This flag indicates that when files are being replaced or added to archives (the
`r` flag) that the new file should not be inserted if it is not newer than the
file that already exists in the archive. The compiler never actually has a use
case of *not* wanting to insert a file because it already exists, and this
causes rlibs to not be updated in some cases when the compiler was re-run too
quickly.
Closes#18913
The caching essentially eliminates "stability checking" time (my attempt to clean-up junk got tangled up with stability, so I added the caching while I was at it).
r? @eddyb
A regression was introduced by commit 7b1916d253#25612. Negative signed integer literals less than -9223372036854775808i64 were no longer properly reported as #[warn(overflowing_literals)].
Also adding missing test cases to test/compile-fail/lint-type-overflow.rs which could have detected the regression.
Further explanation:
The expression `(negative && v > max as u64 + 1)` relies on the fact that algebraically speaking `-min == max + 1` to avoid negation and removing the need for `min` completely.
If i128 or i256 are ever added, it should also work for these types without requiring a change to `min != i64::MIN &&` also simplifying maintenance.
r? @pnkfelix
Currently, for `use` declarations with multiple paths, only the `use`
item itself is saved in the AST map, not the individual path nodes. This
can lead to a problem when a span of a specific path node is needed.
For example, #24818 caused an ICE because of this, in
`ImportResolver::check_for_conflicting_import()`.
Fixes#25763.
In all other places the IDs of link references are without spaces (and explicitly set).
These are just some cleanups I did for the PDF version.
r? @steveklabnik
I'm not sure why `core` is on but it's blocking the playpen. Doesn't seem to be needed but I'm not sure. It's not on the playpen template and playpen works on release and nightly.
Seems easier to understand without `take()`.
A few of us [over on the forum](https://users.rust-lang.org/t/string-type-coercion-in-rust/1439) have been tripped up by this distinction, which I don't think is mentioned. It's kind of logical if you read the "Deref coercions" page and squint a bit but I think it would be nice to explain it directly. Here's one way we could clarify it.
Functions such as `fn foo<I: Iterator>(x: I::Item)` would not
render correctly and displayed `I` instead of `I::Item`. Same thing
with `I::Item` appearing in where bounds.
This fixes the bug by using paths for generics.
Fixes#24417
Typo in explanation of difference between stack and heap values.
`baz` is called at the end of a call to `bar` inside another call to `foo`. `baz` takes a copy of the value `e` which should have a value of 9 if following the rest of the stack trace.
This PR fixes this typo and should close#25635.
This is a port of @eddyb's `const-fn` branch. I rebased it, tweaked a few things, and added tests as well as a feature gate. The set of tests is still pretty rudimentary, I'd appreciate suggestions on new tests to write. Also, a double-check that the feature-gate covers all necessary cases.
One question: currently, the feature-gate allows the *use* of const functions from stable code, just not the definition. This seems to fit our usual strategy, and implies that we might (perhaps) allow some constant functions in libstd someday, even before stabilizing const-fn, if we were willing to commit to the existence of const fns but found some details of their impl unsatisfactory.
r? @pnkfelix
`core::cell::Cell<T>` and `core::cell::RefCell<T>` currently implement
`PartialEq` when `T` does, and just defer to comparing `T` values.
There is no reason the same shouldn’t apply to `Eq`.
This enables `#[derive(Eq, PartialEq)]` on e.g.
structs that have a `RefCell` field.
The first one in particular results in Rust not being able to build itself
if it is installed. The latter two shouldn't be necessary, and should only
be included if they are actually going to be used.
fixes#25683
I have a very nonscientific measurement of the data via valgrind/massif [here](https://gist.github.com/Manishearth/4c47f15f6835cb3957c4)
I measured the memory usage for both --pretty=expanded and -Z no-trans
It *seems* like there's a 20-25MB decrease during expansion on stage2 librustc; but I'm not quite sure.
r? @eddyb
(have not yet run tests, but it compiles fine, might want to wait before giving r+)
cc @nrc @huon
Reduces pre-trans heap baseline (tested on `fn main() {}`) from 1.2MB to 696kB.
Most of the remaining allocations are used by imported macros.
While it might be possible to also load macros lazily, doing so is non-trivial and this PR doesn't tackle that.
This minimally changes rustdoc's search as described in #25167.
Additionally, I also cleaned up some parts of the JS code.
There is one more change I made: After each result for a primitive type, I added "(Overview of primitive type)". This further differentiates the result from the module (previously, the only difference was that the module's link was blue). I'm not this is the way to go (this seems to be the only place where we do this) and it's no problem for me to remove that commit.
cc @steveklabnik (it concerns docs) and @alexcrichton (who made changes to rustdoc previously)
The change to split up soft_link to OS-specific symlink, symlink_file,
and symlink_dir didn't actually land in 1.0.0. Update the stability and
deprecation attributes to correctly indicate that these changes happend
in 1.1.0.
This "fast path" in `DirEntry::file_type` on Unix wasn't turning out to be so
much of a fast path as the `DT_DIR` case wasn't handled, so directories fell
back to using `lstat` instead. This commit adds the missing case to return
quickly if a path is a directory and `DirEntry::file_type` is used.
This was motivated by http://www.evanmiller.org/a-taste-of-rust.html.
A common problem when working with FFI right now is converting from raw
C strings into `&str` or `String`. Right now you're required to say
something like
let cstr = unsafe { CStr::from_ptr(ptr) };
let result = str::from_utf8(cstr.to_bytes());
This is slightly awkward, and is not particularly intuitive for people
who haven't used the ffi module before. We can do a bit better by
providing some convenience methods on CStr:
fn to_str(&self) -> Result<&str, str::Utf8Error>
fn to_string_lossy(&self) -> Cow<str>
This will make it immediately apparent to new users of CStr how to get a
string from a raw C string, so they can say:
let s = unsafe { CStr::from_ptr(ptr).to_string_lossy() };
The `debug_builders` feature is up for 1.1 stabilization in #24028. This commit stabilizes the API as-is with no changes.
Some nits that @alexcrichton mentioned that may be worth discussing now if anyone cares:
* Should `debug_tuple_struct` and `DebugTupleStruct` be used instead of `debug_tuple` and `DebugTuple`? It's more typing but is a technically more correct name.
* `DebugStruct` and `DebugTuple` have `field` methods while `DebugSet`, `DebugMap` and `DebugList` have `entry` methods. Should we switch those to something else for consistency?
cc @alexcrichton @aturon
A common problem when working with FFI right now is converting from raw
C strings into `&str` or `String`. Right now you're required to say
something like
let cstr = unsafe { CStr::from_ptr(ptr) };
let result = str::from_utf8(cstr.to_bytes());
This is slightly awkward, and is not particularly intuitive for people
who haven't used the ffi module before. We can do a bit better by
providing some convenience methods on CStr:
fn to_str(&self) -> Result<&str, str::Utf8Error>
fn to_string_lossy(&self) -> Cow<str>
This will make it immediately apparent to new users of CStr how to get a
string from a raw C string, so they can say:
let s = unsafe { CStr::from_ptr(ptr).to_string_lossy() };
There are more possible optimizations left (cached length in loops) as
well as some possible bugs (shadowed variables) to fix. This is mostly
syntactic.
- add feature gate
- add basic tests
- adjust parser to eliminate conflict between `const fn` and associated
constants
- allow `const fn` in traits/trait-impls, but forbid later in type check
- correct some merge conflicts
For a trait *implementation* there are typedefs which are the types for
that particular trait and implementor. Skip these in the search index.
There were lots of dud items in the search index due to this (search for
Item, Iterator's associated type).
Add a boolean to clean::TypedefItem so that it tracks whether the it is
a type alias on its own, or if it's a `type` item in a trait impl.
Fixes#22442
The change to split up soft_link to OS-specific symlink, symlink_file,
and symlink_dir didn't actually land in 1.0.0. Update the stability and
deprecation attributes to correctly indicate that these changes happend
in 1.1.0.
collections: Reorder slice methods to improve API docs
We have an evolutionary history whose traces are still visible in the
slice docs today.
Some heuristics:
* Group method and method_mut together
* Group method and method_by together
* Group by use case, here we have roughly:
Basic interrogators (len)
Mutation (swap)
Iterators (iter)
Segmentation (split)
Searching (contains)
Permutations (permutations)
Misc (clone_from_slice)
It is hard to find the actual unstable feature which caused the error when using a list of stable and unstable features as the span marks the whole line
```
src/k8055.rs:22:1: 22:64 error: unstable feature
src/k8055.rs:22 #![feature(slice_patterns, rustc_private, core, convert, libc)]
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
This PR spawns an error for each unstable feature in the list:
```
est.rs:1:12: 1:26 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
^~~~~~~~~~~~~~
test.rs:1:28: 1:41 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
^~~~~~~~~~~~~
test.rs:1:43: 1:47 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
^~~~
test.rs:1:49: 1:56 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
^~~~~~~
test.rs:1:58: 1:62 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
^~~~
```
We have an evolutionary history whose traces are still visible in the
slice docs today.
Some heuristics:
* Group method and method_mut together
* Group method and method_by together
* Group by use case, here we have roughly:
Basic interrogators (len)
Mutation (swap)
Iterators (iter)
Segmentation (split)
Searching (contains)
Permutations (permutations)
Misc (clone_from_slice)
When taking the address of an unsized field we generate a rvalue datum
for the field and then convert it to an lvalue datum. At that point,
cleanup is scheduled for the field, leading to multiple drop calls.
The problem is that we generate an rvalue datum for the field, since the
pointer does not own the data and there's already cleanup scheduled
elsewhere by the true owner. Instead, an lvalue datum must be created.
Thanks to @eddyb for identifying the underlying cause and suggesting the
correct fix.
Fixes#25549.
Use stable code in doc examples (libcollections)
Main task is to change from String::from_str to String::from in examples for String
(the latter constructor is stable). While I'm at it, also remove redundant feature flags,
fix some other instances of unstable code in examples (in examples for stable
methods), and remove some use of usize in examples too.
This "fast path" in `DirEntry::file_type` on Unix wasn't turning out to be so
much of a fast path as the `DT_DIR` case wasn't handled, so directories fell
back to using `lstat` instead. This commit adds the missing case to return
quickly if a path is a directory and `DirEntry::file_type` is used.
Special thanks to @retep998 for the [excellent writeup](https://github.com/rust-lang/rfcs/issues/1061) of tasks to be done and @ricky26 for initially blazing the trail here!
# MSVC Support
This goal of this series of commits is to add MSVC support to the Rust compiler
and build system, allowing it more easily interoperate with Visual Studio
installations and native libraries compiled outside of MinGW.
The tl;dr; of this change is that there is a new target of the compiler,
`x86_64-pc-windows-msvc`, which will not interact with the MinGW toolchain at
all and will instead use `link.exe` to assemble output artifacts.
## Why try to use MSVC?
With today's Rust distribution, when you install a compiler on Windows you also
install `gcc.exe` and a number of supporting libraries by default (this can be
opted out of). This allows installations to remain independent of MinGW
installations, but it still generally requires native code to be linked with
MinGW instead of MSVC. Some more background can also be found in #1768 about the
incompatibilities between MinGW and MSVC.
Overall the current installation strategy is quite nice so long as you don't
interact with native code, but once you do the usage of a MinGW-based `gcc.exe`
starts to get quite painful.
Relying on a nonstandard Windows toolchain has also been a long-standing "code
smell" of Rust and has been slated for remedy for quite some time now. Using a
standard toolchain is a great motivational factor for improving the
interoperability of Rust code with the native system.
## What does it mean to use MSVC?
"Using MSVC" can be a bit of a nebulous concept, but this PR defines it as:
* The build system for Rust will build as much code as possible with the MSVC
compiler, `cl.exe`.
* The build system will use native MSVC tools for managing archives.
* The compiler will link all output with `link.exe` instead of `gcc.exe`.
None of these are currently implemented today, but all are required for the
compiler to fluently interoperate with MSVC.
## How does this all work?
At the highest level, this PR adds a new target triple to the Rust compiler:
x86_64-pc-windows-msvc
All logic for using MSVC or not is scoped within this triple and code can
conditionally build for MSVC or MinGW via:
#[cfg(target_env = "msvc")]
It is expected that auto builders will be set up for MSVC-based compiles in
addition to the existing MinGW-based compiles, and we will likely soon start
shipping MSVC nightlies where `x86_64-pc-windows-msvc` is the host target triple
of the compiler.
# Summary of changes
Here I'll explain at a high level what many of the changes made were targeted
at, but many more details can be found in the commits themselves. Many thanks to
@retep998 for the excellent writeup in rust-lang/rfcs#1061 and @rick26 for a lot
of the initial proof-of-concept work!
## Build system changes
As is probably expected, a large chunk of this PR is changes to Rust's build
system to build with MSVC. At a high level **it is an explicit non goal** to
enable building outside of a MinGW shell, instead all Makefile infrastructure we
have today is retrofitted with support to use MSVC instead of the standard MSVC
toolchain. Some of the high-level changes are:
* The configure script now detects when MSVC is being targeted and adds a number
of additional requirements about the build environment:
* The `--msvc-root` option must be specified or `cl.exe` must be in PATH to
discover where MSVC is installed. The compiler in use is also required to
target x86_64.
* Once the MSVC root is known, the INCLUDE/LIB environment variables are
scraped so they can be reexported by the build system.
* CMake is required to build LLVM with MSVC (and LLVM is also configured with
CMake instead of the normal configure script).
* jemalloc is currently unconditionally disabled for MSVC targets as jemalloc
isn't a hard requirement and I don't know how to build it with MSVC.
* Invocations of a C and/or C++ compiler are now abstracted behind macros to
appropriately call the underlying compiler with the correct format of
arguments, for example there is now a macro for "assemble an archive from
objects" instead of hard-coded invocations of `$(AR) crus liboutput.a ...`
* The output filenames for standard libraries such as morestack/compiler-rt are
now "more correct" on windows as they are shipped as `foo.lib` instead of
`libfoo.a`.
* Rust targets can now depend on native tools provided by LLVM, and as you'll
see in the commits the entire MSVC target depends on `llvm-ar.exe`.
* Support for custom arbitrary makefile dependencies of Rust targets has been
added. The MSVC target for `rustc_llvm` currently requires a custom `.DEF`
file to be passed to the linker to get further linkages to complete.
## Compiler changes
The modifications made to the compiler have so far largely been minor tweaks
here and there, mostly just adding a layer of abstraction over whether MSVC or a
GNU-like linker is being used. At a high-level these changes are:
* The section name for metadata storage in dynamic libraries is called `.rustc`
for MSVC-based platorms as section names cannot contain more than 8
characters.
* The implementation of `rustc_back::Archive` was refactored, but the
functionality has remained the same.
* Targets can now specify the default `ar` utility to use, and for MSVC this
defaults to `llvm-ar.exe`
* The building of the linker command in `rustc_trans:🔙:link` has been
abstracted behind a trait for the same code path to be used between GNU and
MSVC linkers.
## Standard library changes
Only a few small changes were required to the stadnard library itself, and only
for minor differences between the C runtime of msvcrt.dll and MinGW's libc.a
* Some function names for floating point functions have leading underscores, and
some are not present at all.
* Linkage to the `advapi32` library for crypto-related functions is now
explicit.
* Some small bits of C code here and there were fixed for compatibility with
MSVC's cl.exe compiler.
# Future Work
This commit is not yet a 100% complete port to using MSVC as there are still
some key components missing as well as some unimplemented optimizations. This PR
is already getting large enough that I wanted to draw the line here, but here's
a list of what is not implemented in this PR, on purpose:
## Unwinding
The revision of our LLVM submodule [does not seem to implement][llvm] does not
support lowering SEH exception handling on the Windows MSVC targets, so
unwinding support is not currently implemented for the standard library (it's
lowered to an abort).
[llvm]: https://github.com/rust-lang/llvm/blob/rust-llvm-2015-02-19/lib/CodeGen/Passes.cpp#L454-L461
It looks like, however, that upstream LLVM has quite a bit more support for SEH
unwinding and landing pads than the current revision we have, so adding support
will likely just involve updating LLVM and then adding some shims of our own
here and there.
## dllimport and dllexport
An interesting part of Windows which MSVC forces our hand on (and apparently
MinGW didn't) is the usage of `dllimport` and `dllexport` attributes in LLVM IR
as well as native dependencies (in C these correspond to
`__declspec(dllimport)`).
Whenever a dynamic library is built by MSVC it must have its public interface
specified by functions tagged with `dllexport` or otherwise they're not
available to be linked against. This poses a few problems for the compiler, some
of which are somewhat fundamental, but this commit alters the compiler to attach
the `dllexport` attribute to all LLVM functions that are reachable (e.g. they're
already tagged with external linkage). This is suboptimal for a few reasons:
* If an object file will never be included in a dynamic library, there's no need
to attach the dllexport attribute. Most object files in Rust are not destined
to become part of a dll as binaries are statically linked by default.
* If the compiler is emitting both an rlib and a dylib, the same source object
file is currently used but with MSVC this may be less feasible. The compiler
may be able to get around this, but it may involve some invasive changes to
deal with this.
The flipside of this situation is that whenever you link to a dll and you import
a function from it, the import should be tagged with `dllimport`. At this time,
however, the compiler does not emit `dllimport` for any declarations other than
constants (where it is required), which is again suboptimal for even more
reasons!
* Calling a function imported from another dll without using `dllimport` causes
the linker/compiler to have extra overhead (one `jmp` instruction on x86) when
calling the function.
* The same object file may be used in different circumstances, so a function may
be imported from a dll if the object is linked into a dll, but it may be
just linked against if linked into an rlib.
* The compiler has no knowledge about whether native functions should be tagged
dllimport or not.
For now the compiler takes the perf hit (I do not have any numbers to this
effect) by marking very little as `dllimport` and praying the linker will take
care of everything. Fixing this problem will likely require adding a few
attributes to Rust itself (feature gated at the start) and then strongly
recommending static linkage on Windows! This may also involve shipping a
statically linked compiler on Windows instead of a dynamically linked compiler,
but these sorts of changes are pretty invasive and aren't part of this PR.
## CI integration
Thankfully we don't need to set up a new snapshot bot for the changes made here as our snapshots are freestanding already, we should be able to use the same snapshot to bootstrap both MinGW and MSVC compilers (once a new snapshot is made from these changes).
I plan on setting up a new suite of auto bots which are testing MSVC configurations for now as well, for now they'll just be bootstrapping and not running tests, but once unwinding is implemented they'll start running all tests as well and we'll eventually start gating on them as well.
---
I'd love as many eyes on this as we've got as this was one of my first interactions with MSVC and Visual Studio, so there may be glaring holes that I'm missing here and there!
cc @retep998, @ricky26, @vadimcn, @klutzy
r? @brson
"Truth passes, success `panic!`s" seems to be a typo. The closest fix would be something like "Success passes, failure `panic!`s" but to me a "comparison failure" suggests that we couldn't compare the two values at all, not that we could successfully compare them and that the result was non-equality. So I opted to rewrite the paragraph a bit. If there's a better alternative please let me know.
r? @steveklabnik
Padding and alignment are often not implemented by types and can cause confusion in the user. Per discussion with @alexcrichton, here is my PR.
/cc https://github.com/rust-lang/time/issues/98
The paper from which this example was taken made the mistake of assuming that all five philosophers are men. This it is a hypothetical example—there are no actual philosophers eating 🍝—so there is no good reason to make this assumption. Since women make up about half of the human population, all things being equal, women should represent about half of the philosophers. However, because this mistake has stood since 1985, I have changed *all* of the pronouns to be female, to make up for lost time. If someone would like to revert this patch or switch to neutral pronouns after 30 years, feel free to set your alarm clock for 2045.
r? @steveklabnik, since this is a documentation change and was created after reading http://words.steveklabnik.com/ouroboros, where I noticed this mistake.
The paper from which this example was taken made the mistake of assuming
that all five philosophers are men. This is a hypothetical
example--there are no actual philosophers eating spaghetti--so there is
no good reason to make this assumption. Since women make up about half
of the human population, all things being equal, women should represent
about half of the philosophers. However, because this mistake has stood
since 1985, I have changed *all* of the pronouns to be female, to make
up for lost time. If someone would like to revert this patch or switch
to neutral pronouns after 30 years, feel free to set your alarm clock
for 2045.
This commits adds a method to the `std::process` module to get the process
identifier of the child as a `u32`. On Windows the underlying identifier is
already a `u32`, and on Unix the type is typically defined as `c_int` (`i32` for
almost all our supported platforms), but the actually pid is normally a small
positive number.
Eventually we may add functions to load information about a process based on its
identifier or the ability to terminate a process based on its identifier, but
for now this function should enable this sort of functionality to exist outside
the standard library.
This commit adds a small non-generic non-inlineable shim function to
`rt::unwind::try` which the compiler can take care of for managing the exported
symbol instead of having to edit `src/rt/rust_try.ll`
This commit modifies the compiler to emit `dllexport` for all reachable
functions and data on MSVC targets, regardless of whether a dynamic library is
being created or not. More details can be found in the commit itself.
This function is imported across the DLL boundary by the libtest dynamic
library, so it has to be marked as dllexport somehow, and for now this is done
with an attribute on the function specifically.
At this time unwinding support is not implemented for MSVC as
`libgcc_s_seh-1.dll` is not available by default (and this is used on MinGW),
but this should be investigated soon. For now this change is just aimed at
getting the compiler far enough to bootstrap everything instead of successfully
running tests.
This commit refactors the `std::rt::unwind` module a bit to prepare for SEH
support eventually by moving all GCC-specific functionality to its own submodule
and defining the interface needed.
For imports of constants across DLLs to work on Windows it *requires* that the
import be marked with `dllimport` (unlike functions where the marker is
optional, but strongly recommended). This currently isn't working for importing
FFI constants across boundaries, however, so the one constant exported from
`rustc_llvm.dll` is now a function to be called instead.
Windows needs explicit exports of functions from DLLs but LLVM does not mention
any of its symbols as being export-able from a DLL. The compiler, however,
relies on being able to use LLVM symbols across DLL boundaries so we need to
force many of LLVM's symbols to be exported from `rustc_llvm.dll`. This commit
adds support for generation of a `rustc_llvm.def` file which is passed along to
the linker when generating `rustc_llvm.dll` which should keep all these symbols
exportable and usable.
This commit adds an implementation of the `Linker` trait which is used to drive
MSVC's `link.exe` support. Nothing too surprising here as it's mostly just
filling out the necessary tidbits here and there.
These libraries don't exist! The linker for MSVC is highly likely to not pass
`/NODEFAULTLIB` in which case the right standard library will automatically be
selected.
This commit was initially written to target either `ar` or `lib.exe` for MSVC,
but it ended up not needing `lib.exe` support after all. I would personally like
to refactor this to one day not invoke processes at all (but rather use the
`llvm-ar.cpp` file in LLVM as alibrary) so I chose to preserve this refactoring
to allow it to be easily done in the future.
It looks like section names in objects generated by `link.exe` are limited to at
most 8 characters in length, so shorten `.note.rustc` to just `.rustc`
* Detect the #define _MSC_VER in addition to __WIN32__
* Don't include valgrind.h for windows
* Remove unused `rust_valgrind_stack_{un,}register` functions
* Add stub definition for `rust_running_on_valgrind` for windows
* Conditionally define `rust_dbg_extern_empty_struct` as empty structures are
not allowed by cl.exe apparently.
I think I didn't run tests properly - my second call to
select_all_obligations_or_error has made 3 tests fail. However, this is
just an error message change - integer fallback never worked with casts.
This should hopefully fix all cast-related ICEs once and for all.
I managed to make diagnostics hate me and give me spurious "decoder error"
- removing $build/tmp/extended-errors seems to fix it.
This adds strictly more information to the source files and reduces the need for customized tooling to render the book. (While this should not change the output of _rustbook_, it is very useful when rendering the sources with external tools like Pandoc.)
This only adds the language marker to "first level" code blocks (and not to code blocks in comments inside of code examples).
r? @steveklabnik
Currently the table of contents for `rustbook` doesn't signify which page you are on.
This PR adds an 'active' class to the link for the current page, and defines the CSS rule for that class to make the link underlined and bold.
Not sure about two things:
1) Is `current_page` is a good name for the function parameter? At first I thought `current_item` would be good, but then in the `walk_item` function, you'd have `item` and `current_item`.
2) For the CSS, is both bold and underline too much? At first I had it just be underlined, but that's also how the links look when they're hovered over.
The source code snippet uses `"whatever".as_bytes()` but the compilation error message uses `b"whatever"`. Both should be consistent with each other.
r? @steveklabnik
Minor tweak: the text explaining the Borrow trait talks about slices, but the example immediately following just uses a simple reference; there are no slices involved.
r? @steveklabnik
When taking the address of an unsized field we generate a rvalue datum
for the field and then convert it to an lvalue datum. At that point,
cleanup is scheduled for the field, leading to multiple drop calls.
The problem is that we generate an rvalue datum for the field, since the
pointer does not own the data and there's already cleanup scheduled
elsewhere by the true owner. Instead, an lvalue datum must be created.
Thanks to @eddyb for identifying the underlying cause and suggesting the
correct fix.
Fixes#25549Fixes#25515
Prefer String::from over from_str; String::from_str is unstable while
String::from is stable. Promote the latter by using it in examples.
Simply migrating unstable function to the closest alternative.
Debug overflow checks for arithmetic negation landed in #24500, at which time
the `abs` method on signed integers was changed to using `wrapping_neg` to
ensure that the function never panicked. This implied that `abs` of `INT_MIN`
would return `INT_MIN`, another negative value. When this change was back-ported
to beta, however, in #24708, the `wrapping_neg` function had not yet been
backported, so the implementation was changed in #24785 to `!self + 1`. This
change had the unintended side effect of enabling debug overflow checks for the
`abs` function. Consequently, the current state of affairs is that the beta
branch checks for overflow in debug mode for `abs` and the nightly branch does
not.
This commit alters the behavior of nightly to have `abs` always check for
overflow in debug mode. This change is more consistent with the way the standard
library treats overflow as well, and it is also not a breaking change as it's
what the beta branch currently does (albeit if by accident).
cc #25378
Debug overflow checks for arithmetic negation landed in #24500, at which time
the `abs` method on signed integers was changed to using `wrapping_neg` to
ensure that the function never panicked. This implied that `abs` of `INT_MIN`
would return `INT_MIN`, another negative value. When this change was back-ported
to beta, however, in #24708, the `wrapping_neg` function had not yet been
backported, so the implementation was changed in #24785 to `!self + 1`. This
change had the unintended side effect of enabling debug overflow checks for the
`abs` function. Consequently, the current state of affairs is that the beta
branch checks for overflow in debug mode for `abs` and the nightly branch does
not.
This commit alters the behavior of nightly to have `abs` always check for
overflow in debug mode. This change is more consistent with the way the standard
library treats overflow as well, and it is also not a breaking change as it's
what the beta branch currently does (albeit if by accident).
cc #25378
* Correctly lex CRLF in string literals
* Update `extern CRATE as NAME` syntax
* Allow leading `::` in view paths
* Allow TySums in type ascriptions and impls
* Allow macros to have visibility and attributes
* Update syntax for qualified path types and expressions
* Allow block expressions to be called () and indexed []
Some modest running-time improvements to `std::collections::BitSet` on bit-sets of varying set-membership densities. This is work originally from [here](https://github.com/rayglover/alt_collections). (Benchmarks copied below)
```
std::collections::BitSet / alt_collections::BitSet
copy_dense ... 3.08x
copy_sparse ... 4.22x
count_dense ... 11.01x
count_sparse ... 8.11x
from_bytes ... 1.47x
intersect_dense ... 6.54x
intersect_sparse ... 4.37x
union_dense ... 5.53x
union_sparse ... 5.60x
```
The exception is `from_bytes`, which I've left unaltered since the optimization is rather obscure.
Compiling with the cpu feature `popcnt` gave a further ~10% improvement on my machine, but this wasn't factored in to the benchmarks above.
Similar improvements could be made to `BitVec`, although that would probably require more substantial changes.
criticism welcome!
This adds strictly more information to the source files and reduces the
need for customized tooling to render the book.
(While this should not change the output of _rustbook_, it is very
useful when rendering the sources with external tools like Pandoc.)
Hiiii soooo I'm trying to get the reference grammar and associated tests running again, and I swear I tested before but I must have had multiple things going on when I did, because the change I made in #25137 to verify.rs is totally wrong. The RustLexer.tokens file that antlr generates has two sections:
```
EQ=1
LT=2
LE=3
EQEQ=4
NE=5
...
COMMENT=56
SHEBANG=57
UTF8_BOM=58
'='=1
'<'=2
'<='=3
'=='=4
...
```
and verify.rs is only interested in the first half-- the `continue` is to ignore the second half. In 9c7d5ae, I made it panic instead. I was trying to make sure verify.rs handled everything that might happen in the first half and complain if it didn't. That would mean the reference grammar was out of sync with at least verify.rs, if not the real grammar. But it's totally ok for verify.rs to not handle the entire second half of the file.
I'm sorry for breaking this :( Good thing these tests aren't being run regularly yet...? 😳
Tiny fixes collected while reading through the Rust book. If they're too nitpicky please let me know and I'll ignore the next ones. :)
The spaces after the function and closure arguments might be intentional, but they do not make much sense: the usual formatting doesn't have such spaces, and they aren't helping align the three lines together either.
r? @steveklabnik (as suggested by [CONTRIBUTING.md](https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md))
Fixes#23968.
Since the values are stored in a u64 internally, we need to be mask away the
high bits after applying the ! operator. Otherwise, these bits will be set to
one, causing overflow.
A built-in feature enabling the dereferencing of newtype structs was removed
in PR https://github.com/rust-lang/rust/pull/11188, and this error (E0068) was added at the same time to warn of
its removal. It seems to make sense to remove the error now, given that
the obsolete feature it is warning about was removed nearly a year and a
half ago.
Constants with values that depend on generic parameters or `Self` cause
ICEs in `check_const`, and are not yet accepted via RFC, so we need to
throw a proper error in these cases.
This reverts commit 9c7d5ae57c.
This was wrong... the `continue` was to ignore the latter half of the
tokens file. Another mechanism will have to be used to keep the model
grammar's tokens in sync with the actual grammar's tokens :-/
Since the values are stored in a u64 internally, we need to be mask away the
high bits after applying the ! operator. Otherwise, these bits will be set to
one, causing overflow.
The current version of the example won't compile due to unstable features.
This is an attempt to fix that, at the cost of slightly more verbose code.
Using rust 1.0.0 (a59de37e9).
It might be obvious, but I'm not well versed with rust, so feedback is very welcome.
This PR fixes two little typos in the Dining Philosophers example.
Also, there are two style points that may have been oversights but may have been deliberate, so I'll just bring them up here:
1) In the last paragraph, you say
> You’ll notice we can introduce a new binding to `table` here, and it will shadow the old one. This is often used so that you don’t need to come up with two unique names.
You already said something similar to this in the Guessing Game, but maybe you intended for this example to be independent of that one.
2) In "Rust Inside Other Languages," you introduce the idea of the "global interpreter lock" and then refer to it as the GIL a few paragraphs later without explicitly stating that GIL == global interpreter lock. It's reasonable to expect readers to make the connection, but maybe that's not what you intended.
Excellent work on the examples! Congrats on 1.0!
r? @steveklabnik
A built-in feature enabling the dereferencing of newtype structs was removed
in PR #11188, and this error (E0068) was added at the same time to warn of
its removal. It seems to make sense to remove the error now, given that
the obsolete feature it is warning about was removed nearly a year and a
half ago.
This allows compiling entire crates from memory or preprocessing source files before they are tokenized.
Minor API refactoring included, which is a [breaking-change] for libsyntax users:
* `ParseSess::{next_node_id, reserve_node_ids}` moved to rustc's `Session`
* `new_parse_sess` -> `ParseSess::new`
* `new_parse_sess_special_handler` -> `ParseSess::with_span_handler`
* `mk_span_handler` -> `SpanHandler::new`
* `default_handler` -> `Handler::new`
* `mk_handler` -> `Handler::with_emitter`
* `string_to_filemap(sess source, path)` -> `sess.codemap().new_filemap(path, source)`
Using regular pointer arithmetic to iterate collections of zero-sized types
doesn't work, because we'd get the same pointer all the time. Our
current solution is to convert the pointer to an integer, add an offset
and then convert back, but this inhibits certain optimizations.
What we should do instead is to convert the pointer to one that points
to an i8\*, and then use a LLVM GEP instructions without the inbounds
flag to perform the pointer arithmetic. This allows to generate pointers
that point outside allocated objects without causing UB (as long as you
don't dereference them), and it wraps around using two's complement,
i.e. it behaves exactly like the wrapping_* operations we're currently
using, with the added benefit of LLVM being able to better optimize the
resulting IR.
This commit implements a number of standard traits for the standard library's
process I/O handles. The `FromRaw{Fd,Handle}` traits are now implemented for the
`Stdio` type and the `AsRaw{Fd,Handle}` traits are now implemented for the
`Child{Stdout,Stdin,Stderr}` types. Additionally this implements the
`AsRawHandle` trait for `Child` on Windows.
The stability markers for these implementations mention that they are stable for
1.1 as I will nominate this commit for cherry-picking to beta.
This commits adds a method to the `std::process` module to get the process
identifier of the child as a `u32`. On Windows the underlying identifier is
already a `u32`, and on Unix the type is typically defined as `c_int` (`i32` for
almost all our supported platforms), but the actually pid is normally a small
positive number.
Eventually we may add functions to load information about a process based on its
identifier or the ability to terminate a process based on its identifier, but
for now this function should enable this sort of functionality to exist outside
the standard library.
Fix the link to the "static initialization order fiasco" discussion in the C++ Frequently Questioned Answers.
At present the link points to a mail message summarizing the decision not to have resumable exceptions, but the FAQ means to refer to a discussion of the "static initialization order fiasco". I've made my best guess at what it meant to refer to.
The Traits chapter uses "adding methods to `int`" as an example of "something bad", but there is no such thing as `int` anymore, right? So I changed it to `i32`.
