Batch up libsyntax breaking changes
Batch of the following syntax-[breaking-change] changes:
- #34213: Add a variant `Macro` to `TraitItemKind`
- #34368: Merge the variant `QPath` of `PatKind` into the variant `PatKind::Path`
- #34385: Move `syntax::ast::TokenTree` into a new module `syntax::tokenstream`
- #33943:
- Remove the type parameter from `visit::Visitor`
- Remove `attr::WithAttrs` -- use `attr::HasAttrs` instead.
- Change `fold_tt`/`fold_tts` to take token trees by value and avoid wrapping token trees in `Rc`.
- Remove the field `ctxt` of `ast::Mac_`
- Remove inherent method `attrs()` of types -- use the method `attrs` of `HasAttrs` instead.
- #34316:
- Remove `ast::Decl`/`ast::DeclKind` and add variants `Local` and `Item` to `StmtKind`.
- Move the node id for statements from the `StmtKind` variants to a field of `Stmt` (making `Stmt` a struct instead of an alias for `Spanned<StmtKind>`)
- Rename `ast::ExprKind::Again` to `Continue`.
- #34339: Generalize and abstract `ThinAttributes` to `ThinVec<Attribute>`
- Use `.into()` in convert between `Vec<Attribute>` and `ThinVec<Attribute>`
- Use autoderef instead of `.as_attr_slice()`
- #34436: Remove the optional expression from `ast::Block` and instead use a `StmtKind::Expr` at the end of the statement list.
- #34403: Move errors into a separate crate (unlikely to cause breakage)
This PR refactors the 'errors' part of libsyntax into its own crate (librustc_errors). This is the first part of a few refactorings to simplify error reporting and potentially support more output formats (like a standardized JSON output and possibly an --explain mode that can work with the user's code), though this PR stands on its own and doesn't assume further changes.
As part of separating out the errors crate, I have also refactored the code position portion of codemap into its own crate (libsyntax_pos). While it's helpful to have the common code positions in a separate crate for the new errors crate, this may also enable further simplifications in the future.
rustdoc: Fix a couple of issues with src links to external crates
- src links/redirects to extern fn from another crate had an extra '/'.
- src links to `pub use` of a crate module had an extra '/'.
- src links to renamed reexports from another crate used the new name
for the link but should use the original name.
Fixes: #34274
Implementation of #34168
r? @brson
cc @alexcrichton
cc @steveklabnik
cc @jonathandturner
I only updated `librustc_privacy/diagnostics.rs`, and I already found a case where the code doesn't throw the expected error code (E0448).
Fixes#34168.
- src links/redirects to extern fn from another crate had an extra '/'.
- src links to `pub use` of a crate module had an extra '/'.
- src links to renamed reexports from another crate used the new name
for the link but should use the original name.
When items are inlined from extern crates, the filename in the debug info
is taken from the FileMap that's serialized in the rlib metadata.
Currently this is just FileMap.name, which is whatever path is passed to rustc.
Since libcore and libstd are built by invoking rustc with relative paths,
they wind up with relative paths in the rlib, and when linked into a binary
the debug info uses relative paths for the names, but since the compilation
directory for the final binary, tools trying to read source filenames
will wind up with bad paths. We noticed this in Firefox with source
filenames from libcore/libstd having bad paths.
This change stores an absolute path in FileMap.abs_path, and uses that
if available for writing debug info. This is not going to magically make
debuggers able to find the source, but it will at least provide sensible
paths.
rustdoc: Fix redirect pages for renamed reexports
We need to use the name of the target not the name of the current item
when creating the link.
An example in `std` is [`std::sys::ext`](https://doc.rust-lang.org/nightly/std/sys/ext/index.html).
rustdoc: Don't inline #[doc(hidden)] pub use
Currently if a `#[doc(hidden)] pub use` item is inlined the `hidden`
attribute is ignored so the item can appear in the docs. By never inlining
such imports, they can be stripped.
An example in `std` is [`__OsLocalKeyInner`](https://doc.rust-lang.org/nightly/std/thread/struct.__OsLocalKeyInner.html) which clearly should not be documented.
rustdoc: Don't generate empty files for stripped items
We need to traverse stripped modules to generate redirect pages, but we shouldn't generate
anything else for them.
This now renders the file contents to a Vec before writing it to a file in one go. I think
that's probably a better strategy anyway.
Fixes: #34025
Currently if a `#[doc(hidden)] pub use` item is inlined the `hidden`
attribute is ignored so the item can appear in the docs. By never inlining
such imports, they can be stripped.
Refactor away the prelude injection fold
Instead, just inject `#[prelude_import] use [core|std]::prelude::v1::*;` at the crate root while injecting `extern crate [core|std];` and process `#[no_implicit_prelude]` attributes in `resolve`.
r? @nrc
rustdoc: Fix generating redirect pages for statics and consts
These were missing from the cache for some reason meaning the redirect pages failed to render.
rustc: add ReErased to be used by trait selection, MIR and trans.
`ReErased` replaces `ReStatic` (i.e. `'static`) for erasing regions.
Using a distinct lifetime helps prevent accidental mix-ups between the two.
It also allows cleaner type printing (see test changes), including in symbol names:
```rust
str..pattern..CharSearcher$LT$$u27$static$GT$::drop.30560::h840c2f2afc03bbea // before
str..pattern..CharSearcher::drop.30561::h6bd31d2af614377a // after
```
Not that we should be producing symbols this way, but it's still better.
As far as I know whether a trait was derived or not does not change the
public API so there is no need to include this information in the docs.
This title currently just adds an extra divide in the list of trait
implementations which I don't think needs to be there.
Projection cache and better warnings for #32330
This PR does three things:
- it lays the groundwork for the more precise subtyping rules discussed in #32330, but does not enable them;
- it issues warnings when the result of a leak-check or subtyping check relies on a late-bound region which will late become early-bound when #32330 is fixed;
- it introduces a cache for projection in the inference context.
I'm not 100% happy with the approach taken by the cache here, but it seems like a step in the right direction. It results in big wins on some test cases, but not as big as previous versions -- I think because it is caching the `Vec<Obligation>` (whereas before I just returned the normalized type with an empty vector). However, that change was needed to fix an ICE in @alexcrichton's future-rs module (I haven't fully tracked the cause of that ICE yet). Also, because trans/the collector use a fresh inference context for every call to `fulfill_obligation`, they don't profit nearly as much from this cache as they ought to.
Still, here are the results from the future-rs `retry.rs`:
```
06:26 <nmatsakis> time: 6.246; rss: 44MB item-bodies checking
06:26 <nmatsakis> time: 54.783; rss: 63MB translation item collection
06:26 <nmatsakis> time: 140.086; rss: 86MB translation
06:26 <nmatsakis> time: 0.361; rss: 46MB item-bodies checking
06:26 <nmatsakis> time: 5.299; rss: 63MB translation item collection
06:26 <nmatsakis> time: 12.140; rss: 86MB translation
```
~~Another example is the example from #31849. For that, I get 34s to run item-bodies without any cache. The version of the cache included here takes 2s to run item-bodies type-checking. An alternative version which doesn't track nested obligations takes 0.2s, but that version ICEs on @alexcrichton's future-rs (and may well be incorrect, I've not fully convinced myself of that). So, a definite win, but I think there's definitely room for further progress.~~
Pushed a modified version which improves performance of the case from #31849:
```
lunch-box. time rustc --stage0 ~/tmp/issue-31849.rs -Z no-trans
real 0m33.539s
user 0m32.932s
sys 0m0.570s
lunch-box. time rustc --stage2 ~/tmp/issue-31849.rs -Z no-trans
real 0m0.195s
user 0m0.154s
sys 0m0.042s
```
Some sort of cache is also needed for unblocking further work on lazy normalization, since that will lean even more heavily on the cache, and will also require cycle detection.
r? @arielb1
We need to traverse stripped modules to generate redirect pages, but we shouldn't generate
anything else for them.
This now renders the file contents to a Vec before writing it to a file in one go. I think
that's probably a better strategy anyway.
This indicates whether this `BoundRegion` will change from late to early
bound when issue 32330 is fixed. It also indicates the function on
which the lifetime is declared.
print enum variant fields in docs
Right now we are repeating enum variants at the top, because the fields aren't shown with the actual docs. It's very annoying to have to scroll up and down to have both docs and field info. For struct variants we already list the fields.
enum docs look like this after this PR:
There are degenerate cases for enum tuple variants with lots of fields:
I was thinking that we could move the docs below the variant (slightly indented) or list the variant fields vertically instead of horizontally
r? @steveklabnik
