Create `.vscode` directory in `x.py setup`

[jyn514]

Right now, .vscode needs to be configured anew for each workspace and person working on the compiler. We do document the recommended settings in https://rustc-dev-guide.rust-lang.org/building/suggested.html#configuring-rust-analyzer-for-rustc, but it's annoying to have to copy-paste it each time. It would be nice if x setup created those files for you automatically.

Ideally we would even version the config (maybe with a stamp file so it's not in the settings.json file itself) and suggest rerunning x setup in tidy if the config in .vscode gets outdated.

cc https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/False.20error.20report.20for.20.60rust-analyzer.28private-field.29.60 - it might be the case that the settings vary depending on the part of the compiler you're working on? I would really hate for that to be the case, but having per-profile .vscode setup might be one way to make it less painful :/

[jyn514]

I also considered checking .vscode into git, but that doesn't allow people to modify it locally, and doesn't allow the config to be different depending on the profile.

[thomcc]

I think this is fine so long as x setup prompts the user asking if they want this, with options for yes/no/print, where print just dumps the settings json it wants to add to stdout or whatever.

And probably if .vscode/settings.json already exists you should just always print instead of trying to modify it in-place (modifying sounds hard since that file allows comments, and i would be pretty mad if they got overwritten).

[jyn514]

👍 sounds good - we do something like that today for the pre-push hook:

rust/src/bootstrap/setup.rs

Lines 375 to 389 in 4aa6afa

	let should_install = loop {
	print!("Would you like to install the git hook?: [y/N] ");
	io::stdout().flush()?;
	input.clear();
	io::stdin().read_line(&mut input)?;
	break match input.trim().to_lowercase().as_str() {
	"y" | "yes" => true,
	"n" | "no" | "" => false,
	_ => {
	eprintln!("error: unrecognized option '{}'", input.trim());
	eprintln!("note: press Ctrl+C to exit");
	continue;
	}
	};
	};

[jyn514]

Prior art: https://github.com/rust-lang/rust-clippy/blob/8a9860901f0ae9782ff23fb793838a16f733a60b/clippy_dev/src/setup/vscode.rs