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
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
Changed toggle all sections key to `T`
Allows both `T` and `t`.
It had been [Shift]+[+] before.
In response to #33791.
cc @Manishearth
r? @GuillaumeGomez
Added a `rustdoc` shortcut for collapse/expand all
Now when the user presses the "+" key all sections will collapse/expand.
Also added a note to the help screen which describes this behavior.
This required increasing the height of the help screen.
rustdoc: Add doc snippets for trait impls, with a read more link
The read more link only appears if the documentation is more than one line long.
It currently does not appear on non-defaulted methods, since you can document them directly. I could make it so that default documentation gets forwarded if regular docs don't exist.
Fixes#33672
r? @alexcrichton
cc @steveklabnik
rustdoc: Make the #[stable(since)] version attribute clearer with a tooltip
Rustdoc's new 'since' version placement only shows the version number in which the item was marked stable. This gains space but might make the meaning of this version string less clear in the docs, so I tried to bring some explicitness in a tooltip.
track incr. comp. dependencies across crates
This PR refactors the compiler's incremental compilation hashing so that it can track dependencies across crates. The main bits are:
- computing a hash representing the metadata for an item we are emitting
- we do this by making `MetaData(X)` be the current task while computing metadata for an item
- this naturally registers reads from any tables and things that we read for that purpose
- we can then hash all the inputs to those tables
- tracking when we access metadata
- we do this by registering a read of `MetaData(X)` for each foreign item `X` whose metadata we read
- hashing metadata from foreign items
- we do this by loading up metadata from a file in the incr. comp. directory
- if there is no file, we use the SVH for the entire crate
There is one very simple test only at this point. The next PR will be focused on expanding out the tests.
Note that this is based on top of https://github.com/rust-lang/rust/pull/33228
r? @michaelwoerister
Remove ExplicitSelf from HIR
`self` argument is already kept in the argument list and can be retrieved from there if necessary, so there's no need for the duplication.
The same changes can be applied to AST, I'll make them in the next breaking batch.
The first commit also improves parsing of method declarations and fixes https://github.com/rust-lang/rust/issues/33413.
r? @eddyb
Clean up `hir::lowering`
Clean up `hir::lowering`:
- give lowering functions mutable access to the lowering context
- refactor the `lower_*` functions and other functions that take a lowering context into methods
- simplify the API that `hir::lowering` exposes to `driver`
- other miscellaneous cleanups
r? @nrc
Split the type context into a global and a local (inference-only) one.
After this change, each `InferCtxt` creates its own local type interner for types with inference by-products.
Most of the code which handles both a global and a local interner uses `'gcx` and `'tcx` for them.
A reference to the type context in that situation (e.g. `infcx.tcx`) is `TyCtxt<'a, 'gcx, 'tcx>`.
The global type context which used to be `&'a TyCtxt<'tcx>` is now `TyCtxt<'a, 'tcx, 'tcx>`.
In order to minimize the number of extra lifetime parameters, many functions became methods.
Where possible (some inherent impls), lifetime parameters were added on the impl, not each method.
As inference by-products no longer escape their inference contexts, memory usage is lower.
Example of `-Z time-passes` excerpt for `librustc`, stage1 (~100MB gains):
Before "rustc: Split local type contexts interners from the global one.":
```
time: 0.395; rss: 335MB item-types checking
time: 15.392; rss: 472MB item-bodies checking
time: 0.000; rss: 472MB drop-impl checking
time: 1.140; rss: 478MB const checking
time: 0.139; rss: 478MB privacy checking
time: 0.024; rss: 478MB stability index
time: 0.072; rss: 478MB intrinsic checking
time: 0.038; rss: 478MB effect checking
time: 0.255; rss: 478MB match checking
time: 0.128; rss: 484MB liveness checking
time: 1.372; rss: 484MB rvalue checking
time: 1.404; rss: 597MB MIR dump
time: 0.809; rss: 599MB MIR passes
```
After:
```
time: 0.467; rss: 337MB item-types checking
time: 17.443; rss: 395MB item-bodies checking
time: 0.000; rss: 395MB drop-impl checking
time: 1.423; rss: 401MB const checking
time: 0.141; rss: 401MB privacy checking
time: 0.024; rss: 401MB stability index
time: 0.116; rss: 401MB intrinsic checking
time: 0.038; rss: 401MB effect checking
time: 0.382; rss: 401MB match checking
time: 0.132; rss: 407MB liveness checking
time: 1.678; rss: 407MB rvalue checking
time: 1.614; rss: 503MB MIR dump
time: 0.957; rss: 512MB MIR passes
```
**NOTE**: Functions changed to methods weren't re-indented to keep this PR easier to review.
Once approved, the changes will be mechanically performed.
However, indentation changes of function arguments are there - and I believe there's a way to hide whitespace-only changes in diffs on GitHub.
rustdoc: remove artificial indentation of doctest code
The indentation makes the examples look nicer when printed (when is this done?), but breaks tests using multi-line string literals.
Fixes: #25944
