explicit form `Fn<A,B>` and now should use `Fn(A) -> B` or
`Fn<A,Output=B>`, but in some cases we get duplicate error
reports. This is mildly annoying and arises because of the main error
and another error from the projection. Might be worth squashing those,
but seems like a separate problem.
This implements the remaining bits of 'feature staging', as described in [RFC 507](https://github.com/rust-lang/rfcs/blob/master/text/0507-release-channels.md).
This is not quite done, but the substance of the work is complete so submitting for early review.
Key changes:
* `unstable`, `stable` and `deprecated` attributes all require 'feature' and 'since', and support an optional 'reason'.
* The `unstable` lint is removed.
* A new 'stability checking' pass warns when a used unstable library feature has not been activated with the `feature` attribute. At 1.0 beta this will become an error.
* A new 'unused feature checking' pass emits a lint ('unused_feature', renamed from 'unknown_feature') for any features that were activated but not used.
* A new tidy script `featureck.py` performs some global sanity checking, particularly that 'since' numbers agree, and also prints out a summary of features.
Differences from RFC:
* As implemented `unstable` requires a `since` attribute. I do not know if this is useful. I included it in the original sed script and just left it.
* RFC didn't specify the name of the optional 'reason' attribute.
* This continues to use 'unstable', 'stable' and 'deprecated' names (the 'nice' names) instead of 'staged_unstable', but only activates them with the crate-level 'staged_api' attribute.
I intend to update the RFC based on the outcome of this PR.
Issues:
* The unused feature check doesn't account for language features - i.e. you can activate a language feature, not use it, and not get the error.
Open questions:
* All unstable and deprecated features are named 'unnamed_feature', which i picked just because it is uniquely greppable. This is the 'catch-all' feature. What should it be?
* All stable features are named 'grandfathered'. What should this be?
TODO:
* Add check that all `deprecated` attributes are paired with a `stable` attribute in order to preserve the knowledge about when a feature became stable.
* Update rustdoc in various ways.
* Remove obsolete stability discussion from reference.
* Add features for 'path', 'io', 'os', 'hash' and 'rand'.
cc #20445 @alexcrichton @aturon
UFCS form. In both cases the problems came about because we were
failing to process pending trait obligations. So change code to
process pending trait obligations before coercions to ensure maximum
type information is available (and also adjust shift to do something
similar).
Fixes#21245.
In preparation for upcoming changes to the `Writer` trait (soon to be called
`Write`) this commit renames the current `write` method to `write_all` to match
the semantics of the upcoming `write_all` method. The `write` method will be
repurposed to return a `usize` indicating how much data was written which
differs from the current `write` semantics. In order to head off as much
unintended breakage as possible, the method is being deprecated now in favor of
a new name.
[breaking-change]
As part of #20432, upvar checking is now moved out of regionck to its
own pass and before regionck. But regionck has some type resolution of
its own. Without them, now separated upvar checking may be tripped over
by residue `ty_infer`.
Closes#21306
Fix for `error: functions used as tests must have signature fn() -> ()` and `error: functions used as benches must have signature `fn(&mut Bencher) -> ()` in case of explicit return type declaration.
While trying to experiment with changes for some other issues, I noticed that the test for #15149 was failing because I have `/tmp` mounted as `noexec` on my Linux box, and that test tries to run out of a temporary directory. This may not be the most common case, but it's not rare by any means, because executing from a world-writable directory is a security problem. (For this reason, some kernel options/mods such as grsecurity also can prevent this on Linux.) I instead copy the executable to a directory created in the build tree, following the example of the `process-spawn-with-unicode-params` test.
After I made that change, I noticed that I'd made a mistake, but the test was still passing, because the "parent" process was not actually checking the status of the "child" process, meaning that the assertion in the child could never cause the overall test to fail. (I don't know if this has always been the case, or if it has something to do with either Windows or a change in the semantics of `spawn`.) So I fixed the test so that it would fail correctly, then fixed my original mistake so that it would pass again.
The one big problem with this is that I haven't set up any machines of my own so that I can build on Windows, which is the platform this test was targeted at in the first place! That might take a while to address on my end. So I need someone else to check this on Windows.
The regex library was largely used for non-critical aspects of the compiler and
various external tooling. The library at this point is duplicated with its
out-of-tree counterpart and as such imposes a bit of a maintenance overhead as
well as compile time hit for the compiler itself.
The last major user of the regex library is the libtest library, using regexes
for filters when running tests. This removal means that the filtering has gone
back to substring matching rather than using regexes.
As part of #20432, upvar checking is now moved out of regionck to its
own pass and before regionck. But regionck has some type resolution of
its own. Without them, now separated upvar checking may be tripped over
by residue `ty_infer`.
Closes#21306
Grammar changes:
* allow 'for _ in 1..i {}' (fixes#20241)
* allow 'for _ in 1.. {}' as infinite loop
* prevent use of range notation in contexts where only operators of high
precedence are expected (fixes#20811)
Parser code cleanup:
* remove RESTRICTION_NO_DOTS
* make AS_PREC const and follow naming convention
* make min_prec inclusive
This is a bit of cleanup work to clean out some old deprecated flags and deprecated lint names from the compiler (they've been deprecated for quite awhile now).
This also notably puts `--pretty` behind the `-Z unstable-options` flag (where it was supposed to be previously).
closes#20953closes#21361
---
In the future, we will likely derive these `impl`s via syntax extensions or using compiler magic (see #20617). For the time being we can use these manual `impl`s.
r? @aturon
cc @burntsushi @Kroisse
There are two limitations to the macro that this addresses:
1. the expected type is not propagated, coercions don't trigger
2. references inside element expressions don't outlive the `Vec`
Both of these limitations are caused by the block in the
macro expansion, previously needed to trigger a coercion
from `Box<[T; N]>` to `Box<[T]>`, now possible with UFCS.
This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md
* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
RFC and audited implementations now have the `#[stable]` attribute
* Integers and floats no longer print a suffix
* Smart pointers no longer print details that they are a smart pointer
* Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
`Display` must be implemented. With the loss of `String`, this has moved into
libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
warned about due to warnings being emitted on stage1+
While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.
[breaking-change]
Closes#21436
