Left join entity is never null

Không có tệp mã nguồn hoặc bài kiểm thử nào được nêu. Hãy bắt đầu bằng cách tái hiện cả hai dạng truy vấn trong issue với SQLProvider v1.1.93, tập trung vào leftOuterJoin, DefaultIfEmpty() và entity có giá trị mặc định được báo cáo. Hoàn thành khi cú pháp được hỗ trợ và hành vi mong đợi khi thiếu entity được ghi lại hoặc kiểm thử.

Describe the bug
I am trying to left join "sheets" entity but I can't get it to work properly.

The documentation says that leftOuterJoin is not supported, but I see examples on stackoverflow of people saying this works.
For me it does not.

query {
        for e in ctx.Dbo.TimeEntries do
        join t in ctx.Dbo.ProjectTasks on (e.TaskId = t.Id)
        leftOuterJoin sheet in ctx.Dbo.DrawingLogSheets on (e.SheetId = Some sheet.Id) into sheetResults
        for s in sheetResults.DefaultIfEmpty() do
        where (e.Email = Some email && e.Date = dateOnly)
        select (toTimeEntry(e, t, s))
    }

This fails with an error.

I also tried this approach:

query {
        for e in ctx.Dbo.TimeEntries do
        join t in ctx.Dbo.ProjectTasks on (e.TaskId = t.Id)
        join s in (!!) ctx.Dbo.DrawingLogSheets on (e.SheetId = Some s.Id)
        where (e.Email = Some email && e.Date = dateOnly)
        select (toTimeEntry(e, t, s))
    }

This kind of works, but sheet is never null when it is missing; instead, it has all its values defaulted. For example, its ID field is a new guid (all zeros), and its string values are all empty string. I suppose I could check for defaulted guid, but this just feels like something is not right.

To Reproduce

Expected behavior
In the first example (leftOuterJoin), I just want to verify whether this syntax is supposed to be supported or not.
In the second example (!!), I would expect the sheet entity to be null when no sheet is joined, but instead it is instantiated with all default values.

Screenshots

Desktop (please complete the following information):

• Windows
• SQLProvider is v1.1.93

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.