The existence of these two functions is at odds with our current [error
conventions][conventions] which recommend that panicking and `Result`-like
variants should not be provided together.
[conventions]: https://github.com/rust-lang/rfcs/blob/master/text/0236-error-conventions.md#do-not-provide-both-result-and-fail-variants
This commit adds a new `borrow_state` function returning a `BorrowState` enum to
`RefCell` which serves as a replacemnt for the `try_borrow` and `try_borrow_mut`
functions.
Functions are needed for safety and convenience.
It is a common pattern to use `mem::transmute` to convert between
`Box` and raw pointer, like this:
```
let b = Box::new(3);
let p = mem::transmute(b);
// pass `p` to some C library
```
After this commit, conversion can be written as:
```
let p = b.into_raw();
```
`into_raw` and `from_raw` functions are still unsafe, but they are
much safer than `mem::transmute`, because *raw functions do not
convert between incompatible pointers. For example, this likely
incorrect code can be successfully compiled:
```
let p: *mut u64 = ...
let b: Box<u32> = mem::transmute(p);
```
Using `from_raw` results in compile-time error:
```
let p: *mut u64 = ...
let b: Box<u32> = Box::from_raw(p); // compile-time error
```
`into_raw` and `from_raw` functions are similar to C++ `std::unique_ptr`
`release` function [1] and constructor from pointer [2].
[1] http://en.cppreference.com/w/cpp/memory/unique_ptr/release
[2] http://en.cppreference.com/w/cpp/memory/unique_ptr/unique_ptr
Now that associated types are fully implemented the iterator adaptors only need
type parameters which are associated with actual storage. All other type
parameters can either be derived from these (e.g. they are an associated type)
or can be bare on the `impl` block itself.
This is a breaking change due to the removal of type parameters on these
iterator adaptors, but code can fairly easily migrate by just deleting the
relevant type parameters for each adaptor. Other behavior should not be
affected.
Closes#21839
[breaking-change]
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]
The new `::ops::Range` has separated implementations for each of the
numeric types, while the old `::iter::Range` has one for type `Int`.
However, we do not take output bindings into account when selecting
traits. So it confuses `typeck` and makes the new range does not work as
good as the old one when it comes to type inference.
This patch implements `Iterator` for the new range for one type `Int`.
This limitation could be lifted, however, if we ever reconsider the
output types' role in type inference.
Closes#21595Closes#21649Closes#21672
Functions are needed for safety and convenience.
It is a common pattern to use `mem::transmute` to convert between
`Box` and raw pointer, like this:
```
let b = Box::new(3);
let p = mem::transmute(b);
// pass `p` to some C library
```
After this commit, conversion can be written as:
```
let p = boxed::into_raw(b);
```
`into_raw` and `from_raw` functions are still unsafe, but they are
much safer than `mem::transmute`, because *raw functions do not
convert between incompatible pointers. For example, this likely
incorrect code can be successfully compiled:
```
let p: *mut u64 = ...
let b: Box<u32> = mem::transmute(p);
```
Using `from_raw` results in compile-time error:
```
let p: *mut u64 = ...
let b: Box<u32> = Box::from_raw(p); // compile-time error
```
`into_raw` and `from_raw` functions are similar to C++ `std::unique_ptr`
`release` function [1] and constructor from pointer [2].
[1] http://en.cppreference.com/w/cpp/memory/unique_ptr/release
[2] http://en.cppreference.com/w/cpp/memory/unique_ptr/unique_ptr
- the specific block for dl* function isn't need for openbsd if libdl
isn't marked to be linked here. remove them.
- remove the linkage for libdl: it should already specified in `rtdeps.rs`.
the code of `dynamic_lib.rs` include libdl for:
- linux (already defined in rtdeps.rs)
- android (already defined in rtdeps.rs)
- macos (not needed for macos)
- ios (probably the same as macos)
- freebsd (libdl is a stub)
- dragonfly (libdl is a stub)
This code is in a block (libc::consts::os) that openbsd don't include
This one is for freebsd and dragonfly. There is another block for openbsd below.
Remove the unneed declaration.
- consolidate target_record_sp_limit and target_get_sp_limit functions
for aarch64, powerpc, arm-ios and openbsd as there are all without
segmented stacks (no need to duplicate functions).
- rename __load_self function to rust_load_self
- use a mutex inner load_self() as underline implementation is not thread-safe
Currently, we only infer the kind of a closure based on the expected type or explicit annotation. If neither applies, we currently report an error. This pull request changes that case to defer the decision until we are able to analyze the actions of the closure: closures which mutate their environment require `FnMut`, closures which move out of their environment require `FnOnce`.
This PR is not the end of the story:
- It does not remove the explicit annotations nor disregard them. The latter is the logical next step to removing them (we'll need a snapshot before we can do anything anyhow). Disregarding explicit annotations might expose more bugs since right now all closures in libstd/rustc use explicit annotations or the expected type, so this inference never kicks in.
- The interaction with instantiating type parameter fallbacks leaves something to be desired. This is mostly just saying that the algorithm from https://github.com/rust-lang/rfcs/pull/213 needs to be implemented, which is a separate bug. There are some semi-subtle interactions though because not knowing whether a closure is `Fn` vs `FnMut` prevents us from resolving obligations like `F : FnMut(...)`, which can in turn prevent unification of some type parameters, which might (in turn) lead to undesired fallback. We can improve this situation however -- even if we don't know whether (or just how) `F : FnMut(..)` holds or not for some closure type `F`, we can still perform unification since we *do* know the argument and return types. Once kind inference is done, we can complete the `F : FnMut(..)` analysis -- which might yield an error if (e.g.) the `F` moves out of its environment.
r? @nick29581
specialized to closures, and invoke them as soon as we know the
closure kind. I thought initially we would need a fixed-point
inference algorithm but it appears I was mistaken, so we can do this.
upvar inference. Upvar inference can cause some obligations to be
deferred, notably things like `F : Sized` where `F` is a closure type,
or `F : FnMut`. Adjust the ordering therefore so that we process all
traits and apply fallback, do upvar inference, and only then start
reporting errors for outstanding obligations.
doing the final checking for closure calls until after trait inference
is performed. This isn't important now, but it's essential if we are to
delay inferring the closure kind.
Removes `Copy` from `ops::Range` (`a..b`) and `ops::RangeFrom` (`a..`)
[breaking-change]
---
I forgot about these two in #20790, this PR also adds `Clone` to the `Peekable` adapter which used to be `Copy`able.
r? @nikomatsakis or anyone
The new `::ops::Range` has separated implementations for each of the
numeric types, while the old `::iter::Range` has one for type `Int`.
However, we do not take output bindings into account when selecting
traits. So it confuses `typeck` and makes the new range does not work as
good as the old one when it comes to type inference.
This patch implements `Iterator` for the new range for one type `Int`.
This limitation could be lifted, however, if we ever reconsider the
output types' role in type inference.
Closes#21595Closes#21649Closes#21672
Unicode escapes were changed in [this
RFC](28aeb3c391/text/0446-es6-unicode-escapes.md)
to use the ES6 \u{00FFFF} syntax with a variable number of digits from
1-6, eliminating the need for two different syntaxes for unicode
literals.
Update the coherence rules to "covered first" -- the first type parameter to contain either a local type or a type parameter must contain only covered type parameters.
cc #19470.
Fixes#20974.
Fixes#20749.
r? @aturon
