In Debian and Ubuntu, there are some patches that change the rustc/fonts
directory to a symlink to the system fonts. This triggers a latent bug
in linkchecker, as the DirEntry filetype isn't a dir but later on the
file itself, when opened, is one, triggering an unreachable!() clause.

This patch fixes the situation by using std::fs::metadata, which goes
through symlinks.

I'd have added a test case but `tidy` doesn't seem to like symlinks, and
moreover I'm not sure how Git deals with symlinks on Windows.

Signed-off-by: Simon Chopin <[email protected]>

fixes rust-lang#91139
fixes rust-lang#91069

- Implement lowering for subtype goals
- Use correct lang item for Generator trait
- Use `lower_into` for lowering `ty::Variance`

This is required to avoid creating large numbers of universes from each
Chalk query, while still having enough universe information for lifetime
errors.

canonicalize_chalk_query -> canonicalize_query_preserving_universes

Revert spurious changes included in PR

Co-authored-by: David Tolnay <[email protected]>

Add 2 tests

fixes rust-lang#91139
fixes rust-lang#91069

…, r=jackh726

fix ICE when parsing lifetime as function argument

I don't really like this, but we basically need to emit an error instead of just delaying an bug, because there are too many places in the AST that aren't covered by my previous PRs...

cc: rust-lang#93282 (comment)

Add some known GAT bugs as tests

In the spirit of rust-lang/compiler-team#476

These tests are marked as "check-fail", but also commented with "this should pass". This many of the open GAT issues that are accepted bugs.

r? `@nikomatsakis`

Pretty print ItemKind::Use in rustfmt style

This PR backports the formatting for `use` items from https://github.com/dtolnay/prettyplease into rustc_ast_pretty.

Before:

```rust
use core::{cmp::{Eq, Ord, PartialEq, PartialOrd},
    convert::{AsMut, AsRef, From, Into},
    iter::{DoubleEndedIterator, ExactSizeIterator, Extend, FromIterator,
    IntoIterator, Iterator},
    marker::{Copy as Copy, Send as Send, Sized as Sized, Sync as Sync, Unpin
    as U}, ops::{*, Drop, Fn, FnMut, FnOnce}};
```

After:

```rust
use core::{
    cmp::{Eq, Ord, PartialEq, PartialOrd},
    convert::{AsMut, AsRef, From, Into},
    iter::{
        DoubleEndedIterator, ExactSizeIterator, Extend, FromIterator,
        IntoIterator, Iterator,
    },
    marker::{
        Copy as Copy, Send as Send, Sized as Sized, Sync as Sync, Unpin as U,
    },
    ops::{*, Drop, Fn, FnMut, FnOnce},
};
```

…niverses, r=jackh726

Improve chalk integration

- Support subtype bounds in chalk lowering
- Handle universes in canonicalization
- Handle type parameters in chalk responses
- Use `chalk_ir::LifetimeData::Empty` for `ty::ReEmpty`
- Remove `ignore-compare-mode-chalk` for tests that no longer hang (they may still fail or ICE)

This is enough to get a hello world program to compile with `-Zchalk` now. Some of the remaining issues that are needed to get Chalk integration working on larger programs are:

- rust-lang/chalk#234
- rust-lang/chalk#548
- rust-lang/chalk#734
- Generators are handled differently in chalk and rustc

r? ``@jackh726``

…Mark-Simulacrum

linkchecker: fix panic on directory symlinks

In Debian and Ubuntu, there are some patches that change the rustc/fonts
directory to a symlink to the system fonts. This triggers a latent bug
in linkchecker, as the DirEntry filetype isn't a dir but later on the
file itself, when opened, is one, triggering an unreachable!() clause.

This patch fixes the situation by using std::fs::metadata, which goes
through symlinks.

I'd have added a test case but `tidy` doesn't seem to like symlinks, and
moreover I'm not sure how Git deals with symlinks on Windows.

Signed-off-by: Simon Chopin <[email protected]>

…Mark-Simulacrum

tidy: Extend error code check

We discovered in rust-lang#93845 that the error code tidy check didn't check everything: if you remove an error code from the listing even if it has an explanation, then it should error.

It also allowed me to put back `E0192` in that listing as well.

r? ``@Mark-Simulacrum``

Add missing release notes for rust-lang#85200

Fixes rust-lang#93894