This story begins in #8384, where we added a smart test for our syntax
highting, which run the algorithm on synthetic files of varying length
in order to guesstimate if the complexity is O(N^2) or O(N)-ish.
The test turned out to be pretty effective, and flagged #9031 as a
change that makes syntax highlighting accidentally quadratic. There was
much rejoicing, for the time being.
Then, lnicola asked an ominous question[1]: "Are we sure that the time
is linear right now?"
Of course it turned out that our sophisticated non-linearity detector
*was* broken, and that our syntax highlighting *was* quadratic.
Investigating that, many brave hearts dug deeper and deeper into the
guts of rust-analyzer, only to get lost in a maze of traits delegating
to traits delegating to macros.
Eventually, matklad managed to peel off all layers of abstraction one by
one, until almost nothing was left. In fact, the issue was discovered in
the very foundation of the rust-analyzer -- in the syntax trees.
Worse, it was not a new problem, but rather a well-know, well-understood
and event (almost) well-fixed (!) performance bug.
The problem lies within `SyntaxNodePtr` type -- a light-weight "address"
of a node in a syntax tree [3]. Such pointers are used by rust-analyzer all
other the place to record relationships between IR nodes and the
original syntax.
Internally, the pointer to a syntax node is represented by node's range.
To "dereference" the pointer, you traverse the syntax tree from the
root, looking for the node with the right range. The inner loop of this
search is finding a node's child whose range contains the specified
range. This inner loop was implemented by naive linear search over all
the children. For wide trees, dereferencing a single `SyntaxNodePtr` was
linear. The problem with wide trees though is that they contain a lot of
nodes! And dereferencing pointers to all the nodes is quadratic in the
size of the file!
The solution to this problem is to speed up the children search --
rather than doing a linear lookup, we can use binary search to locate
the child with the desired interval.
Doing this optimization was one of the motivations (or rather, side
effects) of #6857. That's why `rowan` grew the useful
`child_or_token_at_range` method which does exactly this binary search.
But looks like we've never actually switch to this method? Oups.
Lesson learned: do not leave broken windows in the fundamental infra.
Otherwise, you'll have to repeatedly re-investigate the issue, by
digging from the top of the Everest down to the foundation!
[1]: https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/.60syntax_highlighting_not_quadratic.60.20failure/near/240811501
[2]: https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/Syntax.20highlighting.20is.20quadratic
[3]: https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/Syntax.20highlighting.20is.20quadratic/near/243412392
9080: Improve completion of cfg attributes r=JamieCunliffe a=JamieCunliffe
This will close#5398 and it also adds some completion for cfg options.
Co-authored-by: Jamie Cunliffe <Jamie.Cunliffe@outlook.com>
The completion of cfg will look at the enabled cfg keys when
performing completion.
It will also look crate features when completing a feature cfg
option. A fixed list of known values for some cfg options are
provided.
For unknown keys it will look at the enabled values for that cfg key,
which means that completion will only show enabled options for those.
9264: feat: Make documentation on hover configurable r=Veykril a=Veykril
This also implements deprecation support for config options as this renames `hoverActions_linksInHover` to `hover_linksInHover`.
Fixes#9232
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>
9227: Add a config setting to disable the 'test' cfg in specified crates r=matklad a=lf-
If you are opening libcore from rust-lang/rust as opposed to e.g.
goto definition from some other crate which would use the sysroot
instance of libcore, a `#![cfg(not(test))]` would previously have made
all the code excluded from the module tree, breaking the editor
experience.
Core does not need to ever be edited with `#[cfg(test)]` enabled,
as the tests are in another crate.
This PR puts in a slight hack that checks for the crate name "core" and
turns off `#[cfg(test)]` for that crate.
Fixes#9203Fixes#9226
Co-authored-by: Jade <software@lfcode.ca>
9357: fix: Update sysroot crates r=jonas-schievink a=jonas-schievink
Removes `rtstartup`, since that's not a Cargo crate (its files are compiled into object files and linked alongside the stdlib).
Adds `std_detect`.
Part of https://github.com/rust-analyzer/rust-analyzer/issues/9352 (doesn't fix it since std_detect is full of `cfg_if!`)
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
9355: Don't insert `}` when typing `{` in string r=jonas-schievink a=jonas-schievink
Checks that the token at the cursor is `L_CURLY`.
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/9351
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
9347: add note about passing cfg(debug_assertions) r=matklad a=rezural
add note about passing cfg(debug_assertions) to rustc on build. The server will not spin on start without this arcane hack
Co-authored-by: rezural <69941255+rezural@users.noreply.github.com>
9346: Refactor / clean up hir_ty tests r=flodiebold a=flodiebold
Notable changes:
- unify `check_types` and `check_mismatches` into `check`, which supports both kinds of annotations (`check_types` still exists because I didn't want to change all the annotations, but uses the same implementation)
- because of that, `check_types` now fails on any type mismatches; also annotations always have to hit the exact range
- there's also `check_no_mismatches` for when we explicitly just want to check that there are no type mismatches without giving any annotations (`check` will fail without annotations)
- test annotations can now be overlapping (they point to the nearest line that has actual code in that range):
```
// ^^^^ annotation
// ^^^^^^^^^ another annotation
```
Co-authored-by: Florian Diebold <flodiebold@gmail.com>
