This commit generalises parsing of associative operators from left-associative
only (with some ugly hacks to support right-associative assignment) to properly
left/right-associative operators.
Parsing is still is not general enough to handle non-associative,
non-highest-precedence prefix or non-highest-precedence
postfix operators (e.g. `..` range syntax) and should be made to be.
Lastly, this commit adds support for parsing right-associative `<-` (left arrow)
operator with precedence higher than assignment as the operator for placement-in
feature.
---
This PR still needs various non-parser changes (e.g. src/grammar and tests) and I’m still working on these; the meat of the PR can already be reviewed, though, I think.
Please review carefully. I made sure that quirks I have discovered so far are preserved (see e.g. https://github.com/rust-lang/rust/issues/29071) and am looking for more corner cases as I continue to work on tests et al, but there may be something I haven’t noticed or accounted for.
EDIT: I’m also not sure I managed to preserve all the semantics with the range operator inside non-trivial expressions since these are a mess at the moment. Crater runs would be nice.
Change error reporting of conflicting loans to stop earlier after printing
an error for a given borrow, instead of proceeding to error on possibly every
issued loan. This keeps us down to O(n) errors (for n problem lines), instead
of O(n^2) errors in some cases.
Fixes#27485.
This commit generalises parsing of associative operators from left-associative
only (with some ugly hacks to support right-associative assignment) to properly
left/right-associative operators.
Parsing still is not general enough to handle non-associative,
non-highest-precedence prefix or non-highest-precedence postfix operators (e.g.
`..` range syntax), though. That should be fixed in the future.
Lastly, this commit adds support for parsing right-associative `<-` (left arrow)
operator with precedence higher than assignment as the operator for placement-in
feature.
this has the funky side-effect of also allowing constant evaluation of function calls to functions that are not `const fn` as long as `check_const` didn't mark that function `NOT_CONST`
It's still not possible to call a normal function from a `const fn`, but let statements' initialization value can get const evaluated (this caused the fallout in the overflowing tests)
we can now do this:
```rust
const fn add(x: usize, y: usize) -> usize { x + y }
const ARR: [i32; add(1, 2)] = [5, 6, 7];
```
also added a test for destructuring in const fn args
```rust
const fn i((a, b): (u32, u32)) -> u32 { a + b } //~ ERROR: E0022
```
This is a **[breaking change]**, since it turns some runtime panics into compile-time errors. This statement is true for ANY improvement to the const evaluator.
I could have added a check for explicit recursion, as irregular types
tend to cause selection errors, but I am not sufficiently sure that
cannot be bypassed.
Fixes#22919Fixes#25639Fixes#26548
As displayed before this commit, I found the book confusing in its
explanation of `#`-led comments in `rust` blocks. Possibly the
biggest confusion was because the many-dashes construct does not
become an HR element in the Markdown translator used, so things were
not being properly set off.
This change should more clearly show the as-rendered content as
rendered, and the as-coded content as code.
These commits revert https://github.com/rust-lang/rust/pull/28504 and add a regression test pointed out by @petrochenkov, it's not immediately clear with the regression that the accessibility check should be removed, so for now preserve the behavior on stable by default.
r? @nrc
I didn't see anything particularly weird here. The last commit has the only changes I'm not 100% sure about.
I ignored tables.rs since it's genrated, but I updated the python script that generates it.
?r @nrc
This PR switches the implemented ordering from `unsafe const fn` (as was in the original RFC) to `const unsafe fn` (which is what the lang team decided on)
Previously, if you copied a signature from a trait definition such as:
```rust
fn foo<'a>(&'a Bar) -> bool {}
```
and moved it into an `impl`, there would be an error message:
"unexpected token `'a`"
Adding to the error message that a pattern is expected should help
users to find the actual problem with using a lifetime here.
I somehow missed a word behind the numbers while going through this section, don't know what the best approach would be though since "**available** addresses" sounds good to me, too".
instead of this panic:
```
thread '<main>' panicked at 'index out of bounds: the len is 1 but the
index is 1', src/libcollections/vec.rs:1110
```
It still panics, just like `-h` does, so it should be okay in this
regard.
As displayed before this commit, I found the book confusing in its
explanation of `#`-led comments in `rust` blocks. Possibly the
biggest confusion was because the many-dashes construct does not
become an HR element in the Markdown translator used, so things were
not being properly set off.
This change should more clearly show the as-rendered content as
rendered, and the as-coded content as code.
This commit stabilizes and deprecates library APIs whose FCP has closed in the
last cycle, specifically:
Stabilized APIs:
* `fs::canonicalize`
* `Path::{metadata, symlink_metadata, canonicalize, read_link, read_dir, exists,
is_file, is_dir}` - all moved to inherent methods from the `PathExt` trait.
* `Formatter::fill`
* `Formatter::width`
* `Formatter::precision`
* `Formatter::sign_plus`
* `Formatter::sign_minus`
* `Formatter::alternate`
* `Formatter::sign_aware_zero_pad`
* `string::ParseError`
* `Utf8Error::valid_up_to`
* `Iterator::{cmp, partial_cmp, eq, ne, lt, le, gt, ge}`
* `<[T]>::split_{first,last}{,_mut}`
* `Condvar::wait_timeout` - note that `wait_timeout_ms` is not yet deprecated
but will be once 1.5 is released.
* `str::{R,}MatchIndices`
* `str::{r,}match_indices`
* `char::from_u32_unchecked`
* `VecDeque::insert`
* `VecDeque::shrink_to_fit`
* `VecDeque::as_slices`
* `VecDeque::as_mut_slices`
* `VecDeque::swap_remove_front` - (renamed from `swap_front_remove`)
* `VecDeque::swap_remove_back` - (renamed from `swap_back_remove`)
* `Vec::resize`
* `str::slice_mut_unchecked`
* `FileTypeExt`
* `FileTypeExt::{is_block_device, is_char_device, is_fifo, is_socket}`
* `BinaryHeap::from` - `from_vec` deprecated in favor of this
* `BinaryHeap::into_vec` - plus a `Into` impl
* `BinaryHeap::into_sorted_vec`
Deprecated APIs
* `slice::ref_slice`
* `slice::mut_ref_slice`
* `iter::{range_inclusive, RangeInclusive}`
* `std::dynamic_lib`
Closes#27706Closes#27725
cc #27726 (align not stabilized yet)
Closes#27734Closes#27737Closes#27742Closes#27743Closes#27772Closes#27774Closes#27777Closes#27781
cc #27788 (a few remaining methods though)
Closes#27790Closes#27793Closes#27796Closes#27810
cc #28147 (not all parts stabilized)
This commit stabilizes and deprecates library APIs whose FCP has closed in the
last cycle, specifically:
Stabilized APIs:
* `fs::canonicalize`
* `Path::{metadata, symlink_metadata, canonicalize, read_link, read_dir, exists,
is_file, is_dir}` - all moved to inherent methods from the `PathExt` trait.
* `Formatter::fill`
* `Formatter::width`
* `Formatter::precision`
* `Formatter::sign_plus`
* `Formatter::sign_minus`
* `Formatter::alternate`
* `Formatter::sign_aware_zero_pad`
* `string::ParseError`
* `Utf8Error::valid_up_to`
* `Iterator::{cmp, partial_cmp, eq, ne, lt, le, gt, ge}`
* `<[T]>::split_{first,last}{,_mut}`
* `Condvar::wait_timeout` - note that `wait_timeout_ms` is not yet deprecated
but will be once 1.5 is released.
* `str::{R,}MatchIndices`
* `str::{r,}match_indices`
* `char::from_u32_unchecked`
* `VecDeque::insert`
* `VecDeque::shrink_to_fit`
* `VecDeque::as_slices`
* `VecDeque::as_mut_slices`
* `VecDeque::swap_remove_front` - (renamed from `swap_front_remove`)
* `VecDeque::swap_remove_back` - (renamed from `swap_back_remove`)
* `Vec::resize`
* `str::slice_mut_unchecked`
* `FileTypeExt`
* `FileTypeExt::{is_block_device, is_char_device, is_fifo, is_socket}`
* `BinaryHeap::from` - `from_vec` deprecated in favor of this
* `BinaryHeap::into_vec` - plus a `Into` impl
* `BinaryHeap::into_sorted_vec`
Deprecated APIs
* `slice::ref_slice`
* `slice::mut_ref_slice`
* `iter::{range_inclusive, RangeInclusive}`
* `std::dynamic_lib`
Closes#27706Closes#27725
cc #27726 (align not stabilized yet)
Closes#27734Closes#27737Closes#27742Closes#27743Closes#27772Closes#27774Closes#27777Closes#27781
cc #27788 (a few remaining methods though)
Closes#27790Closes#27793Closes#27796Closes#27810
cc #28147 (not all parts stabilized)
instead of this panic:
```
thread '<main>' panicked at 'index out of bounds: the len is 1 but the
index is 1', src/libcollections/vec.rs:1110
```
It still panics, just like `-h` does, so it should be okay in this
regard.
The new bots we have may conflict with one another on base ports, causing tests
to fail. For example the linux-musl-64-opt and linux-64-opt bots are using the
same base port right now, causing some spurious failures every now and then.
Previously, if you copied a signature from a trait definition such as:
```
fn foo<'a>(&'a Bar) -> bool {}
```
and moved it into an `impl`, there would be an error message:
"unexpected token `'a`"
Adding to the error message that a pattern is expected should help
users to find the actual problem with using a lifetime here.
PR for #28157. At the moment, `rustc` emits a warning when a bare semicolon is encountered (could also be a fail, but I think this is a backwards incompatible change).
Also I am not sure where the best place for a test for that warning would be. Seems run-pass tests do not check warnings.
Give preference to projections from where-clauses over those from trait definitions. This makes #28871 work again, though I think there's more to fix in this general area.
r? @arielb1
cc @brson (fixes regression)
The new bots we have may conflict with one another on base ports, causing tests
to fail. For example the linux-musl-64-opt and linux-64-opt bots are using the
same base port right now, causing some spurious failures every now and then.
Fixes#29184
This adds an error message for the use of the reserved `typeof` keyword, instead of reporting an ICE.
Also adds a `compile-fail` test.
I chose to add a `span_err` instead of removing to parser code, as to preserve the reservation of `typeof`.
It's possible that there is some meaning I'm not grasping from the headers "Traits bounds for generic functions" and "Traits bounds for generic structs", but they seem to me like they could be clearer and more grammatically correct.
Qualified paths allow full path after the `>::`. For example
```rust
<T as Foo>::U::generic_method::<f64>()
```
The example is taken from `test/run-pass/associated-item-long-paths.rs`.
{BTree,Hash}{Map,Set} will not update their key if it already exists, which
can matter with more complex keys. This behavior is now documented.
Fixes#26888
{BTree,Hash}{Map,Set} will not update their key if it already exists, which
can matter with more complex keys. This behavior is now documented.
Fixes#26888
Qualified paths allow full path after the `>::`. For example
```rust
<T as Foo>::U::generic_method::<f64>()
```
The example is taken from `test/run-pass/associated-item-long-paths.rs`.
Currently it is possible to do the following:
- define a module named `Foo` and then a unit or tuple struct also named `Foo`
- define any struct named `Foo` and then a module named `Foo`
This commit introduces a warning for both of these cases.
trait definitions, and give prefence to the former. This is consistent
with what we do for selection. It also works around a limitation
that was leading to #28871.
When reading this paragraph, the beginning Rust programmer is starting
to write a Hello World program. We have just told her to name the file
`main.rs`, and immediately afterward, a `hello_world.rs` is mentioned.
I changed this to an unrelated filename (incidentally one that appears
in this repository) to make it clear that this is just an example.
Also, wording it as a declarative sentence rather than an imperative one
further separates it from the Hello World instructions in this section.
r? @steveklabnik
(Let me know if I'm sending too many PRs -- I can batch up TRPL edits, say, per chapter, if that works better. Or I can just refrain from editing TRPL as I read through it, if these are not sufficiently useful.)
The paragraph here seemed confusing, so I reworded it. Also added
another possible reason why `curl | sh` might be objectionable to users.
r? @steveklabnik
The paragraph here seemed confusing, so I reworded it. Also added
another possible reason why `curl | sh` might be objectionable to users.
r? @steveklabnik
This is a pretty trivial change. My eye caught some inconsistent whitespace while perusing compiler errors tonight. Specifically, I changed `//correct` to `// correct`, and got rid of some trailing whitespace that isn't seen in other code snippets.
This commit expands the "supported platforms" section of the book to include
documentation on the tiers that Rust currently has as well as organizing all
supported platforms into these various tiers. Infrastructure improvements over
the next few months are likely to change the location of may of these platforms
over, but for now this should faithfully represent what we've got today!
When reading this paragraph, the beginning Rust programmer is starting
to write a Hello World program. We have just told her to name the file
`main.rs`, and immediately afterward, a `hello_world.rs` is mentioned.
I changed this to an unrelated filename (incidentally one that appears
in this repository) to make it clear that this is just an example.
Also, wording it as a declarative sentence rather than an imperative one
further separates it from the Hello World instructions in this section.
This commit expands the "supported platforms" section of the book to include
documentation on the tiers that Rust currently has as well as organizing all
supported platforms into these various tiers. Infrastructure improvements over
the next few months are likely to change the location of may of these platforms
over, but for now this should faithfully represent what we've got today!
Yay, markdown isn't standardized and rustbook's parser has subtle incompatibilities with Github's! So in the Github preview you don't see that this list fails to separate from the previous paragraph. I think this should fix it, but I didn't check.
This is a WIP PR for my implementation of drain over the VecDeque data structure supporting ranges. It brings the VecDeque drain implementation in line with Vec's.
Tests haven't been written for the new function yet.
The attributes are copied from the item for which the trait impl is derived
I think now we can close these two issues:
https://github.com/rust-lang/rust/issues/13054 - `allow`, `deny` etc. were already copied, now `stable` and `unstable` are copied as well.
https://github.com/rust-lang/rust/issues/18969 - I'm not sure this is needed, insta-stability were good enough so far, copied stability will be better. Nonetheless, it can be subsumed by some more general mechanism for supplying arbitrary not necessarily stability related attributes (for example `inline`) to derived impls and their methods (I haven't found an open issue for such mechanism).
r? @alexcrichton
This is for discoverability. If someone wants to know what `?Sized` means, then
Sized will be the only keyword they can use to search; so even though this is
technically a language matter, it makes sense to document it where it will be
looked for.
Remove leading newlines; replace lines containing only whitespace with empty lines; replace multiple trailing newlines with a single newline; remove trailing whitespace in lines.
This PR was created semiautomatically.
To augment the didactic effect, made placed the thread::sleep_ms call in the last example, so that there will be time for the other locks to happen; without this, I was unable to observe the deadlock in over 1,000 runs when there was no left-handed philosopher.
I wasn't sure whether `Ordering::Relaxed` meant `Monotonic` or `Unordered`, so I checked the compiler sources and found 206af38e74/src/librustc_trans/trans/intrinsic.rs (L846) which appears conclusive. Adding this answer to the documentation.
Due to the way iterators work, the std::iter module is chock full of
structs that you, humble Rust programmer, will never actually use.
However, they have URLs, and therefore get linked to, because they are
real structs that do exist.
So, rather than just have a tiny sentence about each one of them,
this patch adds links back to the functions and methods on Iterator
which actually create the structs, where helpful documentation already
exists.
