...

src/Syntax/Typing/NubType.cs

@@ -43,6 +43,8 @@ public abstract class NubType
 
     public bool IsNumber => IsFloat32 || IsFloat64 || IsInteger;
 
+    public bool IsVoid => this is NubVoidType;
+
     public abstract override bool Equals(object? obj);
     public abstract override int GetHashCode();
     public abstract override string ToString();