Auto-completion in list literals strips delimiters away.

[j-em]

Description

Triggering auto-completion on an identifier that is preceded by [ removes the [ itself on candidate insertion.

Repro steps

1. Type in the following code.

type Animal = Dog | Cat

let animals = [Do//<- cursor is here

2. Trigger company-complete while cursor is right after [Do

3. Select the Dog candidate in company UI.

Expected behavior

Do gets auto-completed to Dog while the leading [ stays intact.

Code before auto-completion

type Animal = Dog | Cat
let animals = [Do

Code after auto-completion

type Animal = Dog | Cat 
let animals = [Dog

Actual behavior

Do gets auto-completed to Dog while the leading [ is stripped away.

Code before auto-completion

type Animal = Dog | Cat
let animals = [Do

Code after auto-completion

type Animal = Dog | Cat
let animals = Dog

Known workarounds

Inserting a space between the opening bracket and the first element of the list makes the auto-completion work properly again.

Related information

• Ubuntu 16.04 LTS
• Emacs 24.5.1 & Emacs 27.0.50 (Tested on both)
• Mono 5.10 & .NET Core 2.0.3

[juergenhoetzel]

Confirmed, cause: (fsharp-ac-get-prefix) return mistakenly [Do in this case.