Failed to enter insert-mode if a snippet starts with a linked placeholder.

[fingershi]

To Reproduce

See this simple snippet:

	"test": {
		"prefix": "test",
		"body": [
			"${1:some_placeholder}, $1" 
		],
	},

After typing "test" and expanded, vim enters visual mode instead of insert mode.

The bug occurs only if all 3 conditions below are met:

1. The snippet must start with a placeholder. "blah blah ${1:some_placeholder} $1" works fine.
2. The placeholder must be linked. "${1:some_placeholder} blah blah" works fine.
3. It should be a placeholder, not a simple tabstop. "$1 blah blah $1" works fine.

Environment (please complete the following information):

• Extension (VsCodeVim) version: 1.18.5
• VSCode version: 1.52.1
• OS: win10

[vdegenne]

I have the exact same bug with an even simpler snippet for testing :

${1:foo}${2:bar}

In other words the bug is not related to "linked placeholders" as you thought.
Rather I think it's when there is no space after the closing bracket of a placeholder.
If the placeholder is ${1:foo} ${2:bar} it works just fine, just like in your examples.

version: 1.19.0

note: Have you find a workaround @fingershi ?

[vdegenne]

I think one way to fix that would be to add a command in this file, but I am not sure how things work:

https://github.com/VSCodeVim/Vim/blob/5a2dc0210df86cff80f1c6be559316d50e40191c/src/actions/commands/insert.ts

Maybe add a command on <Tab> in Mode.Insert and it should check if the editor is not editing snippet, and if it is it should prevent to switch in Visual Mode, is it possible ?

@J-Fields @Chillee @jbaiter @jpoon @xconverge @fatanugraha @cvaldev @shawnaxsom @lyup @ldm0 @kylecarbs

[J-Fields]

We're not sure how to handle <Tab> in insert mode currently, see #5131