Deadlock problems still exist in version 0.17

[Shuenhoy]

Try this code copied from https://github.com/gluon-lang/gluon/issues/842.

type Digit a =
    | One a
    | Two a a
    | Three a a a
    | Four a a a a

type Node b =
    | Node2 b b
    | Node3 b b b

type FingerTree c =
    | Empty
    | Single c
    | Deep (Digit c) (FingerTree (Node c)) (Digit c)

type View d =
    | Nil
    | View d (FingerTree d)

rec let viewl xs : FingerTree e -> View e =
    match xs with
    | Empty -> Nil
    | Single x -> View x Empty
    | Deep (One a) deeper suffix ->
        match viewl deeper with
        | View (Node2 b c) rest -> View a (Deep (Two b c) rest suffix)
        | View (Node3 b c d) rest -> View a (Deep (Three b c d) rest suffix)
        | Nil ->
            match suffix with
            | One w -> View a (Single w)
            | Two w x -> View a (Deep (One w) Empty (One x))
            | Three w x y -> View a (Deep (Two w x) Empty (One y))
            | Four w x y z -> View a (Deep (Three w x y) Empty (One z))
    | Deep (Two a b) deeper suffix -> View a (Deep (One b) deeper suffix)
    | Deep (Three a b c) deeper suffix -> View a (Deep (Two b c) deeper suffix)
    | Deep (Four a b c d) deeper suffix -> View a (Deep (Three b c d) deeper suffix)
viewl

Find this line type View d =, modify the d to a, save the file. If nothing happens, modify a back to d, save. Repeat this procedure for a few times and the LSP would lock up.

Based on the experiences of my attempts to find out the problems, this probably happens here:

https://github.com/gluon-lang/gluon_language-server/blob/5465972e5e41481accc8cb14ddef1b470cd1f7c8/src/diagnostics.rs#L340-L342

But I didn't find out who is blocking it.