Remove global error count checks from typeck
Some of these are not reachable anymore, others can now rely on information local to the current typeck run. One check was actually invalid, because it was relying on wfcheck running before typeck, which is not guaranteed in the query system and usually easy to create ICEing examples for via const eval (which runs typeck before wfcheck)
Add `as_lang_item` to `LanguageItems`, new trait solver
Add `as_lang_item` which turns `DefId` into a `TraitSolverLangItem` in the new trait solver, so we can turn the large chain of if statements in `assemble_builtin_impl_candidates` into a match instead.
r? lcnr
linker: Link dylib crates by path
Linkers seem to support linking dynamic libraries by path.
Not sure why the previous scheme with splitting the path into a directory (passed with `-L`) and a name (passed with `-l`) was used (upd: likely due to https://github.com/rust-lang/rust/pull/126094#issuecomment-2155063414).
When we split a library path `some/dir/libfoo.so` into `-L some/dir` and `-l foo` we add `some/dir` to search directories for *all* libraries looked up by the linker, not just `foo`, and `foo` is also looked up in *all* search directories not just `some/dir`.
Technically we may find some unintended libraries this way.
Therefore linking dylibs via a full path is both simpler and more reliable.
It also makes the set of search directories more easily reproducible when we need to lookup some native library manually (like in https://github.com/rust-lang/rust/pull/123436).
Re-implement a type-size based limit
r? lcnr
This PR reintroduces the type length limit added in #37789, which was accidentally made practically useless by the caching changes to `Ty::walk` in #72412, which caused the `walk` function to no longer walk over identical elements.
Hitting this length limit is not fatal unless we are in codegen -- so it shouldn't affect passes like the mir inliner which creates potentially very large types (which we observed, for example, when the new trait solver compiles `itertools` in `--release` mode).
This also increases the type length limit from `1048576 == 2 ** 20` to `2 ** 24`, which covers all of the code that can be reached with craterbot-check. Individual crates can increase the length limit further if desired.
Perf regression is mild and I think we should accept it -- reinstating this limit is important for the new trait solver and to make sure we don't accidentally hit more type-size related regressions in the future.
Fixes#125460
Actually report normalization-based type errors correctly for alias-relate obligations in new solver
We have some special casing to report type mismatch errors that come from projection predicates, but we don't do that for alias-relate obligations. This PR implements that. There's a bit of code duplication, but 🤷
Best reviewed without whitespace.
r? lcnr
Check alias args for WF even if they have escaping bound vars
#### What
This PR stops skipping arguments of aliases if they have escaping bound vars, instead recursing into them and only discarding the resulting obligations referencing bounds vars.
#### An example:
From the test:
```
trait Trait {
type Gat<U: ?Sized>;
}
fn test<T>(f: for<'a> fn(<&'a T as Trait>::Gat<&'a [str]>)) where for<'a> &'a T: Trait {}
//~^ ERROR the size for values of type `[()]` cannot be known at compilation time
fn main() {}
```
We now prove that `str: Sized` in order for `&'a [str]` to be well-formed. We were previously unconditionally skipping over `&'a [str]` as it referenced a buond variable. We now recurse into it and instead only discard the `[str]: 'a` obligation because of the escaping bound vars.
#### Why?
This is a change that improves consistency about proving well-formedness earlier in the pipeline, which is necessary for future work on where-bounds in binders and correctly handling higher-ranked implied bounds. I don't expect this to fix any unsoundness.
#### What doesn't it fix?
Specifically, this doesn't check projection predicates' components are well-formed, because there are too many regressions: https://github.com/rust-lang/rust/pull/123737#issuecomment-2052198478
Since this codegen flag now only controls LLVM-generated comments rather than
all assembly comments, make the name more accurate (and also match Clang).
Rewrite handling of universe-leaking placeholder regions into outlives constraints
This commit prepares for Polonius by moving handling of leak check/universe errors out of the inference step by rewriting any universe error into an outlives-static constraint.
This variant is a work in progress but seems to pass most tests.
Note that a few debug assertions no longer hold; a few extra eyes on those changes are appreciated!
Fix `FnMut::call_mut`/`Fn::call` shim for async closures that capture references
I adjusted async closures to be able to implement `Fn` and `FnMut` *even if* they capture references, as long as those references did not need to borrow data from the closure captures themselves. See #125259.
However, when I did this, I didn't actually relax an assertion in the `build_construct_coroutine_by_move_shim` shim code, which builds the `Fn`/`FnMut`/`FnOnce` implementations for async closures. Therefore, if we actually tried to *call* `FnMut`/`Fn` on async closures, it would ICE.
This PR adjusts this assertion to ensure that we only capture immutable references in closures if they implement `Fn`/`FnMut`. It also adds a bunch of tests and makes more of the async-closure tests into `build-pass` since we often care about these tests actually generating the right closure shims and stuff. I think it might be excessive to *always* use build-pass here, but 🤷 it's not that big of a deal.
Fixes#127019Fixes#127012
r? oli-obk
Parenthesize break values containing leading label
The AST pretty printer previously produced invalid syntax in the case of `break` expressions with a value that begins with a loop or block label.
```rust
macro_rules! expr {
($e:expr) => {
$e
};
}
fn main() {
loop {
break expr!('a: loop { break 'a 1; } + 1);
};
}
```
`rustc -Zunpretty=expanded main.rs `:
```console
#![feature(prelude_import)]
#![no_std]
#[prelude_import]
use ::std::prelude::rust_2015::*;
#[macro_use]
extern crate std;
macro_rules! expr { ($e:expr) => { $e }; }
fn main() { loop { break 'a: loop { break 'a 1; } + 1; }; }
```
The expanded code is not valid Rust syntax. Printing invalid syntax is bad because it blocks `cargo expand` from being able to format the output as Rust syntax using rustfmt.
```console
error: parentheses are required around this expression to avoid confusion with a labeled break expression
--> <anon>:9:26
|
9 | fn main() { loop { break 'a: loop { break 'a 1; } + 1; }; }
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
help: wrap the expression in parentheses
|
9 | fn main() { loop { break ('a: loop { break 'a 1; }) + 1; }; }
| + +
```
This PR updates the AST pretty-printer to insert parentheses around the value of a `break` expression as required to avoid this edge case.
And update the comment. Clearly the return type of this function was
changed at some point in the past, but its name and comment weren't
updated to match.
The number of source code bytes can't exceed a `u32`'s range, so a token
position also can't. This reduces the size of `Parser` and
`LazyAttrTokenStreamImpl` by eight bytes each.
Currently it uses a mixture of functional style (`flat_map`) and
imperative style (`push`), which is a bit hard to read. This commit
converts it to fully imperative, which is more concise and avoids the
need for `smallvec`.
I.e. change the return type from `TokenStream` to `Vec<TokenTree>`.
Most of the callsites require a `TokenStream`, but the recursive call
used to create `target_tokens` requires a `Vec<TokenTree>`. It's easy
to convert a `Vec<TokenTree>` to a `TokenStream` (just call
`TokenStream::new`) but it's harder to convert a `TokenStream` to a
`Vec<TokenTree>` (either iterate/clone/collect, or use `Lrc::into_inner`
if appropriate).
So this commit changes the return value to simplify that `target_tokens`
call site.
