Defining a function in one cell and calling it in another results in compilation error

[eerhardt]

Describe the bug

See the screen shot below.

I created a notebook, imported an assembly, defined a function that took a parameter of a type from that assembly in a cell. When I tried invoking the function in another cell I got a compilation error:

(2,6): error CS1503: Argument 1: cannot convert from 'Microsoft.ML.IDataView [/Users/eerhardt/.nuget/packages/microsoft.ml.dataview/1.2.0/lib/netstandard2.0/Microsoft.ML.DataView.dll]' to 'Microsoft.ML.IDataView [Microsoft.ML.DataView, Version=1.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51]'

Did this error occur while using dotnet try or online?

• dotnet-try
• online

What kind of error was it?

• User Interface (UI): For example the output never displayed
• Service Error: For example "The service is temporarily unavailable. We are working on it"
• Other:

Screenshots

If applicable, add screenshots to help explain your problem.

Please complete the following:

• OS
  • Windows 10
  • macOS
  • Linux (Please specify distro)
  • iOS
  • Android
• Browser
  • Chrome
  • Edge
  • Safari

[pgovind]

I just ran into this too. Here's what I was trying to do:

df is defined in the cells above(not included in the screenshot).

[svick]

I suspect this is the same issue as dotnet/roslyn#23123.

[eerhardt]

I believe we are going to need a fix for this issue before the notebook experience is a viable option for customers. Without this being fixed I can't imagine getting any real work done in a C# notebook.