rid of the 'experimental' level, removes the non-staged_api
case (i.e. stability levels for out-of-tree crates), and lets the
staged_api attributes use 'unstable' and 'deprecated' lints.
This makes the transition period to the full feature staging design
a bit nicer.
