[Meta] Support Inline Completions related features.

[Kingwl]

Suggestion

🔍 Search Terms

inline, completions

✅ Viability Checklist

My suggestion meets these guidelines:

• [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code
• [x] This wouldn't change the runtime behavior of existing JavaScript code
• [x] This could be implemented without emitting different JS based on the types of the expressions
• [x] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• [x] This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

VScode has supported inline completions: https://github.com/microsoft/vscode/blob/main/src/vs/vscode.proposed.d.ts#L2576.

Let's find out what can we do with the new API.

[Kingwl]

I guess we could ping @mjbvz .

[Kingwl]

I think we should add the support even we do not have some feature yet.

I want to provide some inline completions by my ts plugin. But there's no way to do that without the ts support.

We have already supported custom events hander for plugin. But we also have to support the inline completion at the vscode side.

So, friendly ping @mjbvz , Shall we add the inline completion support at typescript vscode extension without typescript's implementation? If not. I think we should add the protocol first, and we can just return empty response.

[andrewbranch]

What are inline completions?

[mjbvz]

Here's the proposed VS Code api: https://github.com/microsoft/vscode/issues/124024 and https://github.com/microsoft/vscode/blob/019867139e8818908d65c814816acc3119c5dd1f/src/vs/vscode.proposed.d.ts#L2456

I believe Copilot uses them shows an inline preview of the suggested text while still letting you use normal completions

I think we should hold off on merging anything until the VS Code side of this api is finalized. There are a few open questions with the existing proposal