The previous syntax was `Foo:Bound<trait-parameters>`, but this is a little
ambiguous because it was being parsed as `Foo: (Bound<trait-parameters)` rather
than `Foo: (Bound) <trait-parameters>`
This commit changes the syntax to `Foo<trait-parameters>: Bound` in order to be
clear where the trait parameters are going.
Closes#9265
It was possible to borrow unsafe static items in static initializers.
This patch implements a small `Visitor` that walks static initializer's
expressions and checks borrows aliasability.
Fixes#13005
cc @nikomatsakis r?
* Remove clone-ability from all primitives. All shared state will now come
from the usage of the primitives being shared, not the primitives being
inherently shareable. This allows for fewer allocations for stack-allocated
primitives.
* Add `Mutex<T>` and `RWLock<T>` which are stack-allocated primitives for purely
wrapping a piece of data
* Remove `RWArc<T>` in favor of `Arc<RWLock<T>>`
* Remove `MutexArc<T>` in favor of `Arc<Mutex<T>>`
* Shuffle around where things are located
* The `arc` module now only contains `Arc`
* A new `lock` module contains `Mutex`, `RWLock`, and `Barrier`
* A new `raw` module contains the primitive implementations of `Semaphore`,
`Mutex`, and `RWLock`
* The Deref/DerefMut trait was implemented where appropriate
* `CowArc` was removed, the functionality is now part of `Arc` and is tagged
with `#[experimental]`.
* The crate now has #[deny(missing_doc)]
* `Arc` now supports weak pointers
This is not a large-scale rewrite of the functionality contained within the
`sync` crate, but rather a shuffling of who does what an a thinner hierarchy of
ownership to allow for better composability.
Summary:
It was possible to borrow unsafe static items in static initializers.
This patch implements a small `Visitor` that walks static initializer's
expressions and checks borrows aliasability.
Fixes#13005
Test Plan: make check
Differential Revision: http://phabricator.octayn.net/D2
syntax: allow `trace_macros!` and `log_syntax!` in item position.
Previously
trace_macros!(true)
fn main() {}
would complain about `trace_macros` being an expression macro in item
position. This is a pointless limitation, because the macro is purely
compile-time, with no runtime effect. (And similarly for log_syntax.)
This also changes the behaviour of `trace_macros!` very slightly, it
used to be equivalent to
macro_rules! trace_macros {
(true $($_x: tt)*) => { true };
(false $($_x: tt)*) => { false }
}
I.e. you could invoke it with arbitrary trailing arguments, which were
ignored. It is changed to accept only exactly `true` or `false` (with no
trailing arguments) and expands to `()`.
Previously
trace_macros!(true)
fn main() {}
would complain about `trace_macros` being an expression macro in item
position. This is a pointless limitation, because the macro is purely
compile-time, with no runtime effect. (And similarly for log_syntax.)
This also changes the behaviour of `trace_macros!` very slightly, it
used to be equivalent to
macro_rules! trace_macros {
(true $($_x: tt)*) => { true };
(false $($_x: tt)*) => { false }
}
I.e. you could invoke it with arbitrary trailing arguments, which were
ignored. It is changed to accept only exactly `true` or `false` (with no
trailing arguments) and expands to `()`.
`Share` implies that all *reachable* content is *threadsafe*.
Threadsafe is defined as "exposing no operation that permits a data race if multiple threads have access to a &T pointer simultaneously". (NB: the type system should guarantee that if you have access to memory via a &T pointer, the only other way to gain access to that memory is through another &T pointer)...
Fixes#11781
cc #12577
What this PR will do
================
- [x] Add Share kind and
- [x] Replace usages of Freeze with Share in bounds.
- [x] Add Unsafe<T> #12577
- [x] Forbid taking the address of a immutable static item with `Unsafe<T>` interior
What's left to do in a separate PR (after the snapshot)?
===========================================
- Remove `Freeze` completely
This is adequate because when a function has a type that isn't caught here,
that is, it has a single argument, but it *isn't* `&mut BenchHarness`, it
errors later on with:
error: mismatched types: expected `fn(&mut test::BenchHarness)` but found
`fn(int)` (expected &-ptr but found int)
which I consider acceptable.
Closes#12997
This PR enables the use of mutable slices in *mutable* static items. The work was started by @xales and I added a follow-up commit that moves the *immutable* restriction to the recently added `check_static`
Closes#11411
its a common (yet easily fixable) error to just forget parens at the end of getter-like methods without any arguments.
The current error message for that case asks for an anonymous function, this patch adds a note asking for either an anonymous function, or for trailing parens.
This is my first contribution! do i need to do anything else?
This commit moves all logging out of the standard library into an external
crate. This crate is the new crate which is responsible for all logging macros
and logging implementation. A few reasons for this change are:
* The crate map has always been a bit of a code smell among rust programs. It
has difficulty being loaded on almost all platforms, and it's used almost
exclusively for logging and only logging. Removing the crate map is one of the
end goals of this movement.
* The compiler has a fair bit of special support for logging. It has the
__log_level() expression as well as generating a global word per module
specifying the log level. This is unfairly favoring the built-in logging
system, and is much better done purely in libraries instead of the compiler
itself.
* Initialization of logging is much easier to do if there is no reliance on a
magical crate map being available to set module log levels.
* If the logging library can be written outside of the standard library, there's
no reason that it shouldn't be. It's likely that we're not going to build the
highest quality logging library of all time, so third-party libraries should
be able to provide just as high-quality logging systems as the default one
provided in the rust distribution.
With a migration such as this, the change does not come for free. There are some
subtle changes in the behavior of liblog vs the previous logging macros:
* The core change of this migration is that there is no longer a physical
log-level per module. This concept is still emulated (it is quite useful), but
there is now only a global log level, not a local one. This global log level
is a reflection of the maximum of all log levels specified. The previously
generated logging code looked like:
if specified_level <= __module_log_level() {
println!(...)
}
The newly generated code looks like:
if specified_level <= ::log::LOG_LEVEL {
if ::log::module_enabled(module_path!()) {
println!(...)
}
}
Notably, the first layer of checking is still intended to be "super fast" in
that it's just a load of a global word and a compare. The second layer of
checking is executed to determine if the current module does indeed have
logging turned on.
This means that if any module has a debug log level turned on, all modules
with debug log levels get a little bit slower (they all do more expensive
dynamic checks to determine if they're turned on or not).
Semantically, this migration brings no change in this respect, but
runtime-wise, this will have a perf impact on some code.
* A `RUST_LOG=::help` directive will no longer print out a list of all modules
that can be logged. This is because the crate map will no longer specify the
log levels of all modules, so the list of modules is not known. Additionally,
warnings can no longer be provided if a malformed logging directive was
supplied.
The new "hello world" for logging looks like:
#[phase(syntax, link)]
extern crate log;
fn main() {
debug!("Hello, world!");
}
This commit shreds all remnants of libextra from the compiler and standard
distribution. Two modules, c_vec/tempfile, were moved into libstd after some
cleanup, and the other modules were moved to separate crates as seen fit.
Closes#8784Closes#12413Closes#12576
lint: add lint for use of a `~[T]`.
This is useless at the moment (since pretty much every crate uses
`~[]`), but should help avoid regressions once completely removed from a
crate.
## read+write modifier '+'
This small sugar was left out in the original implementation (#5359).
When an output operand with the '+' modifier is encountered, we store the index of that operand alongside the expression to create and append an input operand later. The following lines are equivalent:
```
asm!("" : "+m"(expr));
asm!("" : "=m"(expr) : "0"(expr));
```
## misplaced options and clobbers give a warning
It's really annoying when a small typo might change behavior without any warning.
```
asm!("mov $1, $0" : "=r"(x) : "r"(8u) : "cc" , "volatile");
//~^ WARNING expected a clobber, but found an option
```
## liveness
Fixed incorrect order of propagation.
Sometimes it caused spurious warnings in code: `warning: value assigned to `i` is never read, #[warn(dead_assignment)] on by default`
~~Note: Rebased on top of another PR. (uses other changes)~~
* [x] Implement read+write
* [x] Warn about misplaced options
* [x] Fix liveness (`dead_assignment` lint)
* [x] Add all tests
For the following code snippet:
```rust
struct Foo { bar: int }
fn foo1(x: &Foo) -> &int {
&x.bar
}
```
This PR generates the following error message:
```rust
test.rs:2:1: 4:2 note: consider using an explicit lifetime parameter as shown: fn foo1<'a>(x: &'a Foo) -> &'a int
test.rs:2 fn foo1(x: &Foo) -> &int {
test.rs:3 &x.bar
test.rs:4 }
test.rs:3:5: 3:11 error: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements
test.rs:3 &x.bar
^~~~~~
```
Currently it does not support methods.
The `~str` type is not long for this world as it will be superseded by the
soon-to-come DST changes for the language. The new type will be
`~Str`, and matching over the allocation will no longer be supported.
Matching on `&str` will continue to work, in both a pre and post DST world.
Some types of error are caused by missing lifetime parameter on function
or method declaration. In such cases, this commit generates some
suggestion about what the function declaration could be. This does not
support method declaration yet.
This is needed to make progress on #10296 as the default bounds will no longer
include Send. I believe that this was the originally intended syntax for procs,
and it just hasn't been necessary up until now.
This is needed to make progress on #10296 as the default bounds will no longer
include Send. I believe that this was the originally intended syntax for procs,
and it just hasn't been necessary up until now.
This functionality is not super-core and so doesn't need to be included
in std. It's possible that std may need rand (it does a little bit now,
for io::test) in which case the functionality required could be moved to
a secret hidden module and reexposed by librand.
Unfortunately, using #[deprecated] here is hard: there's too much to
mock to make it feasible, since we have to ensure that programs still
typecheck to reach the linting phase.
It is often convenient to have forms of weak linkage or other various types of
linkage. Sadly, just using these flavors of linkage are not compatible with
Rust's typesystem and how it considers some pointers to be non-null.
As a compromise, this commit adds support for weak linkage to external symbols,
but it requires that this is only placed on extern statics of type `*T`.
Codegen-wise, we get translations like:
```rust
// rust code
extern {
#[linkage = "extern_weak"]
static foo: *i32;
}
// generated IR
@foo = extern_weak global i32
@_some_internal_symbol = internal global *i32 @foo
```
All references to the rust value of `foo` then reference `_some_internal_symbol`
instead of the symbol `_foo` itself. This allows us to guarantee that the
address of `foo` will never be null while the value may sometimes be null.
An example was implemented in `std::rt::thread` to determine if
`__pthread_get_minstack()` is available at runtime, and a test is checked in to
use it for a static value as well. Function pointers a little odd because you
still need to transmute the pointer value to a function pointer, but it's
thankfully better than not having this capability at all.
Thanks to @bnoordhuis for the original patch, most of this work is still his!
It is often convenient to have forms of weak linkage or other various types of
linkage. Sadly, just using these flavors of linkage are not compatible with
Rust's typesystem and how it considers some pointers to be non-null.
As a compromise, this commit adds support for weak linkage to external symbols,
but it requires that this is only placed on extern statics of type `*T`.
Codegen-wise, we get translations like:
// rust code
extern {
#[linkage = "extern_weak"]
static foo: *i32;
}
// generated IR
@foo = extern_weak global i32
@_some_internal_symbol = internal global *i32 @foo
All references to the rust value of `foo` then reference `_some_internal_symbol`
instead of the symbol `_foo` itself. This allows us to guarantee that the
address of `foo` will never be null while the value may sometimes be null.
An example was implemented in `std::rt::thread` to determine if
`__pthread_get_minstack()` is available at runtime, and a test is checked in to
use it for a static value as well. Function pointers a little odd because you
still need to transmute the pointer value to a function pointer, but it's
thankfully better than not having this capability at all.
Closes#1433. Implemented after suggestion by @cmr in #12323
This is slightly less flexible than the implementation in #12323 (binary and octal floats aren't supported, nor are underscores in the literal), but is cleaner in that it doesn't modify the core grammar, or require odd syntax for the number itself. The missing features could be added back with relatively little effort (the main awkwardness is parsing the string. Is there a good approach for this in the stdlib currently?)
- Repurposes `MoveData.assignee_ids` to mean only `=` but not `+=`, so
that borrowck effectively classifies all expressions into assignees,
uses or both.
- Removes two `span_err` in liveness analysis, which are now borrowck's
responsibilities.
Closes#12527.
* `Ord` inherits from `Eq`
* `TotalOrd` inherits from `TotalEq`
* `TotalOrd` inherits from `Ord`
* `TotalEq` inherits from `Eq`
This is a partial implementation of #12517.
This new SVH is used to uniquely identify all crates as a snapshot in time of
their ABI/API/publicly reachable state. This current calculation is just a hash
of the entire crate's AST. This is obviously incorrect, but it is currently the
reality for today.
This change threads through the new Svh structure which originates from crate
dependencies. The concept of crate id hash is preserved to provide efficient
matching on filenames for crate loading. The inspected hash once crate metadata
is opened has been changed to use the new Svh.
The goal of this hash is to identify when upstream crates have changed but
downstream crates have not been recompiled. This will prevent the def-id drift
problem where upstream crates were recompiled, thereby changing their metadata,
but downstream crates were not recompiled.
In the future this hash can be expanded to exclude contents of the AST like doc
comments, but limitations in the compiler prevent this change from being made at
this time.
Closes#10207
These are types that are in exported type signatures, but are not
exported themselves, e.g.
struct Foo { ... }
pub fn bar() -> Foo { ... }
will warn about the Foo.
Such types are not listed in documentation, and cannot be named outside
the crate in which they are declared, which is very user-unfriendly.
cc #10573
- For each *mutable* static item, check that the **type**:
- cannot own any value whose type has a dtor
- cannot own any values whose type is an owned pointer
- For each *immutable* static item, check that the **value**:
- does not contain any ~ or box expressions
(including ~[1, 2, 3] sort of things)
- does not contain a struct literal or call to an enum
variant / struct constructor where
- the type of the struct/enum has a dtor
This updates a number of ignore-test tests, and removes a few completely
outdated tests due to the feature being tested no longer being supported.
This brings a number of bench/shootout tests up to date so they're compiling
again. I make no claims to the performance of these benchmarks, it's just nice
to not have bitrotted code.
Closes#2604Closes#9407
In its first pass, namely gather_loans, the borrow checker tracks the
initialization sites among other things it does. It does so for let
bindings with initializers but not for bindings in match arms, which are
effectively also assignments. This patch does that for borrow checker.
Closes#12452.
* compile-fail/vec-add.rs is obsolete, there are no mutable
vectors any more, #2711 is closed
* compile-fail/issue-1451.rs is obsolete, there are no more
structural records, #1451 is closed
* compile-fail/issue-2074.rs is obsolete, an up to date test
is in run-pass/nested-enum-same-names.rs, #2074 is closed
* compile-fail/omitted-arg-wrong-types.rs is obsolete, #2093
is closed
This commit removes deriving(ToStr) in favor of deriving(Show), migrating all impls of ToStr to fmt::Show.
Most of the details can be found in the first commit message.
Closes#12477
This commit changes the ToStr trait to:
impl<T: fmt::Show> ToStr for T {
fn to_str(&self) -> ~str { format!("{}", *self) }
}
The ToStr trait has been on the chopping block for quite awhile now, and this is
the final nail in its coffin. The trait and the corresponding method are not
being removed as part of this commit, but rather any implementations of the
`ToStr` trait are being forbidden because of the generic impl. The new way to
get the `to_str()` method to work is to implement `fmt::Show`.
Formatting into a `&mut Writer` (as `format!` does) is much more efficient than
`ToStr` when building up large strings. The `ToStr` trait forces many
intermediate allocations to be made while the `fmt::Show` trait allows
incremental buildup in the same heap allocated buffer. Additionally, the
`fmt::Show` trait is much more extensible in terms of interoperation with other
`Writer` instances and in more situations. By design the `ToStr` trait requires
at least one allocation whereas the `fmt::Show` trait does not require any
allocations.
Closes#8242Closes#9806
Makes labelled loops hygiene by performing renaming of the labels
defined in e.g. `'x: loop { ... }` and then used in break and continue
statements within loop body so that they act hygienically when used with
macros.
Closes#12262.
With the stability attributes we can put public-but unstable modules next to others, so this moves `intrinsics` and `raw` out of the `unstable` module (and marks both as `#[experimental]`).
These two containers are indeed collections, so their place is in
libcollections, not in libstd. There will always be a hash map as part of the
standard distribution of Rust, but by moving it out of the standard library it
makes libstd that much more portable to more platforms and environments.
This conveniently also removes the stuttering of 'std::hashmap::HashMap',
although 'collections::HashMap' is only one character shorter.
This PR merges `IterBytes` and `Hash` into a trait that allows for generic non-stream-based hashing. It makes use of @eddyb's default type parameter support in order to have a similar usage to the old `Hash` framework.
Fixes#8038.
Todo:
- [x] Better documentation
- [ ] Benchmark
- [ ] Parameterize `HashMap` on a `Hasher`.
Fixes#12350.
Parentheses around assignment statements such as
```rust
let mut a = (0);
a = (1);
a += (2);
```
are not necessary and therefore an unnecessary_parens warning is raised when
statements like this occur.
NOTE: In `let` declarations this does not work as intended. Is it possible that they do not count as assignment expressions (`ExprAssign`)? (edit: this is fixed by now)
Furthermore, there are some cases that I fixed in the rest of the code, where parentheses could potentially enhance readability. Compare these lines:
```rust
a = b == c;
a = (b == c);
```
Thus, after having worked on this I'm not entirely sure, whether we should go through with this patch or not. Probably a matter of debate. ;)
Not all of those messages are covered by tests. I am not sure how to trigger them and where to put those tests.
Also some message patterns in the existing tests are not complete.
For example, i find `error: mismatched types: expected "i32" but found "char" (expected i32 but found char)` a bit repetitive, but as i can see there is no test covering that.
Closes#12366.
Parentheses around assignment statements such as
let mut a = (0);
a = (1);
a += (2);
are not necessary and therefore an unnecessary_parens warning is raised when
statements like this occur.
The warning mechanism was refactored along the way to allow for code reuse
between the routines for checking expressions and statements.
Code had to be adopted throughout the compiler and standard libraries to comply
with this modification of the lint.
Travis CI provides an easy-to-use continuous integration infrastructure for
github repos to use. Travis will automatically test all PRs which are opened
against the rust repository, informing PR owners of the test results.
I believe that this will be a very convenient piece of infrastructure as we'll
be able to reduce the load on bors quite a bit. In theory all PRs opened have
had the full test suite run against them, but unfortunately this is rarely the
case (I'm a prime suspect). Travis will be able to provide easy and relatively
quick (~30min) feedback for PRs. By ensuring fewer failures on bors, we can
hopefully feed more successful jobs to bors.
Overall, I expect this to be very helpful for new contributors as well as
regular contributors as it's another layer of tests being run which will
hopefully catch things sooner. One of the most convenient parts about using
Travis is that there's very little burden in terms of maintenance, and if things
go wrong we can easily turn travis completely off.
Note that this is *not* the metric by which a PR will be merged with. Using
travis will purely be another source for running tests, we will continue to gate
all PRs on bors.
This patch merges IterBytes and Hash traits, which clears up the
confusion of using `#[deriving(IterBytes)]` to support hashing.
Instead, it now is much easier to use the new `#[deriving(Hash)]`
for making a type hashable with a stream hash.
Furthermore, it supports custom non-stream-based hashers, such as
if a value's hash was cached in a database.
This does not yet replace the old IterBytes-hash with this new
version.
Previously an `unsafe` block created by the compiler (like those in the
formatting macros) would be "ignored" if surrounded by `unsafe`, that
is, the internal unsafety would be being legitimised by the external
block:
unsafe { println!("...") } =(expansion)=> unsafe { ... unsafe { ... } }
And the code in the inner block would be using the outer block, making
it considered used (and the inner one considered unused).
This patch forces the compiler to create a new unsafe context for
compiler generated blocks, so that their internal unsafety doesn't
escape to external blocks.
Fixes#12418.
Added allow(non_camel_case_types) to librustc where necesary
Tried to fix problems with non_camel_case_types outside rustc
fixed failing tests
Docs updated
Moved #[allow(non_camel_case_types)] a level higher.
markdown.rs reverted
Fixed timer that was failing tests
Fixed another timer
Travis CI provides an easy-to-use continuous integration infrastructure for
github repos to use. Travis will automatically test all PRs which are opened
against the rust repository, informing PR owners of the test results.
I believe that this will be a very convenient piece of infrastructure as we'll
be able to reduce the load on bors quite a bit. In theory all PRs opened have
had the full test suite run against them, but unfortunately this is rarely the
case (I'm a prime suspect). Travis will be able to provide easy and relatively
quick (~30min) feedback for PRs. By ensuring fewer failures on bors, we can
hopefully feed more successful jobs to bors.
Overall, I expect this to be very helpful for new contributors as well as
regular contributors as it's another layer of tests being run which will
hopefully catch things sooner. One of the most convenient parts about using
Travis is that there's very little burden in terms of maintenance, and if things
go wrong we can easily turn travis completely off.
Note that this is *not* the metric by which a PR will be merged with. Using
travis will purely be another source for running tests, we will continue to gate
all PRs on bors.
This commit rewrites crate loading internally in attempt to look at less
metadata and provide nicer errors. The loading is now split up into a few
stages:
1. Collect a mapping of (hash => ~[Path]) for a set of candidate libraries for a
given search. The hash is the hash in the filename and the Path is the
location of the library in question. All candidates are filtered based on
their prefix/suffix (dylib/rlib appropriate) and then the hash/version are
split up and are compared (if necessary).
This means that if you're looking for an exact hash of library you don't have
to open up the metadata of all libraries named the same, but also in your
path.
2. Once this mapping is constructed, each (hash, ~[Path]) pair is filtered down
to just a Path. This is necessary because the same rlib could show up twice
in the path in multiple locations. Right now the filenames are based on just
the crate id, so this could be indicative of multiple version of a crate
during one crate_id lifetime in the path. If multiple duplicate crates are
found, an error is generated.
3. Now that we have a mapping of (hash => Path), we error on multiple versions
saying that multiple versions were found. Only if there's one (hash => Path)
pair do we actually return that Path and its metadata.
With this restructuring, it restructures code so errors which were assertions
previously are now first-class errors. Additionally, this should read much less
metadata with lots of crates of the same name or same version in a path.
Closes#11908
The new methodology can be found in the re-worded comment, but the gist of it is
that -C prefer-dynamic doesn't turn off static linkage. The error messages
should also be a little more sane now.
Closes#12133
Previously an `unsafe` block created by the compiler (like those in the
formatting macros) would be "ignored" if surrounded by `unsafe`, that
is, the internal unsafety would be being legitimised by the external
block:
unsafe { println!("...") } =(expansion)=> unsafe { ... unsafe { ... } }
And the code in the inner block would be using the outer block, making
it considered used (and the inner one considered unused).
This patch forces the compiler to create a new unsafe context for
compiler generated blocks, so that their internal unsafety doesn't
escape to external blocks.
Fixes#12418.
The new methodology can be found in the re-worded comment, but the gist of it is
that -C prefer-dynamic doesn't turn off static linkage. The error messages
should also be a little more sane now.
Closes#12133
Closes#11692. Instead of returning the original expression, a dummy expression
(with identical span) is returned. This prevents infinite loops of failed
expansions as well as odd double error messages in certain situations.
This is a slightly better fix than #12197, because it does not produce a double error and also fixes a few other cases where an infinite loop could happen.
This does not fix the other issue in #11692 (non-builtin macros not being recognised when expanded inside macros), which I think should be moved into a separate issue.
With Rc no longer trying to statically prevent cycles (and thus no
longer using the Freeze bound), it seems appropriate to remove that
restriction from MutexArc as well.
Closes#9251.
Closes#11692. Instead of returning the original expression, a dummy expression
(with identical span) is returned. This prevents infinite loops of failed
expansions as well as odd double error messages in certain situations.
This patch gets rid of ObsoleteExternModAttributesInParens and
ObsoleteNamedExternModule since the replacement of `extern mod` with
`extern crate` avoids those cases and raises different errors. Both have
been around for at least a version which makes this a good moment to get
rid of them.
This patch adds a new keyword `crate` which is intended to replace mod
in the context of `extern mod` as part of the issue #9880. The patch
doesn't replace all `extern mod` cases since it is necessary to first
push a new snapshot 0.
The implementation could've been less invasive than this. However I
preferred to take this chance to split the `parse_item_foreign_mod`
method and pull the `extern crate` part out of there, hence the new
method `parse_item_foreign_crate`.
While working on #11363 I stumbled over a couple of ignored tests, that seem to be fixed or invalid.
* src/test/run-pass/issue-3559.rs was fixed in #4726
* src/test/compile-fail/borrowck-call-sendfn.rs was fixed in #2978
* update src/test/compile-fail/issue-5500-1.rs to work with current Rust (I'm not 100% sure if the original condition is tested as mentioned in #5500, but I think so)
* removed src/test/compile-fail/issue-5500.rs because it is tested in
src/test/run-fail/issue-5500.rs (they are the same test cases, I just renamed src/test/run-fail/addr-of-bot.rs to be consistent with the other issue name
* src/test/run-pass/issue-3559.rs was fixed in #4726
* src/test/compile-fail/borrowck-call-sendfn.rs was fixed in #2978
* update src/test/compile-fail/issue-5500-1.rs to work with current Rust
* removed src/test/compile-fail/issue-5500.rs because it is tested in
src/test/run-fail/issue-5500.rs
* src/test/compile-fail/view-items-at-top.rs fixed
* #897 fixed
* compile-fail/issue-6762.rs issue was closed as dup of #6801
* deleted compile-fail/issue-2074.rs because it became irelevant and is
irrelevant #2074, a test covering this was added in
4f92f452bd
Loadable syntax extensions don't work when cross compiling (see #12102), so the
fourcc tests all need to be ignored. They're valuable tests, so they shouldn't
be outright ignored, so they're now flagged with ignore-cross-compile
This, the Nth rewrite of channels, is not a rewrite of the core logic behind
channels, but rather their API usage. In the past, we had the distinction
between oneshot, stream, and shared channels, but the most recent rewrite
dropped oneshots in favor of streams and shared channels.
This distinction of stream vs shared has shown that it's not quite what we'd
like either, and this moves the `std::comm` module in the direction of "one
channel to rule them all". There now remains only one Chan and one Port.
This new channel is actually a hybrid oneshot/stream/shared channel under the
hood in order to optimize for the use cases in question. Additionally, this also
reduces the cognitive burden of having to choose between a Chan or a SharedChan
in an API.
My simple benchmarks show no reduction in efficiency over the existing channels
today, and a 3x improvement in the oneshot case. I sadly don't have a
pre-last-rewrite compiler to test out the old old oneshots, but I would imagine
that the performance is comparable, but slightly slower (due to atomic reference
counting).
This commit also brings the bonus bugfix to channels that the pending queue of
messages are all dropped when a Port disappears rather then when both the Port
and the Chan disappear.
Loadable syntax extensions don't work when cross compiling (see #12102), so the
fourcc tests all need to be ignored. They're valuable tests, so they shouldn't
be outright ignored, so they're now flagged with ignore-cross-compile
This resolves issue #12157. Does that do it already or is there something else that needs taking care of?
As a side note, there seems to be some documentation, in which the old existence of the do keyword is explained. The list of keywords is not up-to-date either. But these are certainly separate issues.
Resolves issue #12157. `do` is hereby reinstated as a keyword; no syntax is
associated with it though. Along the way, a unit test had to be adapted, since
it was using `do` as a method identifier.
Breaking changes:
- Any code using `do` as an identifier will no longer work.
The previous definition was actually describing covariance.
Fixing to describe contravariance while keeping 'static in the definition was tricky so just changed to use 'short and 'long.
Repair a rather embarassingly obvious hole that I created as part of #9629. In particular, prevent `&mut` borrows of data in an aliasable location. This used to be prevented through the restrictions mechanism, but in #9629 I modified those rules incorrectly.
r? @pcwalton
Fixes#11913
fourcc!() allows you to embed FourCC (or OSType) values that are
evaluated as u32 literals. It takes a 4-byte ASCII string and produces
the u32 resulting in interpreting those 4 bytes as a u32, using either
the platform-native endianness, or explicitly as big or little endian.
Error messages cleaned in librustc/middle
Error messages cleaned in libsyntax
Error messages cleaned in libsyntax more agressively
Error messages cleaned in librustc more aggressively
Fixed affected tests
Fixed other failing tests
Last failing tests fixed
This removes @[] from the parser as well as much of the handling of it (and `@str`) from the compiler as I can find.
I've just rebased @pcwalton's (already reviewed) `@str` removal (and fixed the problems in a separate commit); the only new work is the trailing commits with my authorship.
Closes#11967
This is has been obsolete for quite a while now (including a release),
so removing the special handling seems fine. (The error message is quite
good still anyway.)
Fixes#9580.
It was possible to trigger a stack overflow in rustc because the routine used to verify enum representability,
type_structurally_contains, would recurse on inner types until hitting the original type. The overflow condition was when a different structurally recursive type (enum or struct) was contained in the type being checked.
I suspect my solution isn't as efficient as it could be. I pondered adding a cache of previously-seen types to avoid duplicating work (if enums A and B both contain type C, my code goes through C twice), but I didn't want to do anything that may not be necessary.
I'm a new contributor, so please pay particular attention to any unidiomatic code, misuse of terminology, bad naming of tests, or similar horribleness :)
Updated to verify struct representability as well.
Fixes#3008.
Fixes#3779.
`Times::times` was always a second-class loop because it did not support the `break` and `continue` operations. Its playful appeal (which I liked) was then lost after `do` was disabled for closures. It's time to let this one go.
`Times::times` was always a second-class loop because it did not support the `break` and `continue` operations. Its playful appeal was then lost after `do` was disabled for closures. It's time to let this one go.
The general consensus is that we want to move away from conditions for I/O, and I propose a two-step plan for doing so:
1. Warn about unused `Result` types. When all of I/O returns `Result`, it will require you inspect the return value for an error *only if* you have a result you want to look at. By default, for things like `write` returning `Result<(), Error>`, these will all go silently ignored. This lint will prevent blind ignorance of these return values, letting you know that there's something you should do about them.
2. Implement a `try!` macro:
```
macro_rules! try( ($e:expr) => (match $e { Ok(e) => e, Err(e) => return Err(e) }) )
```
With these two tools combined, I feel that we get almost all the benefits of conditions. The first step (the lint) is a sanity check that you're not ignoring return values at callsites. The second step is to provide a convenience method of returning early out of a sequence of computations. After thinking about this for awhile, I don't think that we need the so-called "do-notation" in the compiler itself because I think it's just *too* specialized. Additionally, the `try!` macro is super lightweight, easy to understand, and works almost everywhere. As soon as you want to do something more fancy, my answer is "use match".
Basically, with these two tools in action, I would be comfortable removing conditions. What do others think about this strategy?
----
This PR specifically implements the `unused_result` lint. I actually added two lints, `unused_result` and `unused_must_use`, and the first commit has the rationale for why `unused_result` is turned off by default.
I attempted to implement the lint in two steps. My first attempt was a
default-warn lint about *all* unused results. While this attempt did indeed find
many possible bugs, I felt that the false-positive rate was too high to be
turned on by default for all of Rust.
My second attempt was to make unused-result a default-allow lint, but allow
certain types to opt-in to the notion of "you must use this". For example, the
Result type is now flagged with #[must_use]. This lint about "must use" types is
warn by default (it's different from unused-result).
The unused_must_use lint had a 100% hit rate in the compiler, but there's not
that many places that return Result right now. I believe that this lint is a
crucial step towards moving away from conditions for I/O (because all I/O will
return Result by default). I'm worried that this lint is a little too specific
to Result itself, but I believe that the false positive rate for the
unused_result lint is too high to make it useful when turned on by default.
cc #7621.
See the commit message. I'm not sure if we should merge this now, or wait until we can write `Clone::clone(x)` which will directly solve the above issue with perfect error messages.
