"The import #date matches no exports" error in dataflow

[magnus_b]

Last night one of my dataflows suddenly stopped working, throwing the following error:
Expression.Error: The import #date matches no exports. Did you miss a module reference?

I found that the error came from a step where a custom column is created using the #date formula. Somehow the script was changed from:

#date(2020,1,1)

to

#"#date"(2020,1,1)

I tried changing it back to #date(2020,1,1), but I still get the same error. I also tried creating a new query to see if I could reproduce the issue, and I got the same error. In short, it seems I am unable to to use the #date function in Dataflows at all.

Since the issue appeared overnight, with no changes having been made to the dataflow recently, it leads me to believe this might be a bug in Dataflows?

I use this very simple query to reproduce the issue:

let
  Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlSKjQUA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Column 1" = _t]),
  #"Added custom" = Table.AddColumn(Source, "date", each #date(2020, 1, 1))
in
  #"Added custom"

[tez · Accepted solution]

Apparently corrected: For a few hours, my dataflow has been working again without errors, without any intervention on my part.

[Anonymous]

I've had exactly the same issue as mentioned here. The power query editor will continually change the line back from #date to #"#date"- feels like a really annoying error that should have been caught by a proper testing stage. Presumably this is affecting anyone trying to use '#date' in a data set.

For anyone facing this issue, the workaround that worked for me (as Veles) point to, changing this section:

#date(Number.ToText([FY], 4, 1)

to this:

Date.FromText(Text.Combine({Number.ToText([FY]), "-04-01"})

[MarioVW]

I've been having exactly the same issue over here. Several dataflows across three different tenants. I already opened a support case with Microsoft, will let you know what they tell me.

[Veles]

I get exactly the same issue. Dataflow I made a few days ago has suddenly stopped working. Looked through the code and it had changed a #date(...) function to #"#date"(...) and was thinking it was a reference to a step in a query that didn't exist.

I did a workaround using the Date.FromText() function but annoying that there has clearly been a back end change that is breaking peoples' queries even though the code is correct.