feat: Add "make tuple" tactic to term search
Follow up to https://github.com/rust-lang/rust-analyzer/pull/16092
Now term search also supports tuples.
```rust
let a: i32 = 1;
let b: f64 = 0.0;
let c: (i32, (f64, i32)) = todo!(); // Finds (a, (b, a))
```
In addition to new tactic that handles tuples I changed how the generics are handled.
Previously it tried all possible options from types we had in scope but now it only tries useful ones that help us directly towards the goal or at least towards calling some other function.
This changes O(2^n) to O(n^2) where n is amount of rounds which in practice allows using types that take generics for multiple rounds (previously limited to 1). Average case that also used to be exponential is now roughly linear.
This means that deeply nested generics also work.
````rust
// Finds all valid combos, including `Some(Some(Some(...)))`
let a: Option<Option<Option<bool>>> = todo!();
````
_Note that although the complexity is smaller allowing more types with generics the search overall slows down considerably. I hope it's fine tho as the autocomplete is disabled by default and for code actions it's not super slow. Might have to tweak the depth hyper parameter tho_
This resulted in a huge increase of results found (benchmarks on `ripgrep` crate):
Before
````
Tail Expr syntactic hits: 149/1692 (8%)
Tail Exprs found: 749/1692 (44%)
Term search avg time: 18ms
```
After
```
Tail Expr syntactic hits: 291/1692 (17%)
Tail Exprs found: 1253/1692 (74%)
Term search avg time: 139ms
````
Most changes are local to term search except some tuple related stuff on `hir::Type`.
performance: Speed up Method Completions By Taking Advantage of Orphan Rules
(Continues https://github.com/rust-lang/rust-analyzer/pull/16498)
This PR speeds up method completions by doing two things without regressing `analysis-stats`[^1]:
- Filter candidate traits prior to calling `iterate_path_candidates` by relying on orphan rules (see below for a slightly more in-depth explanation). When generating completions [on `slog::Logger`](5e9e59c312/common/src/ledger.rs (L78)) in `oxidecomputer/omicron` as a test, this PR halved my completion times—it's now 454ms cold and 281ms warm. Before this PR, it was 808ms cold and 579ms warm.
- Inline some of the method candidate checks into `is_valid_method_candidate` and remove some unnecessary visibility checks. This was suggested by `@Veykril` in [this comment](https://github.com/rust-lang/rust-analyzer/pull/16498#issuecomment-1929864427).
We filter candidate traits by taking advantage of orphan rules. For additional details, I'll rely on `@WaffleLapkin's` explanation [from Zulip](420942417):
> A type `A` can only implements traits which
> 1. Have a blanket implementation (`impl<T> Trait for T {}`)
> 2. Have implementation for `A` (`impl Trait for A {}`)
>
> Blanket implementation can only exist in `Trait`'s crate. Implementation for `A` can only exist in `A`'s or `Trait`'s crate.
Big thanks to Waffle for its keen observation!
---
I think some additional improvements are possible:
- `for_trait_and_self_ty` seemingly does not distinguish between `&T`, `&mut T`, or `T`, resulting in seemingly irrelevant traits like `tokio::io::AsyncWrite` being being included for, e.g., `&slog::Logger`. I don't know they're being considered due to the [autoref/autoderef behavior](a02a219773/crates/hir-ty/src/method_resolution.rs (L945-L962)), but I wonder if it'd make sense to filter by mutability earlier and not consider trait implementations that require `&mut T` when we only have a `&T`.
- The method completions [spend a _lot_ of time in unification](421072356), and while there might be low-hanging fruit there, it might make more sense to wait for the new trait solver in `rustc`. I dunno.
[^1]: The filtering occurs outside of typechecking, after all.
fix: Don't panic on synthetic syntax in inference diagnostics
Temporary fix for https://github.com/rust-lang/rust-analyzer/issues/16682
We ought to rethink how we attach diagnostics to things, as IDs don't work for `format_args` like that!
fix: panic when inlining callsites inside macros' parameters
Close#16660, #12429, #10695.
When `inline_into_callers` encounters callsites in macros parameters, it can lead to panics. Since there is no perfect way to handle macros, this PR directly filters out these cases.
internal: Remove salsa compile_fail tests
I can't figure out how to reproduce them, but hopefully fixes these:
`get_path_for_executable` will now first check `$CARGO_HOME` before falling back to searching `$PATH`.
rustup is the recommended way to manage rust toolchains, therefore should be picked before the
system toolchain.
fix: Recompiles due to RUSTC_BOOTSTRAP
Some packages (e.g. thiserror) force a recompile if the value of the `RUSTC_BOOTSTRAP` env var changes. RA sets the variable to 1 in order to enable rustc / cargo unstable options. This causes flapping recompiles when building outside of RA.
Fixes#15057
internal: Optimize salsa memory usage
Reduces memory on self by ~20mb for me, there is a few more mb to save here if we made LRU caching opt-in, as currently every entry in a memoized query will store an `AtomicUsize` for the LRU.
`cargo rustc -- <args>` first builds dependencies then calls `rustc <args>` for the current package. Here, we don't want to build dependencies, we just want to call `rustc --print`. An unstable `cargo rustc` `--print` command bypasses building dependencies first. This speeds up execution of this code path and ensures RA doesn't recompile dependencies with the `RUSTC_BOOTSRAP=1` env var flag set.
Note that we must pass `-Z unstable-options` twice, first to enable the `cargo` unstable `--print` flag, then later to enable the unstable `rustc` `target-spec-json` print request.
Some packages (e.g. thiserror) force a recompile if the value of the `RUSTC_BOOTSTRAP` env var changes. RA sets the variable to 1 in order to enable rustc / cargo unstable options it uses. This causes flapping recompiles when building outside of RA.
As of Cargo 1.75 the `--keep-going` flag is stable. This change uses the flag without `RUSTC_BOOTSTRAP` if the Cargo version is >= 1.75, and drops `--keep-going` otherwise. This fixes build script recompilation.
internal: Attempt to add a timeout to rustc-tests
Looks like some new test is stuck, this might help with figuring that out, though it unfortunately won't if its a chalk hang (which is the most likely)
fix: server hanging up on build script task
This should fix https://github.com/rust-lang/rust-analyzer/issues/16614, can't say for certain since it might be not 100% reproducible... We really need to replace the current workspace fetching logic, it is completely unreadable and incredibly difficult to follow. I don't really understand how the server even got to hang here honestly (I would expect it to loop re-fetching build scripts, but not hang).
