feat(cmds): support snippet text edit

[fannheyward]

rust-lang/rust-analyzer#4494

@oblitum @TimoFreiberg can you guys test this? Maybe you need to download latest nightly release.

[TimoFreiberg]

I'll try it :)
Do I understand correctly that I don't need to change any config and that I only expect assists to still place the cursor in the correct place?

Findings:

• Generating a function in another module (mod foo; foo::bar()<|>;) generates the function in the current module instead. The latest release of coc-rust-analyzer correctly generates the function in foo.rs instead.

[TimoFreiberg]

Oh my, this fixes the "select the generated todo!()" part of rust-lang/rust-analyzer#3639 🎉

[oblitum]

For me, checking actions when cursor is over foo at:

fn main() {
    foo();
}

Gives Add function action, which when triggered, generates a stub like:

fn main() {
    foo();
}
fn foo() {
    todo!()
}

I can see from neovim statusline that after that I enter a coc snippet session, but it's not useful because my cursor is at the end of the code, and there's no placeholder to jump to.

[oblitum]

Happens with mini.vim as:

set runtimepath^=~/.vim/plugged/coc.nvim
colorscheme peachpuff
let mapleader = ' '
nmap <silent> <leader>cA <Plug>(coc-codeaction)
vmap <silent> <leader>cA <Plug>(coc-codeaction-selected)

[fannheyward]

@oblitum do you use the stable or nightly release? stable release will add function foo but without jumping into it. nightly release will bring you into the foo function, and select todo!() in snippet mode.

https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/dev/lsp-extensions.md#snippettextedit

[oblitum]

I've tested with this pull + rust-analyzer nightly 42dd0ce.

coc/extensions/coc-rust-analyzer-data
❯ ./rust-analyzer --version
rust-analyzer 42dd0ce

[fannheyward]

Yes, it's the latest nightly release. This snippet textEdit feature is new in rust-analyzer.

[fannheyward]

@TimoFreiberg how do you get Generating a function in another module action?

[TimoFreiberg]

By writing mod foo; in some rust file, when the foo.rs doesn't exist yet. Then just placing the cursor on foo and trigger (coc-codeaction)

[fannheyward]

@TimoFreiberg yes, this will trigger Create module action, create foo.rs file, but there is no generates the function, nothing in foo.rs.

[TimoFreiberg]

Oh shit, I misread.
In that example case, when foo.rs exists, writing foo::bar(); in the old file should offer to generate fn bar() { todo!() } in foo.rs.
It used to properly generate the function in foo.rs, but now it generates it in the same file where foo::bar(); was written.

[fannheyward]

@TimoFreiberg reproduced.

[fannheyward]

@TimoFreiberg Tested with VSCode + RA, will fail to generate function for this example case. rust-lang/rust-analyzer#4551

[oblitum]

Sorry folks but I couldn't make it work like expected on my side, even with this branch compiled and latest rust-analyzer nightly. Jump to place holder doesn't work. Now on latest coc.nvim things got a bit more non intuitive because it's not showing coc actions for current line anymore and actions for buffer by default, so to even make the create function action to show I have to use coc action with selection.

[fannheyward]

@oblitum yes, coc-codeaction was changed to buffer only, you can use coc-codeaction-line neoclide/coc.nvim@d792515

[fannheyward]

@TimoFreiberg make a fix for generating function issue

[TimoFreiberg]

Now the closing brace of the generated function gets selected instead of the todo!()

Expected:

fn foo() {
    |todo!()|
}

Actual:

fn foo() {
   todo!()
|}|

[oblitum]

This is the behavior I reported.