Similar to the stability attributes, a type annotated with `#[must_use =
"informative snippet"]` will print the normal warning message along with
"informative snippet". This allows the type author to provide some
guidance about why the type should be used.
---
It can be a little unintuitive that something like `v.iter().map(|x|
println!("{}", x));` does nothing: the majority of the iterator adaptors
are lazy and do not execute anything until something calls `next`, e.g.
a `for` loop, `collect`, `fold`, etc.
The majority of such errors can be seen by someone writing something
like the above, i.e. just calling an iterator adaptor and doing nothing
with it (and doing this is certainly useless), so we can co-opt the
`must_use` lint, using the message functionality to give a hint to the
reason why.
Fixes#14666.
Similar to the stability attributes, a type annotated with `#[must_use =
"informative snippet"]` will print the normal warning message along with
"informative snippet". This allows the type author to provide some
guidance about why the type should be used.
This shuffles things around a bit so that LIT_CHAR and co store an Ident
which is the original, unaltered literal in the source. When creating the AST,
unescape and postprocess them.
This changes how syntax extensions can work, slightly, but otherwise poses no
visible changes. To get a useful value out of one of these tokens, call
`parse::{char_lit, byte_lit, bin_lit, str_lit}`
[breaking-change]
This updates https://github.com/rust-lang/rust/pull/15075.
Rename `ToStr::to_str` to `ToString::to_string`. The naive renaming ends up with two `to_string` functions defined on strings in the prelude (the other defined via `collections::str::StrAllocating`). To remedy this I removed `StrAllocating::to_string`, making all conversions from `&str` to `String` go through `Show`. This has a measurable impact on the speed of this conversion, but the sense I get from others is that it's best to go ahead and unify `to_string` and address performance for all `to_string` conversions in `core::fmt`. `String::from_str(...)` still works as a manual fast-path.
Note that the patch was done with a script, and ended up renaming a number of other `*_to_str` functions, particularly inside of rustc. All the ones I saw looked correct, and I didn't notice any additional API breakage.
Closes#15046.
closes#13367
[breaking-change] Use `Sized?` to indicate a dynamically sized type parameter or trait (used to be `type`). E.g.,
```
trait Tr for Sized? {}
fn foo<Sized? X: Share>(x: X) {}
```
closes#13367
[breaking-change] Use `Sized?` to indicate a dynamically sized type parameter or trait (used to be `type`). E.g.,
```
trait Tr for Sized? {}
fn foo<Sized? X: Share>(x: X) {}
```
This will break code that looks like:
struct Foo {
...
}
mod Foo {
...
}
Change this code to:
struct Foo {
...
}
impl Foo {
...
}
Or rename the module.
Closes#15205.
[breaking-change]
r? @nick29581
Extend the null ptr optimization to work with slices, closures, procs, & trait objects by using the internal pointers as the discriminant.
This decreases the size of `Option<&[int]>` (and similar) by one word.
This will break code that used the old `Index` trait. Change this code
to use the new `Index` traits. For reference, here are their signatures:
pub trait Index<Index,Result> {
fn index<'a>(&'a self, index: &Index) -> &'a Result;
}
pub trait IndexMut<Index,Result> {
fn index_mut<'a>(&'a mut self, index: &Index) -> &'a mut Result;
}
Closes#6515.
[breaking-change]
r? @nick29581
This will break code that used the old `Index` trait. Change this code
to use the new `Index` traits. For reference, here are their signatures:
pub trait Index<Index,Result> {
fn index<'a>(&'a self, index: &Index) -> &'a Result;
}
pub trait IndexMut<Index,Result> {
fn index_mut<'a>(&'a mut self, index: &Index) -> &'a mut Result;
}
Closes#6515.
[breaking-change]
This will break code that looks like:
struct Foo {
...
}
mod Foo {
...
}
Change this code to:
struct Foo {
...
}
impl Foo {
...
}
Or rename the module.
Closes#15205.
[breaking-change]
I ran `make check` and everything went smoothly. I also tested `#[deriving(Decodable, Encodable)]` on a struct containing both Cell<T> and RefCell<T> and everything now seems to work fine.
In a cargo-driven world the primary location for the name of a crate will be in
its manifest, not in the source file itself. The purpose of this flag is to
reduce required duplication for new cargo projects.
This is a breaking change because the existing --crate-name flag actually
printed the crate name. This flag was renamed to --print-crate-name, and to
maintain consistence, the --crate-file-name flag was renamed to
--print-file-name.
To maintain backwards compatibility, the --crate-file-name flag is still
recognized, but it is deprecated.
[breaking-change]
This comit implements a new flag, --extern, which is used to specify where a
crate is located. The purpose of this flag is to bypass the normal crate
loading/matching of the compiler to point it directly at the right file.
This flag takes the form `--extern foo=bar` where `foo` is the name of a crate
and `bar` is the location at which to find the crate. Multiple `--extern`
directives are allowed with the same crate name to specify the rlib/dylib pair
for a crate. It is invalid to specify more than one rlib or more than one dylib,
and it's required that the crates are valid rust crates.
I have also added some extensive documentation to metadata::loader about how
crate loading should work.
RFC: 0035-remove-crate-id
The types `Bitv` and `BitvSet` are badly out of date. This PR:
- cleans up the code (primarily, simplifies `Bitv` and implements `BitvSet` in terms of `Bitv`)
- implements several new traits for `Bitv`
- adds new functionality to `Bitv` and `BitvSet`
- replaces internal iterators with external ones
- updates documentation
- minor bug fixes
This is a significantly souped-up version of PR #15139 and is the result of the discussion there.
This was parsed by the parser but completely ignored; not even stored in
the AST!
This breaks code that looks like:
static X: &'static [u8] = &'static [1, 2, 3];
Change this code to the shorter:
static X: &'static [u8] = &[1, 2, 3];
Closes#15312.
[breaking-change]
r? @nick29581
This was parsed by the parser but completely ignored; not even stored in
the AST!
This breaks code that looks like:
static X: &'static [u8] = &'static [1, 2, 3];
Change this code to the shorter:
static X: &'static [u8] = &[1, 2, 3];
Closes#15312.
[breaking-change]
parameters.
This can break code that mistakenly used type parameters in place of
`Self`. For example, this will break:
trait Foo {
fn bar<X>(u: X) -> Self {
u
}
}
Change this code to not contain a type error. For example:
trait Foo {
fn bar<X>(_: X) -> Self {
self
}
}
Closes#15172.
[breaking-change]
r? @alexcrichton
This can break code that looked like:
struct S<T> {
val: T,
}
trait Gettable<T> {
...
}
impl<T: Copy> Gettable<T> for S<T> {
...
}
let t: Box<S<String>> = box S {
val: "one".to_string(),
};
let a = t as Box<Gettable<String>>;
// ^ note no `Copy` bound
Change this code to:
impl<T> Gettable<T> for S<T> {
// ^ remove `Copy` bound
...
}
Closes#14061.
[breaking-change]
So far, type names generated for debuginfo where a bit sketchy. It was not clearly defined when a name should be fully qualified and when not, if region parameters should be shown or not, and other things like that.
This commit makes the debuginfo module responsible for creating type names instead of using `ppaux::ty_to_str()` and brings type names (as they show up in the DWARF information) in line with GCC and Clang:
* The name of the type being described is unqualified. It's path is defined by its position in the namespace hierarchy.
* Type arguments are always fully qualified, no matter if they would actually be in scope at the type definition location.
Care is also taken to make type names consistent across crate boundaries. That is, the code now tries make the type name the same, regardless if the type is in the local crate or reconstructed from metadata. Otherwise LLVM will complain about violating the one-definition-rule when using link-time-optimization.
This commit also removes all source location information from type descriptions because these cannot be reconstructed for types instantiated from metadata. Again, with LTO enabled, this can lead to two versions of the debuginfo type description, one with and one without source location information, which then triggers the LLVM ODR assertion.
Fortunately, source location information about types is rarely used, so this has little impact. Once source location information is preserved in metadata (#1972) it can also be re-enabled for type descriptions.
`RUSTFLAGS=-g make check` no works again for me locally, including the LTO test cases (note that I've taken care of #15156 by reverting the change in LLVM that @luqmana identified as the culprit for that issue).
