…sysroot source

See
https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/False.20error.20report.20for.20.60rust-analyzer.28private-field.29.60
for further discussion; previously this had various bugs.

I tested go-to-definition on:
- `use std::io::Write` in `src/bootstrap/setup.rs`
- `use std::cell::RefCell` in `src/librustdoc/core.rs`
- `use rustc_span::symbol::sym` in `src/librustdoc/core.rs`
- `use std::fmt` in `compiler/rustc_span/src/symbol.rs`
- `Global` in `library/alloc/src/alloc/tests.rs`

The following things still don't work:
- `Global.deallocate` in alloc/tests.rs. This function is under
  `cfg(not(test))`, so it can't be enabled without disabling RA in
  `tests.rs` altogether. I think this might be fixable by moving
  `library/alloc/src/alloc/tests.rs` to
  `library/alloc/tests/alloc/lib.rs`, so it's in a different crate, but
  I'd like to avoid blocking this improvement on that change.

…ppear

…tead

…of-different-items-with-same-name, r=aDotInTheVoid

Fix json reexports of different items with same name

Fixes  rust-lang#107677.

I renamed `from_item_id*` functions into `id_from_item` instead because it makes more sense now. I also simplified the logic around it a bit so that the `ids` function will now directly pass `&clean::Item` to `id_from_item` and the ID will be consistently generated (it caused an issue when I updated the ID for imports).

So now, the big change of this PR: I changed how imports' ID is generated: it now includes the target item's ID at the end of the ID. It's to prevent two reexported items with the same name (but different types).

r? `@aDotInTheVoid`

…nks-starting-with-whitespace, r=petrochenkov

Correctly handle links starting with whitespace

Part of rust-lang#107995.

I just got this issue, wrote a fix and then saw the issue. So here's the PR. ^^'

r? `@petrochenkov`

Change src/etc/vscode_settings.json to always treat ./library as the sysroot source

See
https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/False.20error.20report.20for.20.60rust-analyzer.28private-field.29.60 for further discussion; previously this had various bugs.

I tested go-to-definition on:
- `use std::io::Write` in `src/bootstrap/setup.rs`
- `use std::cell::RefCell` in `src/librustdoc/core.rs`
- `use rustc_span::symbol::sym` in `src/librustdoc/core.rs`
- `use std::fmt` in `compiler/rustc_span/src/symbol.rs`
- `Global` in `library/alloc/src/alloc/tests.rs`

The following things still don't work:
- `Global.deallocate` in alloc/tests.rs. This function is under `cfg(not(test))`, so it can't be enabled without disabling RA in `tests.rs` altogether. I think this might be fixable by moving `library/alloc/src/alloc/tests.rs` to `library/alloc/tests/alloc/lib.rs`, so it's in a different crate, but I'd like to avoid blocking this improvement on that change.

cc `@thomcc` `@BoxyUwU` `@spastorino` - you've had issues with RA in the past, does this fix them? Are there any other use cases I should test? You can try these changes out by running `cp src/etc/vscode_settings.json .vscode/settings.json`, or running `x setup` and picking a random profile (it won't overwrite config.toml if it already exists). See rust-lang#108135 for plans to make updating the config easier.

r? `@Veykril`

…s-2, r=jackh726

Fix RPITITs in default trait methods (by assuming projection predicates in param-env)

Instead of having special projection logic that allows us to turn `ProjectionTy(RPITIT, [Self#0, ...])` into `OpaqueTy(RPITIT, [Self#0, ...])`, we can instead augment the param-env of default trait method bodies to assume these as projection predicates. This should allow us to only project where we're allowed to!

In order to make this work without introducing a bunch of cycle errors, we additionally tweak the `OpaqueTypeExpander` used by `ParamEnv::with_reveal_all_normalized` to not normalize the right-hand side of projection predicates. This should be fine, because if we use the projection predicate to normalize some other projection type, we'll continue to normalize the opaque that it gets projected to.

This also makes it possible to support default trait methods with RPITITs in an associated-type based RPITIT lowering strategy without too much extra effort.

Fixes rust-lang#107002
Alternative to rust-lang#108142

Download rustfmt regardless of rustc being set in config.toml

Fixes rust-lang#81155

cc : rust-lang#108210 for exact error details