C structs predominately do not use camel case identifiers, and we have a clear
indicator for what's a C struct now, so excuse all of them from this stylistic
lint.
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 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) {}
```
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
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]
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]
with the corresponding trait parameter bounds.
This is a version of the patch in PR #12611 by Florian Hahn, modified to
address Niko's feedback.
It does not address the issue of duplicate type parameter bounds, nor
does it address the issue of implementation-defined methods that contain
*fewer* bounds than the trait, because Niko's review indicates that this
should not be necessary (and indeed I believe it is not). A test has
been added to ensure that this works.
This will break code like:
trait Foo {
fn bar<T:Baz>();
}
impl Foo for Boo {
fn bar<T:Baz + Quux>() { ... }
// ^~~~ ERROR
}
This will be rejected because the implementation requires *more* bounds
than the trait. It can be fixed by either adding the missing bound to
the trait:
trait Foo {
fn bar<T:Baz + Quux>();
// ^~~~
}
impl Foo for Boo {
fn bar<T:Baz + Quux>() { ... } // OK
}
Or by removing the bound from the impl:
trait Foo {
fn bar<T:Baz>();
}
impl Foo for Boo {
fn bar<T:Baz>() { ... } // OK
// ^ remove Quux
}
This patch imports the relevant tests from #2687, as well as the test
case in #5886, which is fixed as well by this patch.
Closes#2687.
Closes#5886.
[breaking-change]
r? @pnkfelix
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]
Slice patterns are different from the rest in that a single slice pattern
does not have a distinct constructor if it contains a variable-length subslice
pattern. For example, the pattern [a, b, ..tail] can match a slice of length 2, 3, 4
and so on.
As a result, the decision tree for exhaustiveness and redundancy analysis should
explore each of those constructors separately to determine if the pattern could be useful
when specialized for any of them.
with the corresponding trait parameter bounds.
This is a version of the patch in PR #12611 by Florian Hahn, modified to
address Niko's feedback.
It does not address the issue of duplicate type parameter bounds, nor
does it address the issue of implementation-defined methods that contain
*fewer* bounds than the trait, because Niko's review indicates that this
should not be necessary (and indeed I believe it is not). A test has
been added to ensure that this works.
This will break code like:
trait Foo {
fn bar<T:Baz>();
}
impl Foo for Boo {
fn bar<T:Baz + Quux>() { ... }
// ^~~~ ERROR
}
This will be rejected because the implementation requires *more* bounds
than the trait. It can be fixed by either adding the missing bound to
the trait:
trait Foo {
fn bar<T:Baz + Quux>();
// ^~~~
}
impl Foo for Boo {
fn bar<T:Baz + Quux>() { ... } // OK
}
Or by removing the bound from the impl:
trait Foo {
fn bar<T:Baz>();
}
impl Foo for Boo {
fn bar<T:Baz>() { ... } // OK
// ^ remove Quux
}
This patch imports the relevant tests from #2687, as well as the test
case in #5886, which is fixed as well by this patch.
Closes#2687.
Closes#5886.
[breaking-change]
Being able to index into the bytes of a string encourages
poor UTF-8 hygiene. To get a view of `&[u8]` from either
a `String` or `&str` slice, use the `as_bytes()` method.
Closes#12710.
[breaking-change]
I ended up altering the semantics of Json's PartialOrd implementation.
It used to be the case that Null < Null, but I can't think of any reason
for an ordering other than the default one so I just switched it over to
using the derived implementation.
This also fixes broken `PartialOrd` implementations for `Vec` and
`TreeMap`.
RFC: 0028-partial-cmp
floating point numbers for real.
This will break code that looks like:
let mut x = 0;
while ... {
x += 1;
}
println!("{}", x);
Change that code to:
let mut x = 0i;
while ... {
x += 1;
}
println!("{}", x);
Closes#15201.
[breaking-change]
This change registers new snapshots, allowing `*T` to be removed from the language. This is a large breaking change, and it is recommended that if compiler errors are seen that any FFI calls are audited to determine whether they should be actually taking `*mut T`.
I believe that #5781 got fixed by the DST work. It duplicated the
variance inference work in #12828. Therefore, all that is left in #5781
is adding a test.
Closes#5781.
r? @huonw
This can break code that looked like:
impl Foo for Box<Any> {
fn f(&self) { ... }
}
let x: Box<Any + Send> = ...;
x.f();
Change such code to:
impl Foo for Box<Any> {
fn f(&self) { ... }
}
let x: Box<Any> = ...;
x.f();
That is, upcast before calling methods.
This is a conservative solution to #5781. A more proper treatment (see
the xfail'd `trait-contravariant-self.rs`) would take variance into
account. This change fixes the soundness hole.
Some library changes had to be made to make this work. In particular,
`Box<Any>` is no longer showable, and only `Box<Any+Send>` is showable.
Eventually, this restriction can be lifted; for now, it does not prove
too onerous, because `Any` is only used for propagating the result of
task failure.
This patch also adds a test for the variance inference work in #12828,
which accidentally landed as part of DST.
Closes#5781.
[breaking-change]
Since procs do not have lifetime bounds, we must do this to maintain
safety.
This can break code that incorrectly captured references in procedure
types. Change such code to not do this, perhaps with a trait object
instead.
A better solution would be to add higher-rank lifetime support to procs.
However, this would be a lot of work for a feature we want to remove in
favor of unboxed closures. The corresponding "real fix" is #15067.
Closes#14036.
[breaking-change]
It turns out that bindings introduced by 'for' loops were not treated hygienically. The fix for this is to make the 'for' expansion more like a macro; rather than expanding sub-pieces and then assembling them, we need to rewrite the for and then call expand again on the whole thing.
This PR includes a test and the fix.
It also contains a number of other things:
- unit tests for other forms of hygiene (currently ignored)
- a fix for the isaac.rs macro that (it turned out) was relying on capturing
- other miscellaneous cleanup and comments
This will break code like:
fn f(x: &mut int) {}
let mut a = box 1i;
f(a);
Change it to:
fn f(x: &mut int) {}
let mut a = box 1i;
f(&mut *a);
RFC 33; issue #10504.
[breaking-change]
r? @brson
vector-reference-to-unsafe-pointer-to-element cast if the type to be
casted to is not fully specified.
This is a conservative change to fix the user-visible symptoms of the
issue. A more flexible treatment would delay cast checks to after
function typechecking.
This can break code that did:
let x: *u8 = &([0, 0]) as *_;
Change this code to:
let x: *u8 = &([0, 0]) as *u8;
Closes#14893.
[breaking-change]
This will break code like:
fn f(x: &mut int) {}
let mut a = box 1i;
f(a);
Change it to:
fn f(x: &mut int) {}
let mut a = box 1i;
f(&mut *a);
RFC 33; issue #10504.
[breaking-change]
Closes#14482 (std: Bring back half of Add on String)
Closes#15026 (librustc: Remove the fallback to `int` from typechecking.)
Closes#15119 (Add more description to c_str::unwrap().)
Closes#15120 (Add tests for #12470 and #14285)
Closes#15122 (Remove the cheat sheet.)
Closes#15126 (rustc: Always include the morestack library)
Closes#15127 (Improve ambiguous pronoun.)
Closes#15130 (Fix#15129)
Closes#15131 (Add the Guide, add warning to tutorial.)
Closes#15134 (Xfailed tests for hygiene, etc.)
Closes#15135 (core: Add stability attributes to Clone)
Closes#15136 (Some minor improvements to core::bool)
Closes#15137 (std: Add stability attributes to primitive numeric modules)
Closes#15141 (Fix grammar in tutorial)
Closes#15143 (Remove few FIXMEs)
Closes#15145 (Avoid unnecessary temporary on assignments)
Closes#15147 (Small improvements for metaprogramming)
Closes#15153 (librustc: Check function argument patterns for legality of by-move)
Closes#15154 (test: Add a test for regions, traits, and variance.)
Closes#15159 (rustc: Don't register syntax crates twice)
Closes#13816 (Stabilize version output for rustc and rustdoc)
bindings.
This will break code that incorrectly did things like:
fn f(a @ box b: Box<String>) {}
Fix such code to not rely on undefined behavior.
Closes#12534.
[breaking-change]
The #14869 removed `TraitStore` from `ty_trait` and represented trait
reference as regular `ty_rptr`. An old bug of the missing constraint
upon lifetime parameter of trait reference then is fixed as a side
effect. Adds tests for affected bugs and closes them.
Closes#12470.
Closes#14285.
This breaks a fair amount of code. The typical patterns are:
* `for _ in range(0, 10)`: change to `for _ in range(0u, 10)`;
* `println!("{}", 3)`: change to `println!("{}", 3i)`;
* `[1, 2, 3].len()`: change to `[1i, 2, 3].len()`.
RFC #30. Closes#6023.
[breaking-change]
If you define lang items in your crate, add `#[feature(lang_items)]`.
If you define intrinsics (`extern "rust-intrinsic"`), add
`#[feature(intrinsics)]`.
Closes#12858.
[breaking-change]
Unit-like structs are written as `struct Foo;`, but we erroneously
accepted `struct Foo();` and took it to mean the same thing. Now we
don't, so use the `struct Foo;` form!
[breaking-change]
This commit makes several changes to the stability index infrastructure:
* Stability levels are now inherited lexically, i.e., each item's
stability level becomes the default for any nested items.
* The computed stability level for an item is stored as part of the
metadata. When using an item from an external crate, this data is
looked up and cached.
* The stability lint works from the computed stability level, rather
than manual stability attribute annotations. However, the lint still
checks only a limited set of item uses (e.g., it does not check every
component of a path on import). This will be addressed in a later PR,
as part of issue #8962.
* The stability lint only applies to items originating from external
crates, since the stability index is intended as a promise to
downstream crates.
* The "experimental" lint is now _allow_ by default. This is because
almost all existing crates have been marked "experimental", pending
library stabilization. With inheritance in place, this would generate
a massive explosion of warnings for every Rust program.
The lint should be changed back to deny-by-default after library
stabilization is complete.
* The "deprecated" lint still warns by default.
The net result: we can begin tracking stability index for the standard
libraries as we stabilize, without impacting most clients.
Closes#13540.
This PR is changing the error messages for non-exhaustive pattern matching to include a more accurate witness, i.e. a pattern that is not covered by any of the ones provided by the user. Example:
```rust
fn main() {
match (true, (Some("foo"), [true, true]), Some(42u)) {
(false, _, _) => (),
(true, (None, [true, _]), None) => (),
(true, (None, [false, _]), Some(1u)) => ()
}
}
```
```sh
/tmp/witness.rs:2:2: 6:3 error: non-exhaustive patterns: (true, (core::option::Some(_), _), _) not covered
/tmp/witness.rs:2 match (true, (Some("foo"), [true, true]), Some(42u)) {
/tmp/witness.rs:3 (false, _, _) => (),
/tmp/witness.rs:4 (true, (None, [true, _]), None) => (),
/tmp/witness.rs:5 (true, (None, [false, _]), Some(1u)) => ()
/tmp/witness.rs:6 }
```
As part of that, I refactored some of the relevant code and carried over the changes to fixed vectors from the previous PR.
I'm putting it out there for now but the tests will be red.
Closes#8142.
This is not the semantics we want long-term. You can continue to use
`#[unsafe_destructor]`, but you'll need to add
`#![feature(unsafe_destructor)]` to the crate attributes.
[breaking-change]
This commit makes several changes to the stability index infrastructure:
* Stability levels are now inherited lexically, i.e., each item's
stability level becomes the default for any nested items.
* The computed stability level for an item is stored as part of the
metadata. When using an item from an external crate, this data is
looked up and cached.
* The stability lint works from the computed stability level, rather
than manual stability attribute annotations. However, the lint still
checks only a limited set of item uses (e.g., it does not check every
component of a path on import). This will be addressed in a later PR,
as part of issue #8962.
* The stability lint only applies to items originating from external
crates, since the stability index is intended as a promise to
downstream crates.
* The "experimental" lint is now _allow_ by default. This is because
almost all existing crates have been marked "experimental", pending
library stabilization. With inheritance in place, this would generate
a massive explosion of warnings for every Rust program.
The lint should be changed back to deny-by-default after library
stabilization is complete.
* The "deprecated" lint still warns by default.
The net result: we can begin tracking stability index for the standard
libraries as we stabilize, without impacting most clients.
Closes#13540.
The lexer already ignores CRLF in between tokens, but it doesn't
properly handle carriage returns inside strings and doc comments. Teach
it to treat CRLF as LF inside these tokens, and to disallow carriage
returns that are not followed by linefeeds. This includes handling an
escaped CRLF inside a regular string token the same way it handles an
escaped LF.
This is technically a breaking change, as bare carriage returns are no
longer allowed, and CRLF sequences are now treated as LF inside strings
and doc comments, but it's very unlikely to actually affect any
real-world code.
This change is necessary to have Rust code compile on Windows the same
way it does on Unix. The mozilla/rust repository explicitly sets eol=lf
for Rust source files, but other Rust repositories don't. Notably,
rust-http cannot be compiled on Windows without converting the CRLF line
endings back to LF.
[breaking-change]
The lexer already ignores CRLF in between tokens, but it doesn't
properly handle carriage returns inside strings and doc comments. Teach
it to treat CRLF as LF inside these tokens, and to disallow carriage
returns that are not followed by linefeeds. This includes handling an
escaped CRLF inside a regular string token the same way it handles an
escaped LF.
This is technically a breaking change, as bare carriage returns are no
longer allowed, and CRLF sequences are now treated as LF inside strings
and doc comments, but it's very unlikely to actually affect any
real-world code.
This change is necessary to have Rust code compile on Windows the same
way it does on Unix. The mozilla/rust repository explicitly sets eol=lf
for Rust source files, but other Rust repositories don't. Notably,
rust-http cannot be compiled on Windows without converting the CRLF line
endings back to LF.
[breaking-change]
Replace its usage with byte string literals, except in `bytes!()` tests.
Also add a new snapshot, to be able to use the new b"foo" syntax.
The src/etc/2014-06-rewrite-bytes-macros.py script automatically
rewrites `bytes!()` invocations into byte string literals.
Pass it filenames as arguments to generate a diff that you can inspect,
or `--apply` followed by filenames to apply the changes in place.
Diffs can be piped into `tip` or `pygmentize -l diff` for coloring.
thereof.)
PR 14739 injected the new message that this removes from one test
case: borrowck-vec-pattern-loan-from-mut.rs
When reviewing the test case, I was not able to convince myself that
the error message was a legitimate thing to start emitting. Niko did
not see an obvious reason for it either, so I am going to remove it
and wait for someone (maybe Cameron Zwarich) to explain to me why we
should be emitting it.
