Fix OOM caused by term search
The issue came from multi Cartesian product for exprs with many (25+) arguments, each having multiple options.
The solution is two fold:
### Avoid blowing up in Cartesian product
**Before the logic was:**
1. Find expressions for each argument/param - there may be many
2. Take the Cartesian product (which blows up in some cases)
4. If there are more than 2 options throw them away by squashing them to `Many`
**Now the logic is:**
1. Find expressions for each argument/param and squash them to `Many` if there are more than 2 as otherwise we are guaranteed to also have more than 2 after taking the product which means squashing them anyway.
2. Take the Cartesian product on iterator
3. Start consuming it one by one
4. If there are more than 2 options throw them away by squashing them to `Many` (same as before)
This is also why I had to update some tests as the expressions get squashed to many more eagerly.
### Use fuel to avoid long search times and high memory usage
Now all the tactics use `should_continue: Fn() -> bool` to chech if they should keep iterating _(Similarly to chalk)_.
This reduces the search times by a magnitude, for example from ~139ms/hole to ~14ms/hole for `ripgrep` crate.
There are slightly less expressions found, but I think speed gain worth it for usability.
Also note that syntactic hits decreases more because of squashing so you simple need to run search multiple times to get full terms.
Also the worst case time (For example `nalgebra` crate cus it has tons of generics) has search times mostly under 200ms.
Benchmarks on `ripgrep` crate
Before:
```
Tail Expr syntactic hits: 291/1692 (17%)
Tail Exprs found: 1253/1692 (74%)
Term search avg time: 139ms
````
After:
```
Tail Expr syntactic hits: 239/1692 (14%)
Tail Exprs found: 1226/1692 (72%)
Term search avg time: 14ms
```
When viewing traces, it's slightly confusing when the span name doesn't
match the function name. Ensure the names are consistent.
(It might be worth moving most of these to use #[tracing::instrument]
so the name can never go stale. @davidbarsky suggested that is marginally
slower, so I've just done the simple change here.)
Better inline preview for postfix completion
Better inline preview for postfix completion, a proper implementation of c5686c8941.
Here editors may filter completion item with the text within `delete_range`, so we need to include the `receiver text` in the `lookup` (aka `FilterText` in LSP spec) for editors to find the completion item. (See https://github.com/rust-lang/rust-analyzer/issues/17036#issuecomment-2056614180, Thanks to [pascalkuthe](https://github.com/pascalkuthe))
Changed the completion item source_range to match
the replaced text. Though in VS Code it may not be
disturbing because the snippet is previewed in a
box, but in Helix editor, it's previewed by applying
the main text edit.
feat: Syntax highlighting improvements
Specifically
- Adds a new `constant` modifier, attached to keyword `const` (except for `*const ()` and `&raw const ()`), `const` items and `const` functions
- Adds (or rather reveals) `associated` modifier for associated items
- Fixes usage of the standard `static` modifier, now it acts like `associated` except being omitted for methods.
- Splits `SymbolKind::Function` into `Function` and `Method`. We already split other things like that (notable self param from params), so the split makes sense in general as a lot special cases around it anyways.
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`.
Add completions to show only traits in trait `impl` statement
This is prerequisite PR for adding the assist mentioned in #12500
P.S: If wanted, I will add the implementation of the assist in this PR as well.
Abstract more over ItemTreeLoc-like structs
Allows reducing some code duplication by using functions generic over said structs. The diff isn't negative due to me adding some additional impls for completeness.
internal: even more `tracing`
As part of profiling completions, I added some additional spans and moved `TyBuilder::subst_for_def` closer to its usage site (the latter had a small impact on completion performance. Thanks for the tip, Lukas!)
This commit also adds `tracing` to NotificationDispatcher/RequestDispatcher,
bumps `rust-analyzer-salsa` to 0.17.0-pre.6, `always-assert` to 0.2, and
removes the homegrown `hprof` implementation in favor of a vendored
tracing-span-tree.
feat: "Normalize import" assist and utilities for normalizing use trees
- Add import/use tree normalization utilities
- Add "normalize import" assist
- Update "merge imports" assist to always apply to the covering use item except for nested use tree selections
- Update "merge imports" assist to avoid adding unnecessary braces when merging nested use tree selections
See [this discussion](https://github.com/rust-lang/rust-analyzer/pull/16372#discussion_r1457244321) for the motivation for the new "normalize import" assist and changes to the "merge imports" assist.
