fix: Some file watching related vfs fixes
Fixes https://github.com/rust-lang/rust-analyzer/issues/15554, additionally it seems that client side file watching was broken on windows this entire time, this PR switches `DidChangeWatchedFilesRegistrationOptions` to use relative glob patterns which do work on windows in VSCode.
Have Derive Attribute share a token tree with it's proc macros.
The goal of this PR is to stop creating a token tree for each derive proc macro.
This is done by giving the derive proc macros an id to its parent derive element.
From running the analysis stat on the rust analyzer project I did see a small memory decrease.
```
Inference: 42.80s, 362ginstr, 591mb
MIR lowering: 8.67s, 67ginstr, 291mb
Mir failed bodies: 18 (0%)
Data layouts: 85.81ms, 609minstr, 8mb
Failed data layouts: 135 (6%)
Const evaluation: 440.57ms, 5235minstr, 13mb
Failed const evals: 1 (0%)
Total: 64.16s, 552ginstr, 1731mb
```
After Change
```
Inference: 40.32s, 340ginstr, 593mb
MIR lowering: 7.95s, 62ginstr, 292mb
Mir failed bodies: 18 (0%)
Data layouts: 87.97ms, 591minstr, 8mb
Failed data layouts: 135 (6%)
Const evaluation: 433.38ms, 5226minstr, 14mb
Failed const evals: 1 (0%)
Total: 60.49s, 523ginstr, 1680mb
```
Currently this breaks the expansion for the actual derive attribute.
## TODO
- [x] Pick a better name for the function `smart_macro_arg`
fix: Fix projects depending on `rustc_private` hanging
If loading the root fails, we'll hang up in this loop as we never inserted the entry that asserts we already visited a package. This fixes that
Fixes https://github.com/rust-lang/rust-analyzer/issues/16902
Resolve whether `$pat` is `$pat_param` or not via 🌟hygiene🌟
Before we just picked the edition from the macro def which is wrong, since a macro call can produce the fragment kind from a different definition site.
fix: Fix project discovery not checking whether the `Cargo.toml` actually exists
Got dropped in https://github.com/rust-lang/rust-analyzer/pull/16889, somehow r-a's codebase itself doesn't even run into this so I didn't see it when testing ...
internal: Enforce utf8 paths
Cargo already requires this, and I highly doubt r-a works with non-utf8 paths generally either. This just makes dealing with paths a lot easier.
Add fuel to match checking
Exhaustiveness checking is NP-hard hence can take extremely long to check some specific matches. This PR makes ehxaustiveness bail after a set number of steps. I chose a bound that takes ~100ms on my machine, which should be more than enough for normal matches.
I'd like someone with less recent hardware to run the test to see if that limit is low enough for them. Also curious if the r-a team thinks this is a good ballpark or if we should go lower/higher. I don't have much data on how complex real-life matches get, but we can definitely go lower than `500 000` steps.
The second commit is a drive-by soundness fix which doesn't matter much today but will matter once `min_exhaustive_patterns` is stabilized.
Fixes https://github.com/rust-lang/rust-analyzer/issues/9528 cc `@matklad`
