Matthias Krüger [Fri, 21 Jan 2022 21:03:15 +0000 (22:03 +0100)]
Rollup merge of #92843 - camelid:str-concat-sugg, r=davidtwco
Improve string concatenation suggestion
Before:
error[E0369]: cannot add `&str` to `&str`
--> file.rs:2:22
|
2 | let _x = "hello" + " world";
| ------- ^ -------- &str
| | |
| | `+` cannot be used to concatenate two `&str` strings
| &str
|
help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
|
2 | let _x = "hello".to_owned() + " world";
| ~~~~~~~~~~~~~~~~~~
After:
error[E0369]: cannot add `&str` to `&str`
--> file.rs:2:22
|
2 | let _x = "hello" + " world";
| ------- ^ -------- &str
| | |
| | `+` cannot be used to concatenate two `&str` strings
| &str
|
= note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
|
2 | let _x = "hello".to_owned() + " world";
| +++++++++++
Matthias Krüger [Fri, 21 Jan 2022 21:03:14 +0000 (22:03 +0100)]
Rollup merge of #92835 - iwanders:issue-66450-improve-cfg-error-message, r=nagisa
Improve error message for key="value" cfg arguments.
Hi, I ran into difficulties using the `--cfg` flag syntax, first hit when googling for the error was issue https://github.com/rust-lang/rust/issues/66450. Reading that issue, it sounded like the best way to improve the experience was to improve the error message, this is low risk and doesn't introduce any additional argument parsing.
The issue mentions that it is entirely dependent on the shell, while this may be true, I think guiding the the user into the realization that the quotes may need to be escaped is helpful. The two suggested escapings both work in Bash and in the Windows command prompt.
Matthias Krüger [Fri, 21 Jan 2022 21:03:12 +0000 (22:03 +0100)]
Rollup merge of #92467 - Aaron1011:extern-local-region, r=oli-obk
Ensure that early-bound function lifetimes are always 'local'
During borrowchecking, we treat any free (early-bound) regions on
the 'defining type' as `RegionClassification::External`. According
to the doc comments, we should only have 'external' regions when
checking a closure/generator.
However, a plain function can also have some if its regions
be considered 'early bound' - this occurs when the region is
constrained by an argument, appears in a `where` clause, or
in an opaque type. This was causing us to incorrectly mark these
regions as 'external', which caused some diagnostic code
to act as if we were referring to a 'parent' region from inside
a closure.
This PR marks all instantiated region variables as 'local'
when we're borrow-checking something other than a
closure/generator/inline-const.
Matthias Krüger [Fri, 21 Jan 2022 21:03:11 +0000 (22:03 +0100)]
Rollup merge of #91965 - ferrocene:pa-more-granular-exclude, r=Mark-Simulacrum
Add more granular `--exclude` in `x.py`
x.py has support for excluding some steps from the current invocation, but unfortunately that's not granular enough: some steps have the same name in different modules, and that prevents excluding only *some* of them.
As a practical example, let's say you need to run everything in `./x.py test` except for the standard library tests, as those tests require IPv6 and need to be executed on a separate machine. Before this commit, if you were to just run this:
./x.py test --exclude library/std
...the invocation would eventually fail, as that would not only exclude running the tests for the standard library (`library/std` in the `test` module), it would also exclude generating its documentation (`library/std` in the `doc` module), breaking linkchecker.
This commit adds support to the `--exclude` flag for prefixing paths with the name of the module their step is defined in, allowing the user to choose which module to exclude from:
./x.py test --exclude test::library/std
This maintains backward compatibility with existing invocations, while allowing more ganular exclusion. Examples of the behavior:
Note that this PR only changes the `--exclude` flag, and not in other `x.py` arguments or flags yet.
In the implementation I tried to limit the impact this would have with rustbuild as a whole as much as possible. The module name is extracted from the step by parsing the result of `std::any::type_name()`: unfortunately that output can change at any point in time, but IMO it's better than having to annotate all the existing and future `Step` implementations with the module name. I added a test to ensure the parsing works as expected, so hopefully if anyone makes changes to the output of `std::any::type_name()` they'll also notice they have to update rustbuild.
bors [Fri, 21 Jan 2022 10:38:30 +0000 (10:38 +0000)]
Auto merge of #92896 - lqd:update-deps, r=Mark-Simulacrum
Update some rustc dependencies to deduplicate them
This PR updates `rand` and `itertools` in rustc (not the whole workspace) in order to deduplicate them (and hopefully slightly improve compile times).
~~Currently, `object` is still duplicated, but https://github.com/rust-lang/thorin/pull/15 and updating `thorin` in the future will remove the use of version 0.27.~~ Update: Thorin 0.2 has now been released, and this PR updates `rustc_codegen_ssa` to use it and deduplicate the `object` crate.
There's a final tiny rustc dependency, `cfg-if`, which will be left: as both versions 0.1.x and 1.0 looked to be heavily depended on, they will require a few cascading updates to be removed.
Pietro Albini [Wed, 15 Dec 2021 11:51:26 +0000 (12:51 +0100)]
allow excluding paths only from a single module
x.py has support for excluding some steps from the invocation, but
unfortunately that's not granular enough: some steps have the same name
in different modules, and that prevents excluding only *some* of them.
As a practical example, let's say you need to run everything in `./x.py
test` except for the standard library tests, as those tests require IPv6
and need to be executed on a separate machine. Before this commit, if
you were to just run this:
./x.py test --exclude library/std
...the execution would fail, as that would not only exclude running the
tests for the standard library, it would also exclude generating its
documentation (breaking linkchecker).
This commit adds support for an optional module annotation in --exclude
paths, allowing the user to choose which module to exclude from:
./x.py test --exclude test::library/std
This maintains backward compatibility, but also allows for more ganular
exclusion. More examples on how this works:
bors [Fri, 21 Jan 2022 03:04:43 +0000 (03:04 +0000)]
Auto merge of #93138 - matthiaskrgr:rollup-m8akifd, r=matthiaskrgr
Rollup of 17 pull requests
Successful merges:
- #91032 (Introduce drop range tracking to generator interior analysis)
- #92856 (Exclude "test" from doc_auto_cfg)
- #92860 (Fix errors on blanket impls by ignoring the children of generated impls)
- #93038 (Fix star handling in block doc comments)
- #93061 (Only suggest adding `!` to expressions that can be macro invocation)
- #93067 (rustdoc mobile: fix scroll offset when jumping to internal id)
- #93086 (Add tests to ensure that `let_chains` works with `if_let_guard`)
- #93087 (Fix src/test/run-make/raw-dylib-alt-calling-convention)
- #93091 (⬆ chalk to 0.76.0)
- #93094 (src/test/rustdoc-json: Check for `struct_field`s in `variant_tuple_struct.rs`)
- #93098 (Show a more informative panic message when `DefPathHash` does not exist)
- #93099 (rustdoc: auto create output directory when "--output-format json")
- #93102 (Pretty printer algorithm revamp step 3)
- #93104 (Support --bless for pp-exact pretty printer tests)
- #93114 (update comment for `ensure_monomorphic_enough`)
- #93128 (Add script to prevent point releases with same number as existing ones)
- #93136 (Backport the 1.58.1 release notes to master)
Matthias Krüger [Thu, 20 Jan 2022 22:37:43 +0000 (23:37 +0100)]
Rollup merge of #93128 - pietroalbini:pa-verify-stable-version-number, r=Mark-Simulacrum
Add script to prevent point releases with same number as existing ones
This will hopefully prevent what happened today with #93110 and #93121, where we built point release artifacts without changing version numbers, thus requiring another PR to change the version number.
Matthias Krüger [Thu, 20 Jan 2022 22:37:41 +0000 (23:37 +0100)]
Rollup merge of #93104 - dtolnay:ppbless, r=Mark-Simulacrum
Support --bless for pp-exact pretty printer tests
I ran into this while working on the stack of PRs containing #93102. `x.py test src/test/pretty --bless` previously would `fatal` instead of blessing the input files.
Matthias Krüger [Thu, 20 Jan 2022 22:37:40 +0000 (23:37 +0100)]
Rollup merge of #93102 - dtolnay:ringbuffer, r=lcnr
Pretty printer algorithm revamp step 3
This PR follows #93065 as a third chunk of minor modernizations backported from https://github.com/dtolnay/prettyplease into rustc_ast_pretty.
I've broken this up into atomic commits that hopefully are sensible in isolation. At every commit, the pretty printer is compilable and has runtime behavior that is identical to before and after the PR. None of the refactoring so far changes behavior.
This PR is the last chunk of non-behavior-changing cleanup. After this the **next PR** will begin backporting behavior changes from `prettyplease`, starting with block indentation:
Matthias Krüger [Thu, 20 Jan 2022 22:37:39 +0000 (23:37 +0100)]
Rollup merge of #93099 - tomkris:rustdoc-fix, r=jsha
rustdoc: auto create output directory when "--output-format json"
This PR allows rustdoc to automatically create output directory in case it does not exist (when run with `--output-format json`).
This fixes rustdoc crash:
````
$ rustdoc --output-format json -Z unstable-options src/main.rs
error: couldn't generate documentation: No such file or directory (os error 2)
|
= note: failed to create or modify "doc/main.json"
error: aborting due to previous error
````
With this fix behavior of `rustdoc --output-format json` becomes consistent with `rustdoc --output-format html` (which already auto-creates output directory if it's missing)
Fix the test headers so that the test now runs on all intended platforms; it is currently ignored on all platforms because the headers are incorrect. Also comment out a couple of function calls that fail because of an unrelated problem, described in issue #91167.
Matthias Krüger [Thu, 20 Jan 2022 22:37:34 +0000 (23:37 +0100)]
Rollup merge of #93067 - jsha:fix-scroll-padding-top, r=GuillaumeGomez
rustdoc mobile: fix scroll offset when jumping to internal id
Followup to #92692. The semantics of `scroll-margin-top` are a little surprising - the attribute needs to be applied to the element that gets scrolled into the viewport, not the scrolling element.
This fixes an issue where clicking on a method (or other item) from the sidebar takes you to a scroll position where the topbar covers up the method name.
I'm interested in ideas for how to test this with browser-ui-test, but I think it doesn't yet have what I need. What I need is an assert that `<element>.getBoundingClientRect().y` is > 45.
Matthias Krüger [Thu, 20 Jan 2022 22:37:32 +0000 (23:37 +0100)]
Rollup merge of #93038 - GuillaumeGomez:block-doc-comments, r=notriddle
Fix star handling in block doc comments
Fixes #92872.
Some extra explanation about this PR and why https://github.com/rust-lang/rust/pull/92357 created this regression: when we merge doc comment kinds for example in:
```rust
/// he
/**
* hello
*/
#[doc = "boom"]
```
We don't want to remove the empty lines between them. However, to correctly compute the "horizontal trim", we still need it, so instead, I put back a part of the "vertical trim" directly in the "horizontal trim" computation so it doesn't impact the output buffer but allows us to correctly handle the stars.
Matthias Krüger [Thu, 20 Jan 2022 22:37:31 +0000 (23:37 +0100)]
Rollup merge of #92860 - CraftSpider:rustdoc-json-impl-ice, r=jsha
Fix errors on blanket impls by ignoring the children of generated impls
Related to #83718
We can safely skip the children, as they don't contain any new info, and may be subtly different for reasons hard to track down, in ways that are consistently worse than the actual generic impl.
Matthias Krüger [Thu, 20 Jan 2022 22:37:29 +0000 (23:37 +0100)]
Rollup merge of #91032 - eholk:generator-drop-tracking, r=nikomatsakis
Introduce drop range tracking to generator interior analysis
This PR addresses cases such as this one from #57478:
```rust
struct Foo;
impl !Send for Foo {}
let _: impl Send = || {
let guard = Foo;
drop(guard);
yield;
};
```
Previously, the `generator_interior` pass would unnecessarily include the type `Foo` in the generator because it was not aware of the behavior of `drop`. We fix this issue by introducing a drop range analysis that finds portions of the code where a value is guaranteed to be dropped. If a value is dropped at all suspend points, then it is no longer included in the generator type. Note that we are using "dropped" in a generic sense to include any case in which a value has been moved. That is, we do not only look at calls to the `drop` function.
There are several phases to the drop tracking algorithm, and we'll go into more detail below.
1. Use `ExprUseVisitor` to find values that are consumed and borrowed.
2. `DropRangeVisitor` uses consume and borrow information to gather drop and reinitialization events, as well as build a control flow graph.
3. We then propagate drop and reinitialization information through the CFG until we reach a fix point (see `DropRanges::propagate_to_fixpoint`).
4. When recording a type (see `InteriorVisitor::record`), we check the computed drop ranges to see if that value is definitely dropped at the suspend point. If so, we skip including it in the type.
## 1. Use `ExprUseVisitor` to find values that are consumed and borrowed.
We use `ExprUseVisitor` to identify the places where values are consumed. We track both the `hir_id` of the value, and the `hir_id` of the expression that consumes it. For example, in the expression `[Foo]`, the `Foo` is consumed by the array expression, so after the array expression we can consider the `Foo` temporary to be dropped.
In this process, we also collect values that are borrowed. The reason is that the MIR transform for generators conservatively assumes anything borrowed is live across a suspend point (see `rustc_mir_transform::generator::locals_live_across_suspend_points`). We match this behavior here as well.
## 2. Gather drop events, reinitialization events, and control flow graph
After finding the values of interest, we perform a post-order traversal over the HIR tree to find the points where these values are dropped or reinitialized. We use the post-order index of each event because this is how the existing generator interior analysis refers to the position of suspend points and the scopes of variables.
During this traversal, we also record branching and merging information to handle control flow constructs such as `if`, `match`, and `loop`. This is necessary because values may be dropped along some control flow paths but not others.
## 3. Iterate to fixed point
The previous pass found the interesting events and locations, but now we need to find the actual ranges where things are dropped. Upon entry, we have a list of nodes ordered by their position in the post-order traversal. Each node has a set of successors. For each node we additionally keep a bitfield with one bit per potentially consumed value. The bit is set if we the value is dropped along all paths entering this node.
To compute the drop information, we first reverse the successor edges to find each node's predecessors. Then we iterate through each node, and for each node we set its dropped value bitfield to the intersection of all incoming dropped value bitfields.
If any bitfield for any node changes, we re-run the propagation loop again.
## 4. Ignore dropped values across suspend points
At this point we have a data structure where we can ask whether a value is guaranteed to be dropped at any post order index for the HIR tree. We use this information in `InteriorVisitor` to check whether a value in question is dropped at a particular suspend point. If it is, we do not include that value's type in the generator type.
Note that we had to augment the region scope tree to include all yields in scope, rather than just the last one as we did before.
bors [Thu, 20 Jan 2022 20:44:14 +0000 (20:44 +0000)]
Auto merge of #93119 - matthiaskrgr:rollup-ku3cn5j, r=matthiaskrgr
Rollup of 13 pull requests
Successful merges:
- #89747 (Add MaybeUninit::(slice_)as_bytes(_mut))
- #89764 (Fix variant index / discriminant confusion in uninhabited enum branching)
- #91606 (Stabilize `-Z print-link-args` as `--print link-args`)
- #91694 (rustdoc: decouple stability and const-stability)
- #92183 (Point at correct argument when async fn output type lifetime disagrees with signature)
- #92582 (improve `_` constants in item signature handling)
- #92680 (intra-doc: Use the impl's assoc item where possible)
- #92704 (Change lint message to be stronger for &T -> &mut T transmute)
- #92861 (Rustdoc mobile: put out-of-band info on its own line)
- #92992 (Help optimize out backtraces when disabled)
- #93038 (Fix star handling in block doc comments)
- #93108 (:arrow_up: rust-analyzer)
- #93112 (Fix CVE-2022-21658)
Matthias Krüger [Thu, 20 Jan 2022 16:10:41 +0000 (17:10 +0100)]
Rollup merge of #93038 - GuillaumeGomez:block-doc-comments, r=notriddle
Fix star handling in block doc comments
Fixes #92872.
Some extra explanation about this PR and why https://github.com/rust-lang/rust/pull/92357 created this regression: when we merge doc comment kinds for example in:
```rust
/// he
/**
* hello
*/
#[doc = "boom"]
```
We don't want to remove the empty lines between them. However, to correctly compute the "horizontal trim", we still need it, so instead, I put back a part of the "vertical trim" directly in the "horizontal trim" computation so it doesn't impact the output buffer but allows us to correctly handle the stars.
Matthias Krüger [Thu, 20 Jan 2022 16:10:40 +0000 (17:10 +0100)]
Rollup merge of #92992 - kornelski:backtraceopt, r=Mark-Simulacrum
Help optimize out backtraces when disabled
The comment in `rust_backtrace_env` says:
> // If the `backtrace` feature of this crate isn't enabled quickly return
> // `None` so this can be constant propagated all over the place to turn
> // optimize away callers.
but this optimization has regressed, because the only caller of this function had an alternative path that unconditionally (and pointlessly) asked for a full backtrace, so the disabled state couldn't propagate.
I've added a getter for the full format that respects the feature flag, so that the caller will now be able to really optimize out the disabled backtrace path. I've also made `rust_backtrace_env` trivially inlineable when backtraces are disabled.
Matthias Krüger [Thu, 20 Jan 2022 16:10:39 +0000 (17:10 +0100)]
Rollup merge of #92861 - jsha:mobile-column-flex, r=GuillaumeGomez
Rustdoc mobile: put out-of-band info on its own line
Before this, the item name and the stability, source link, and "collapse
all docs" would compete for room on a single line, resulting in awkward
wrapping behavior on mobile. This gives a separate line for that
out-of-band information. It also removes the "copy path" icon on mobile
to make a little more room.
Matthias Krüger [Thu, 20 Jan 2022 16:10:37 +0000 (17:10 +0100)]
Rollup merge of #92704 - 5225225:std_mem_transmute_ref_t_mut_t, r=michaelwoerister
Change lint message to be stronger for &T -> &mut T transmute
The old message implied that it's only UB if you use the reference to mutate, which (as far as I know) is not true. As in, the following program has UB, and a &T -> &mut T transmute is effectively an `unreachable_unchecked`.
In the future, it might be a good idea to use the edition system to make this a hard error, since I don't think it is *ever* defined behaviour? Unless we rule that `&UnsafeCell<i32> -> &mut i32` is fine. (That, and you always could just use `.get()`, so you're not losing anything)
Matthias Krüger [Thu, 20 Jan 2022 16:10:36 +0000 (17:10 +0100)]
Rollup merge of #92680 - camelid:assoc-item-cleanup, r=petrochenkov
intra-doc: Use the impl's assoc item where possible
Before, the trait's associated item would be used. Now, the impl's
associated item is used. The only exception is for impls that use
default values for associated items set by the trait. In that case,
the trait's associated item is still used.
As an example of the old and new behavior, take this code:
trait MyTrait {
type AssocTy;
}
impl MyTrait for String {
type AssocTy = u8;
}
Before, when resolving a link to `String::AssocTy`,
`resolve_associated_trait_item` would return the associated item for
`MyTrait::AssocTy`. Now, it would return the associated item for
`<String as MyTrait>::AssocTy`, as it claims in its docs.
Matthias Krüger [Thu, 20 Jan 2022 16:10:35 +0000 (17:10 +0100)]
Rollup merge of #92582 - lcnr:generic-arg-infer, r=BoxyUwU
improve `_` constants in item signature handling
removing the "type" from the error messages does slightly worsen the error messages for types, but figuring out whether the placeholder is for a type or a constant and correctly dealing with that seemed fairly difficult to me so I took the easy way out :sparkles: Imo the error message is still clear enough.
Matthias Krüger [Thu, 20 Jan 2022 16:10:34 +0000 (17:10 +0100)]
Rollup merge of #92183 - tmandry:issue-74256, r=estebank
Point at correct argument when async fn output type lifetime disagrees with signature
Fixes most of #74256.
## Problems fixed
This PR fixes a couple of related problems in the error reporting code.
### Highlighting the wrong argument
First, the error reporting code was looking at the desugared return type of an `async fn` to decide which parameter to highlight. For example, a function like
Since `f: &'b u32` is returned but the output type is `&'a u32`, the error would occur when checking that `'a: 'b`.
The reporting code would look to see if the "offending" lifetime `'b` was included in the return type, and because the code was looking at the desugared future type, it was included. So it defaulted to reporting that the source of the other lifetime `'a` (the `self` type) was the problem, when it was really the type of `f`. (Note that if it had chosen instead to look at `'a` first, it too would have been included in the output type, and it would have arbitrarily reported the error (correctly this time) on the type of `f`.)
Looking at the actual future type isn't useful for this reason; it captures all input lifetimes. Using the written return type for `async fn` solves this problem and results in less confusing error messages for the user.
This isn't a perfect fix, unfortunately; writing the "manually desugared" form of the above function still results in the wrong parameter being highlighted. Looking at the output type of every `impl Future` return type doesn't feel like a very principled approach, though it might work. The problem would remain for function signatures that look like the desugared one above but use different traits. There may be deeper changes required to pinpoint which part of each type is conflicting.
### Lying about await point capture causing lifetime conflicts
The second issue fixed by this PR is the unnecessary complexity in `try_report_anon_anon_conflict`. It turns out that the root cause I suggested in https://github.com/rust-lang/rust/issues/76547#issuecomment-692863608 wasn't really the root cause. Adding special handling to report that a variable was captured over an await point only made the error messages less correct and pointed to a problem other than the one that actually occurred.
Given the above discussion, it's easy to see why: `async fn`s capture all input lifetimes in their return type, so holding an argument across an await point should never cause a lifetime conflict! Removing the special handling simplified the code and improved the error messages (though they still aren't very good!)
## Future work
* Fix error reporting on the "desugared" form of this code
* Get the `suggest_adding_lifetime_params` suggestion firing on these examples
* cc #42703, I think
Matthias Krüger [Thu, 20 Jan 2022 16:10:33 +0000 (17:10 +0100)]
Rollup merge of #91694 - euclio:stability-improvements, r=GuillaumeGomez
rustdoc: decouple stability and const-stability
This PR tweaks the stability rendering code to consider stability and const-stability separately. This fixes two issues:
- Stabilities that match the enclosing item are now always omitted, even if the item has const-stability as well (#90552)
- Const-stable unstable functions will now have their (const-) stability rendered.
Matthias Krüger [Thu, 20 Jan 2022 16:10:31 +0000 (17:10 +0100)]
Rollup merge of #89764 - tmiasko:uninhabited-enums, r=wesleywiser
Fix variant index / discriminant confusion in uninhabited enum branching
Fix confusion between variant index and variant discriminant. The pass
incorrectly assumed that for `Variants::Single` variant index is the same as
variant discriminant.
Matthias Krüger [Thu, 20 Jan 2022 16:10:30 +0000 (17:10 +0100)]
Rollup merge of #89747 - Amanieu:maybeuninit_bytes, r=m-ou-se
Add MaybeUninit::(slice_)as_bytes(_mut)
This adds methods to convert between `MaybeUninit<T>` and a slice of `MaybeUninit<u8>`. This is safe since `MaybeUninit<u8>` can correctly handle padding bytes in any `T`.
rustdoc: auto create output directory when "--output-format json"
This PR allows rustdoc to automatically create output directory in case
it does not exist (when run with `--output-format json`).
This fixes rustdoc crash:
````
$ rustdoc --output-format json -Z unstable-options src/main.rs
error: couldn't generate documentation: No such file or directory (os error 2)
|
= note: failed to create or modify "doc/main.json"
error: aborting due to previous error
````
With this fix behavior of `rustdoc --output-format json` becomes consistent
with `rustdoc --output-format html` (which already auto-creates output
directory if it's missing)
Before this, the item name and the stability, source link, and "collapse
all docs" would compete for room on a single line, resulting in awkward
wrapping behavior on mobile. This gives a separate line for that
out-of-band information. It also removes the "copy path" icon on mobile
to make a little more room.
Also, switch to flex-wrap: wrap, so anytime there's not enough room for
`source`, it gets bumped to the next line.
David Tolnay [Thu, 20 Jan 2022 02:51:07 +0000 (18:51 -0800)]
Eliminate offset number from Fits frames
PrintStackElems with pbreak=PrintStackBreak::Fits always carried a
meaningless value offset=0. We can combine the two types PrintStackElem
+ PrintStackBreak into one PrintFrame enum that stores offset only for
Broken frames.
David Tolnay [Thu, 20 Jan 2022 02:27:26 +0000 (18:27 -0800)]
Grow scan_stack in the conventional direction
The pretty printer algorithm involves 2 VecDeques: a ring-buffer of
tokens and a deque of ring-buffer indices. Confusingly, those two deques
were being grown in opposite directions for no good reason. Ring-buffer
pushes would go on the "back" of the ring-buffer (i.e. higher indices)
while scan_stack pushes would go on the "front" (i.e. lower indices).
This commit flips the scan_stack accesses to grow the scan_stack and
ring-buffer in the same direction, where push does the same
operation as a Vec push i.e. inserting on the high-index end.
Matthias Krüger [Wed, 19 Jan 2022 18:19:51 +0000 (19:19 +0100)]
Rollup merge of #93065 - dtolnay:ringbuffer, r=lcnr
Pretty printer algorithm revamp step 2
This PR follows #92923 as a second chunk of modernizations backported from https://github.com/dtolnay/prettyplease into rustc_ast_pretty.
I've broken this up into atomic commits that hopefully are sensible in isolation. At every commit, the pretty printer is compilable and has runtime behavior that is identical to before and after the PR. None of the refactoring so far changes behavior.
The general theme of this chunk of commits is: the logic in the old pretty printer is doing some very basic things (pushing and popping tokens on a ring buffer) but expressed in a too-low-level way that I found makes it quite complicated/subtle to reason about. There are a number of obvious invariants that are "almost true" -- things like `self.left == self.buf.offset` and `self.right == self.buf.offset + self.buf.data.len()` and `self.right_total == self.left_total + self.buf.data.sum()`. The reason these things are "almost true" is the implementation tends to put updating one side of the invariant unreasonably far apart from updating the other side, leaving the invariant broken while unrelated stuff happens in between. The following code from master is an example of this:
In this code the `advance_right` is reserving an entry into which to write a next token on the right side of the ring buffer, the `check_stack` is doing something totally unrelated to the right boundary of the ring buffer, and the `scan_push` is actually writing the token we previously reserved space for. Much of what this PR is doing is rearranging code to shrink the amount of stuff in between when an invariant is broken to when it is restored, until the whole thing can be factored out into one indivisible method call on the RingBuffer type.
The end state of the PR is that we can entirely eliminate `self.left` (because it's now just equal to `self.buf.offset` always) and `self.right` (because it's equal to `self.buf.offset + self.buf.data.len()` always) and the whole `Token::Eof` state which used to be the value of tokens that have been reserved space for but not yet written.
I found without these changes the pretty printer implementation to be hard to reason about and I wasn't able to confidently introduce improvements like trailing commas in `prettyplease` until after this refactor. The logic here is 43 years old at this point (Graydon translated it as directly as possible from the 1979 pretty printing paper) and while there are advantages to following the paper as closely as possible, in `prettyplease` I decided if we're going to adapt the algorithm to work better for Rust syntax, it was worthwhile making it easier to follow than the original.
Matthias Krüger [Wed, 19 Jan 2022 18:19:48 +0000 (19:19 +0100)]
Rollup merge of #92800 - ehuss:docs-fallback, r=Mark-Simulacrum
Add manifest docs fallback.
This adds a fallback so that the rustup manifest will contain the rust-docs component for all hosts. There is a mapping so that the docs that get downloaded are roughly close to the actual host. There inevitably will be things that don't match. Ideally the standard library docs would be the same for every platform (`cfg(doc)` goes a long way towards this), but there are still lots of minor differences.
Matthias Krüger [Wed, 19 Jan 2022 18:19:47 +0000 (19:19 +0100)]
Rollup merge of #92630 - steffahn:lift_bounds_on_BuildHasherDefault, r=yaahc
Change PhantomData type for `BuildHasherDefault` (and more)
Changes `PhantomData<H>` to `PhantomData<fn() -> H>` for `BuildHasherDefault`. This preserves the covariance of `H`, while it lifts the currently inferred unnecessary bounds like [`H: Send` for `BuildHasherDefault<H>: Send`](https://doc.rust-lang.org/1.57.0/std/hash/struct.BuildHasherDefault.html#impl-Send), etc.
_Edit:_ Also does a similar change for `iter::Empty` and `future::Pending`.
Matthias Krüger [Wed, 19 Jan 2022 18:19:45 +0000 (19:19 +0100)]
Rollup merge of #92316 - petrochenkov:extmangle, r=wesleywiser
mangling_v0: Skip extern blocks during mangling
There's no need to include the dummy `Nt` into the symbol name, items in extern blocks belong to their parent modules for all purposes except for inheriting the ABI and attributes.
Follow up to https://github.com/rust-lang/rust/pull/92032
(There's also a drive-by fix to the `rust-demangler` tool's tests, which don't run on CI, I initially attempted using them for testing this PR.)
bors [Wed, 19 Jan 2022 15:01:10 +0000 (15:01 +0000)]
Auto merge of #93069 - matthiaskrgr:rollup-gx1vkp7, r=matthiaskrgr
Rollup of 10 pull requests
Successful merges:
- #88642 (Formally implement let chains)
- #89621 (doc: guarantee call order for sort_by_cached_key)
- #91278 (Use iterator instead of recursion in `codegen_place`)
- #92124 (Little improves in CString `new` when creating from slice)
- #92783 (Annotate dead code lint with notes about ignored derived impls)
- #92797 (Remove horizontal lines at top of page)
- #92920 (Move expr- and item-related pretty printing functions to modules)
- #93041 (Remove some unused ordering derivations based on `DefId`)
- #93051 (Add Option::is_some_with and Result::is_{ok,err}_with)
- #93062 (Update books)