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## Summary Allow renaming imports when importing a group of symbols from a module. ```rust use std::io::{ Error as IoError, Result as IoResult, Read, Write } ``` ## Motivation The current design requires the above example to be written like...
## Summary Remove panics from `CString::from_slice` and `CString::from_vec`, making these functions return `Result` instead. ## Motivation > As I shivered and brooded on the casting of that brain-blasting shadow, > I knew that I had at last...
## Summary Make all collections `impl<'a, T: Copy> Extend<&'a T>`. This enables both `vec.extend(&[1, 2, 3])`, and `vec.extend(&hash_set_of_ints)`. This partially covers the usecase of the awkward `Vec::push_all` with literally no ergonomic...
## Summary Add a default lifetime bound for object types, so that it is no longer necessary to write things like `Box<Trait+'static>` or `&'a (Trait+'a)`. The default will be based on the context in which the object type appears. Typically,...
## Summary Add back the functionality of `Vec::from_elem` by improving the `vec![x; n]` sugar to work with Clone `x` and runtime `n`. ## Motivation High demand, mostly. There are currently a few ways to achieve the behaviour of `Vec::from_e...
## Summary [summary]: #summary The current compiler implements a more expansive semantics for pattern matching than was originally intended. This RFC introduces several mechanisms to reign in these semantics without actually breaking (much,...
## This RFC was previously approved, but later **withdrawn** For details see the [summary comment]. [summary comment]: https://github.com/rust-lang/rust/issues/27779#issuecomment-378416911 ## Summary * Change placement-new syntax from: `box...
## Summary Rust currently includes feature-gated support for type parameters that specify a default value. This feature is not well-specified. The aim of this RFC is to fully specify the behavior of defaulted type parameters: 1. Type parame...
## Summary Add type ascription to expressions. (An earlier version of this RFC covered type ascription in patterns too, that has been postponed). Type ascription on expression has already been implemented. See also discussion on [#354](http...
## Summary Add a `once` function to `std::iter` to construct an iterator yielding a given value one time, and an `empty` function to construct an iterator yielding no values. ## Motivation This is a common task when working with iterators....
## Summary Change Functional Record Update (FRU) for struct literal expressions to respect struct privacy. ## Motivation Functional Record Update is the name for the idiom by which one can write `..<expr>` at the end of a struct literal exp...
## Summary The `Fn` traits should be modified to make the return type an associated type. ## Motivation The strongest reason is because it would permit impls like the following (example from @alexcrichton): ```rust impl<R,F> Foo for F : FnM...
## Summary Add the syntax `..` for `std::ops::RangeFull`. ## Motivation Range expressions `a..b`, `a..` and `..b` all have dedicated syntax and produce first-class values. This means that they will be usable and useful in custom APIs, so fo...
## Summary Add a new intrinsic, `discriminant_value` that extracts the value of the discriminant for enum types. ## Motivation Many operations that work with discriminant values can be significantly improved with the ability to extract the...
## Summary The `Debug` trait is intended to be implemented by every type and display useful runtime information to help with debugging. This RFC proposes two additions to the fmt API, one of which aids implementors of `Debug`, and one which...
## Summary Rename the `be` reserved keyword to `become`. ## Motivation A keyword needs to be reserved to support guaranteed tail calls in a backward-compatible way. Currently the keyword reserved for this purpose is `be`, but the `become` a...
## Summary Make `Self` a keyword. ## Motivation Right now, `Self` is just a regular identifier that happens to get a special meaning inside trait definitions and impls. Specifically, users are not forbidden from defining a type called `Self...
## Summary Make `CString` dereference to a token type `CStr`, which designates null-terminated string data. ```rust // Type-checked to only accept C strings fn safe_puts(s: &CStr) { unsafe { libc::puts(s.as_ptr()) }; } fn main() { let s = C...
## Summary Rename (maybe one of) the standard collections, so as to make the names more consistent. Currently, among all the alternatives, renaming `BinaryHeap` to `BinHeap` is the slightly preferred solution. ## Motivation In [this comment...
## Summary Replace `Vec::drain` by a method that accepts a range parameter. Add `String::drain` with similar functionality. ## Motivation Allowing a range parameter is strictly more powerful than the current version. E.g., see the following...
"Rust is 5 languages stacked on top of each other, except that instead of ending up like 5 children under a trenchcoat, they end up like the power rang..."