VB -> C#: error CS8122 when using is null instead of == null

[CardenInsurance]

My actual VB.Net code is a complicated LINQ query that gets error CS8122 on a part that says Where (pd.Record_Type Is Nothing Or pd.Record_Type = "Acreage") and gets converted to where (pd.Record_Type is null | pd.Record_Type == "Acreage") but here is some code that might be easier to reproduce:

VB.Net input code

Dim x As Object = Nothing
Dim expression As System.Linq.Expression(Of Func(Of Boolean)) = Function() x Is Nothing

Erroneous output

object x = null;
System.Linq.Expressions.Expression<Func<bool>> expression = () => x is null; // CS8122

Visual Studio error:
CS8122 An expression tree may not contain an 'is' pattern-matching operator.

Expected output (replace "is" with "==")

object x = null;
System.Linq.Expressions.Expression<Func<bool>> expression = () => x == null; // fine

Details

• Product in use: e.g. VS extension
• Version in use: 9.0.2.0

[GrahamTheCoder]

Nice repro. Should be possible to check the surrounding expression types. For performance reasons we'll probably want to track when entering an expression so it's easy to check.

[Yozer]

Related: #316
Might be helpful to catch some corner cases:
https://github.com/JosefPihrt/Roslynator/blob/7ba2f29f5090aa13f4dd6b7936af55180b678333/src/CSharp/CSharp/Extensions/SyntaxExtensions.cs#L3114

[GrahamTheCoder]

Nice one 😊 Very handy method to use there!