Per API meeting
https://github.com/rust-lang/meeting-minutes/blob/master/Meeting-API-review-2014-08-13.md
# Changes to `core::option`
Most of the module is marked as stable or unstable; most of the unstable items are awaiting resolution of conventions issues.
However, a few methods have been deprecated, either due to lack of use or redundancy:
* `take_unwrap`, `get_ref` and `get_mut_ref` (redundant, and we prefer for this functionality to go through an explicit .unwrap)
* `filtered` and `while`
* `mutate` and `mutate_or_set`
* `collect`: this functionality is being moved to a new `FromIterator` impl.
# Changes to `core::result`
Most of the module is marked as stable or unstable; most of the unstable items are awaiting resolution of conventions issues.
* `collect`: this functionality is being moved to a new `FromIterator` impl.
* `fold_` is deprecated due to lack of use
* Several methods found in `core::option` are added here, including `iter`, `as_slice`, and variants.
Due to deprecations, this is a:
[breaking-change]
This changes the internal representation of `Duration` from
days: i32,
secs: i32,
nanos: u32
to
secs: i64,
nanos: i32
This resolves#16466. Note that `nanos` is an `i32` and not `u32` as suggested, because `i32` is easier to deal with, and it is not exposed anyway. Some methods now take `i64` instead of `i32` due to the increased range. Some methods, like `num_milliseconds`, now return an `Option<i64>` instead of `i64`, because the range of `Duration` is now larger than e.g. 2^63 milliseconds.
A few remarks:
- Negating `MIN` is impossible. I chose to return `MAX` as `-MIN`, but it is one nanosecond less than the actual negation. Is this the desired behaviour?
- In `std::io::timer`, some functions accept a `Duration`, which is internally converted into a number of milliseconds. However, the range of `Duration` is now larger than 2^64 milliseconds. There is already a FIXME in the file that this should be addressed (without a ticket number though). I chose to silently use 0 ms if the duration is too long. Is that right, as long as the backend still uses milliseconds?
- Negative durations are not formatted correctly, but they were not formatted correctly before either.
[breaking-change]
1. The internal layout for traits has changed from (vtable, data) to (data, vtable). If you were relying on this in unsafe transmutes, you might get some very weird and apparently unrelated errors. You should not be doing this! Prefer not to do this at all, but if you must, you should use raw::TraitObject rather than hardcoding rustc's internal representation into your code.
2. The minimal type of reference-to-vec-literals (e.g., `&[1, 2, 3]`) is now a fixed size vec (e.g., `&[int, ..3]`) where it used to be an unsized vec (e.g., `&[int]`). If you want the unszied type, you must explicitly give the type (e.g., `let x: &[_] = &[1, 2, 3]`). Note in particular where multiple blocks must have the same type (e.g., if and else clauses, vec elements), the compiler will not coerce to the unsized type without a hint. E.g., `[&[1], &[1, 2]]` used to be a valid expression of type '[&[int]]'. It no longer type checks since the first element now has type `&[int, ..1]` and the second has type &[int, ..2]` which are incompatible.
3. The type of blocks (including functions) must be coercible to the expected type (used to be a subtype). Mostly this makes things more flexible and not less (in particular, in the case of coercing function bodies to the return type). However, in some rare cases, this is less flexible. TBH, I'm not exactly sure of the exact effects. I think the change causes us to resolve inferred type variables slightly earlier which might make us slightly more restrictive. Possibly it only affects blocks with unreachable code. E.g., `if ... { fail!(); "Hello" }` used to type check, it no longer does. The fix is to add a semicolon after the string.
This commits takes a similar strategy to the previous commit to implement
close_accept and clone for the native win32 pipes implementation.
Closes#15595
This commits implements {Tcp,Unix}Acceptor::{clone,close_accept} methods for
unix. A windows implementation is coming in a later commit.
The clone implementation is based on atomic reference counting (as with all
other clones), and the close_accept implementation is based on selecting on a
self-pipe which signals that a close has been seen.
This enables `num_milliseconds` to return an `i64` again instead of
`Option<i64>`, because it is guaranteed not to overflow.
The Duration range is now rougly 300e6 years (positive and negative),
whereas it was 300e9 years previously. To put these numbers in
perspective, 300e9 years is about 21 times the age of the universe
(according to Wolfram|Alpha). 300e6 years is about 1/15 of the age of
the earth (according to Wolfram|Alpha).
Pros:
I like this example because it's concise without being trivial. The Monty Hall example code is somewhat lengthy and possibly inaccessible to those unfamiliar with probability.
Cons:
The Monty Hall example already exists. Do we need another example? Also, this is probably inaccessible to people who don't know basic geometry.
int/uint aren't considered FFI safe, replace them with the actual type they
represent (i64/u64 or i32/u32). This is a breaking change, but at most a cast
to `uint` or `int` needs to be added.
[breaking-change]
As of RFC 18, struct layout is undefined. Opting into a C-compatible struct
layout is now down with #[repr(C)]. For consistency, specifying a packed
layout is now also down with #[repr(packed)]. Both can be specified.
To fix errors caused by this, just add #[repr(C)] to the structs, and change
#[packed] to #[repr(packed)]
Closes#14309
[breaking-change]
This changes the internal representation of `Duration` from
days: i32,
secs: i32,
nanos: u32
to
secs: i64,
nanos: i32
This resolves#16466. Some methods now take `i64` instead of `i32` due
to the increased range. Some methods, like `num_milliseconds`, now
return an `Option<i64>` instead of `i64`, because the range of
`Duration` is now larger than e.g. 2^63 milliseconds.
The first commit improves code generation through a few changes:
- The `#[inline]` attributes allow llvm to constant fold the encoding step away in certain situations. For example, code like this changes from a call to `encode_utf8` in a inner loop to the pushing of a byte constant:
```rust
let mut s = String::new();
for _ in range(0u, 21) {
s.push_char('a');
}
```
- Both methods changed their semantic from causing run time failure if the target buffer is not large enough to returning `None` instead. This makes llvm no longer emit code for causing failure for these methods.
- A few debug `assert!()` calls got removed because they affected code generation due to unwinding, and where basically unnecessary with today's sound handling of `char` as a Unicode scalar value.
~~The second commit is optional. It changes the methods from regular indexing with the `dst[i]` syntax to unsafe indexing with `dst.unsafe_mut_ref(i)`. This does not change code generation directly - in both cases llvm is smart enough to see that there can never be an out-of-bounds access. But it makes it emit a `nounwind` attribute for the function.
However, I'm not sure whether that is a real improvement, so if there is any objection to this I'll remove the commit.~~
This changes how the methods behave on a too small buffer, so this is a
[breaking-change]
declared with the same name in the same scope.
This breaks several common patterns. First are unused imports:
use foo::bar;
use baz::bar;
Change this code to the following:
use baz::bar;
Second, this patch breaks globs that import names that are shadowed by
subsequent imports. For example:
use foo::*; // including `bar`
use baz::bar;
Change this code to remove the glob:
use foo::{boo, quux};
use baz::bar;
Or qualify all uses of `bar`:
use foo::{boo, quux};
use baz;
... baz::bar ...
Finally, this patch breaks code that, at top level, explicitly imports
`std` and doesn't disable the prelude.
extern crate std;
Because the prelude imports `std` implicitly, there is no need to
explicitly import it; just remove such directives.
The old behavior can be opted into via the `import_shadowing` feature
gate. Use of this feature gate is discouraged.
This implements RFC #116.
Closes#16464.
[breaking-change]
- Both can now be inlined and constant folded away
- Both can no longer cause failure
- Both now return an `Option` instead
Removed debug `assert!()`s over the valid ranges of a `char`
- It affected optimizations due to unwinding
- Char handling is now sound enought that they became uneccessary
* Fix `LimitReader`'s `Buffer::consume` impl to avoid limit underflow
* Make `MultiWriter` fail fast instead of always running through each
`Writer`. This may or may not be what we want, but it at least
doesn't throw any errors encountered in later `Writer`s into oblivion.
* Prevent `IterReader`'s `Reader::read` impl from returning EOF if given
an empty buffer.
[breaking-change]
* Fix `LimitReader`'s `Buffer::consume` impl to avoid limit underflow
* Make `MultiWriter` fail fast instead of always running through each
`Writer`. This may or may not be what we want, but it at least
doesn't throw any errors encountered in later `Writer`s into oblivion.
* Prevent `IterReader`'s `Reader::read` impl from returning EOF if given
an empty buffer.
[breaking-change]
Put `Duration` in `time::duration`, where the two constants can
be called just `MAX` and `MIN`. Reexport from `time`.
This provides more room for the time module to expand.
