Delete the `cfg(not(parallel))` serial compiler
Since it's inception a long time ago, the parallel compiler and its cfgs have been a maintenance burden. This was a necessary evil the allow iteration while not degrading performance because of synchronization overhead.
But this time is over. Thanks to the amazing work by the parallel working group (and the dyn sync crimes), the parallel compiler has now been fast enough to be shipped by default in nightly for quite a while now.
Stable and beta have still been on the serial compiler, because they can't use `-Zthreads` anyways.
But this is quite suboptimal:
- the maintenance burden still sucks
- we're not testing the serial compiler in nightly
Because of these reasons, it's time to end it. The serial compiler has served us well in the years since it was split from the parallel one, but it's over now.
Let the knight slay one head of the two-headed dragon!
#113349
Note that the default is still 1 thread, as more than 1 thread is still fairly broken.
cc `@onur-ozkan` to see if i did the bootstrap field removal correctly, `@SparrowLii` on the sync parts
Since it's inception a long time ago, the parallel compiler and its cfgs
have been a maintenance burden. This was a necessary evil the allow
iteration while not degrading performance because of synchronization
overhead.
But this time is over. Thanks to the amazing work by the parallel
working group (and the dyn sync crimes), the parallel compiler has now
been fast enough to be shipped by default in nightly for quite a while
now.
Stable and beta have still been on the serial compiler, because they
can't use `-Zthreads` anyways.
But this is quite suboptimal:
- the maintenance burden still sucks
- we're not testing the serial compiler in nightly
Because of these reasons, it's time to end it. The serial compiler has
served us well in the years since it was split from the parallel one,
but it's over now.
Let the knight slay one head of the two-headed dragon!
move all mono-time checks into their own folder, and their own query
The mono item collector currently also drives two mono-time checks: the lint for "large moves", and the check whether function calls are done with all the required target features.
Instead of doing this "inside" the collector, this PR refactors things so that we have a new `rustc_monomorphize::mono_checks` module providing a per-instance query that does these checks. We already have a per-instance query for the ABI checks, so this should be "free" for incremental builds. Non-incremental builds might do a bit more work now since we now have two separate MIR visits (in the collector and the mono-time checks) -- but one of them is cached in case the MIR doesn't change, which is nice.
This slightly changes behavior of the large-move check since the "move_size_spans" deduplication logic now only works per-instance, not globally across the entire collector.
Cc `@saethlin` since you're also doing some work related to queries and caching and monomorphization, though I don't know if there's any interaction here.
Make sure to ignore elided lifetimes when pointing at args for fulfillment errors
See the comment I left in the code.
---
If we have something like:
```
fn foo<'a, T: 'a + BoundThatIsNotSatisfied>() {}
```
And the user turbofishes just the type args:
```
foo::<()>();
```
Then if we try pointing at `()` (i.e. the type argument for `T`), we don't actually consider the possibility that the lifetimes may have been left out of the turbofish. We try indexing incorrectly into the HIR args, and bail on the suggestion.
Consolidate type system const evaluation under `traits::evaluate_const`
Part of #130704Fixes#128232Fixes#118545
Removes `ty::Const::{normalize_internal, eval_valtree}` and `InferCtxt::(try_)const_eval_resolve`, consolidating the associated logic into `evaluate_const` in `rustc_trait_selection`. This results in an API for `ty::Const` that is free of any normalization/evaluation functions that would be incorrect to use under `min_generic_const_args`/`associated_const_equality`/`generic_const_exprs` or, more generally, that would be incorrect to use in the presence of generic type system constants.
Moving this logic to `rustc_trait_selection` and out of `rustc_middle` is also a pre-requisite for ensuring that we do not evaluate constants whose where clauses do not hold.
From this point it should be relatively simple (hah) to implement more complex normalization of type system constants such as: checking wf'ness before invoking CTFE machinery, or being able to normalize const aliases that still refer to generic parameters.
r? `@compiler-errors`
Update grammar in std::cell docs.
Using "having" in both the leading sentence and the bullets is unnecessary.
It makes it read as "it is only possible to have having several immutable...".
test(configure): cover `parse_args` in `src/bootstrap/configure.py`
I was reading `src/bootstrap/configure.py` and `parse_args` function there seems complex. So I added some tests to cover it and prevent regressions.
Feature gate yield expressions not in 2024
This changes it so that yield expressions are no longer allowed in the 2024 edition without a feature gate. We are currently only reserving the `gen` keyword in the 2024 edition, and not allowing anything else to be implicitly enabled by the edition.
In practice this doesn't have a significant difference since yield expressions can't really be used outside of coroutines or gen blocks, which have their own feature gates. However, it does affect what is accepted pre-expansion, and I would feel more comfortable not allowing yield expressions.
I believe the stabilization process for gen blocks or coroutines will not need to check the edition here, so this shouldn't ever be needed.
Remove attributes from generics in built-in derive macros
Related issue #132561
Removes all attributes from generics in the expanded implementations of built-in derive macros.
Rollup of 8 pull requests
Successful merges:
- #132487 (Provide placeholder generics for traits in "no method found for type parameter" suggestions)
- #132627 (cleanup: Remove outdated comment of `thir_body`)
- #132653 (Don't use `maybe_unwrap_block` when checking for macro calls in a block expr)
- #132793 (Update mdbook to 0.4.42)
- #132847 (elem_offset / subslice_range: use addr() instead of 'as usize')
- #132869 (split up the first paragraph of doc comments for better summaries)
- #132929 (Check for null in the `alloc_zeroed` example)
- #132933 (Make sure that we suggest turbofishing the right type arg for never suggestion)
r? `@ghost`
`@rustbot` modify labels: rollup
Make sure that we suggest turbofishing the right type arg for never suggestion
I had a bug where rust would suggest the wrong arg to turbofish `()` if there were any early-bound lifetimes...
r? WaffleLapkin
split up the first paragraph of doc comments for better summaries
used `./x clippy -Aclippy::all '-Wclippy::too_long_first_doc_paragraph' library/core library/alloc` to find these issues.
Update mdbook to 0.4.42
This updates mdbook to 0.4.42
Changelog: https://github.com/rust-lang/mdBook/blob/master/CHANGELOG.md#mdbook-0441
There were some significant changes that I would like to get early testing on.
This also updates rust-by-example which was required due to an update to the theme file.
Don't use `maybe_unwrap_block` when checking for macro calls in a block expr
Fixes#131915
Using `maybe_unwrap_block` to determine if we are looking at a `{ mac_call!{} }` will fail sometimes as `mac_call!{}` could be a `StmtKind::MacCall` not a `StmtKind::Expr`. This caused the def collector to think that `{ mac_call!{} }` was a non-trivial const argument and create a definition for it even though it should not.
r? `@compiler-errors` cc `@camelid`
cleanup: Remove outdated comment of `thir_body`
When typeck fails, `thir_body` returns `ErrorGuaranteed` rather than empty body.
No other code follows this outdated description except `check_unsafety`, which is also cleaned up in this PR.
Provide placeholder generics for traits in "no method found for type parameter" suggestions
In the diagnostics for the error ``no method named `method` found for type parameter `T` in the current scope [E0599]``, the compiler will suggest adding bounds on `T` for traits that define a method named `method`. However, these suggestions didn't include any generic arguments, so applying them would result in a `missing generics for trait` or `missing lifetime specifier` error. This PR adds placeholder arguments to the suggestion in such cases. Specifically, I tried to base the placeholders off of what's done in suggestions for when generics are missing or too few are provided:
- The placeholder for a parameter without a default is the name of the parameter.
- Placeholders are not provided for parameters with defaults.
Placeholder arguments are enclosed in `/*` and `*/`, and the applicability of the suggestion is downgraded to `Applicability::HasPlaceholders` if any placeholders are provided.
Fixes#132407
