[ty] Refactor inlay hints structure to use separate parts #20052

MatthewMckee4 · 2025-08-22T21:22:34Z

Summary

Our internal inlay hints structure (ty_ide::InlayHint) now more closely resembles lsp_types::InlayHint.

This mainly allows us to convert to lsp_types::InlayHint with less hassle, but it also allows us to manage the different parts of the inlay hint better, which in the future will allow us to implement features like goto on the type part of the type inlay hint.

It also really isn't important to store a specific Type instance in the InlayHintContent. So we remove this and use InlayHintLabel instead which just shows the representation of the type (along with other information).

We see a similar structure used in rust-analyzer too.

github-actions · 2025-08-22T21:24:25Z

Diagnostic diff on typing conformance tests

No changes detected when running ty on typing conformance tests ✅

MatthewMckee4 · 2025-08-22T21:30:27Z

crates/ty_server/tests/e2e/inlay_hints.rs

          "character": 1
        },
-        "label": ": Literal[1]",
+        "label": [


These change because we now use InlayHintLabel::LabelParts instead of InlayHintLabel::String

github-actions · 2025-08-22T21:30:34Z

`mypy_primer` results

No ecosystem changes detected ✅
No memory usage changes detected ✅

MatthewMckee4 · 2025-08-22T23:35:11Z

crates/ty_ide/src/inlay_hints.rs

+        let mut label = InlayHintLabel::simple(ty.display(db).to_string(), None);
+
+        label.prepend_str(": ");


This is roughly how rust analyzer does it and we need to separate these for the goto targets

MatthewMckee4 · 2025-08-22T23:36:44Z

crates/ty_ide/src/inlay_hints.rs

+
+#[derive(Debug, Clone)]
+pub struct InlayHintLabel {
+    pub parts: SmallVec<[InlayHintLabelPart; 1]>,


I think i should change this to 2. @MichaReiser would you agree?

ive done it, i think it makes sense for us.

ah okay in this situation we only use 1 of the InlayHintLabelPart, but when we add the goto, we will use 2.

I think it makes sense today because all our usages have exactly two parts. But it's hard to tell, depending on how you plan to use this going forward.

A too-large number has the downside that InlayHintLabel becomes larger overall, wasting memory when we only need to store 1 or more than two elements. This is especially problematic if we create many InlayHintLabels. I don't think this is a big concern here.

I'm not even sure if it's worth using a SmallVec here. We'll need to serialize all that data later on, we might as well just store a Vec

Currently because we don't use the target variable in InlayHintLabel. This means we just have one part so we will only use one of the elements in the small vec.

I'll change to vec for now anyway.

MichaReiser · 2025-08-23T12:33:29Z

Could you extend the summary? I think I've an idea why we may want this but I'd rather be sure (and documenting this will also help a future reader who comes across this PR and wonders why it works the way it does)

dhruvmanila · 2025-08-25T08:00:56Z

crates/ty_ide/src/inlay_hints.rs

+impl InlayHint {
+    pub fn type_hint(position: TextSize, ty: Type, db: &dyn Db) -> Self {


I think it'd be useful to add basic documentation for all the pub items in this module.

I'll try to make more things private

crates/ty_ide/src/inlay_hints.rs

dhruvmanila · 2025-08-25T08:05:40Z

crates/ty_ide/src/inlay_hints.rs

+        match &mut *self.parts {
+            [InlayHintLabelPart { text, target: None }, ..] => text.insert_str(0, s),
+            _ => self.parts.insert(


At first, I thought that the catch-all branch is for the empty vector ([]) but I don't think that's true, the branch that isn't covered here is an InlayHintLabelPart where target is Some. Can you expand on why does the string needs to be added only when navigation target is not present? Based on the method name, I would expect this to add the string regardless of whether target is present or not.

Ive just removed these methods, i think its better for us to just be more explicit with what the specific parts are anyway.

Is this because that would allow us to have the navigation target that is relevant for that specific part of the label? For example, in : Type, it's just the "Type" part that's possible to do go to definition.

crates/ty_ide/src/inlay_hints.rs

dhruvmanila · 2025-08-25T13:21:39Z

Feel free to re-request for review once it's ready.

MatthewMckee4 · 2025-08-25T15:26:46Z

could you re run that cargo test, looks like a flake

dhruvmanila

Thanks!

dhruvmanila · 2025-08-26T04:50:50Z

could you re run that cargo test, looks like a flake

I'm assuming that this was fixed?

* main: [`ruff`] Preserve relative whitespace in multi-line expressions (`RUF033`) (astral-sh#19647) [ty] Optimize TDD atom ordering (astral-sh#20098) [`airflow`] Extend `AIR311` and `AIR312` rules (astral-sh#20082) [ty] Preserve qualifiers when accessing attributes on unions/intersections (astral-sh#20114) [ty] Fix the inferred interface of specialized generic protocols (astral-sh#19866) [ty] Infer slightly more precise types for comprehensions (astral-sh#20111) [ty] Add more tests for protocols (astral-sh#20095) [ty] don't eagerly unpack aliases in user-authored unions (astral-sh#20055) [`flake8-use-pathlib`] Update links to the table showing the correspondence between `os` and `pathlib` (astral-sh#20103) [`flake8-use-pathlib`] Make `PTH100` fix unsafe because it can change behavior (astral-sh#20100) [`flake8-use-pathlib`] Delete unused `Rule::OsSymlink` enabled check (astral-sh#20099) [ty] Add search paths info to unresolved import diagnostics (astral-sh#20040) [`flake8-logging-format`] Add auto-fix for f-string logging calls (`G004`) (astral-sh#19303) Add a `ScopeKind` for the `__class__` cell (astral-sh#20048) Fix incorrect D413 links in docstrings convention FAQ (astral-sh#20089) [ty] Refactor inlay hints structure to use separate parts (astral-sh#20052)

…20052) ## Summary Our internal inlay hints structure (`ty_ide::InlayHint`) now more closely resembles `lsp_types::InlayHint`. This mainly allows us to convert to `lsp_types::InlayHint` with less hassle, but it also allows us to manage the different parts of the inlay hint better, which in the future will allow us to implement features like goto on the type part of the type inlay hint. It also really isn't important to store a specific `Type` instance in the `InlayHintContent`. So we remove this and use `InlayHintLabel` instead which just shows the representation of the type (along with other information). We see a similar structure used in rust-analyzer too.

Refactor inlay hints

3c50992

MatthewMckee4 marked this pull request as ready for review August 22, 2025 21:24

MatthewMckee4 requested review from AlexWaygood, MichaReiser, carljm, dcreager and sharkdp as code owners August 22, 2025 21:24

Fix clippy

a62519c

AlexWaygood removed their request for review August 22, 2025 21:26

MatthewMckee4 changed the title ~~Refactor inlay hints~~ [ty] Refactor ty_ide inlay hints Aug 22, 2025

MatthewMckee4 commented Aug 22, 2025

View reviewed changes

AlexWaygood added server Related to the LSP server ty Multi-file analysis & type inference labels Aug 22, 2025

carljm requested review from dhruvmanila and removed request for carljm August 22, 2025 23:12

MatthewMckee4 marked this pull request as draft August 22, 2025 23:17

Refactor InlayHintLabel

30e0d65

MatthewMckee4 commented Aug 22, 2025

View reviewed changes

Fix clippy

34fa907

MatthewMckee4 marked this pull request as ready for review August 22, 2025 23:43

Use Vec instead of SmallVec

2c4d400

dhruvmanila reviewed Aug 25, 2025

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dhruvmanila self-assigned this Aug 25, 2025

Clean up and resolve some review comments

d045e9c

Fix clippy

f6760d6

MatthewMckee4 requested a review from dhruvmanila August 25, 2025 15:26

MatthewMckee4 added 2 commits August 25, 2025 16:29

Small clean up

cb88f72

Small clean up

bc6292c

dhruvmanila added the internal An internal refactor or improvement label Aug 26, 2025

dhruvmanila changed the title ~~[ty] Refactor ty_ide inlay hints~~ [ty] Refactor inlay hints structure to use separate parts Aug 26, 2025

dhruvmanila approved these changes Aug 26, 2025

View reviewed changes

dhruvmanila merged commit 8d6dc7d into astral-sh:main Aug 26, 2025
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		let mut label = InlayHintLabel::simple(ty.display(db).to_string(), None);

		label.prepend_str(": ");

		impl InlayHint {
		pub fn type_hint(position: TextSize, ty: Type, db: &dyn Db) -> Self {

[ty] Refactor inlay hints structure to use separate parts #20052

[ty] Refactor inlay hints structure to use separate parts #20052

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MichaReiser commented Aug 23, 2025

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dhruvmanila commented Aug 25, 2025

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