A Roslyn analyzer which requires that classes be sealed, abstract, or attributed with
[Open].
Design and document for inheritance or else prohibit it
– Item 19, Effective Java, Third Edition
C# creates new types as open by default which can be dangerous. This analyzer ensures that the intent to leave a class open is explicitly declared.
using Nopen.NET.Attributes;
sealed class Foo {}
abstract class Bar {}
[Open] class Baz {}Non-sealed, non-abstract classes without the [Open] attribute will be marked with an error.
class Bad {}Bad.cs(1,1): error Nopen: Class 'Bad' is implicitly open. Classes should be explicitly marked sealed, abstract, or [Open].
For more information see Item 19 of Effective Java, Third Edition.
<ItemGroup>
<PackageReference Include="Nopen.NET" Version="<version_here>" PrivateAssets="All" />
</ItemGroup>Thanks to Jake Wharton and his Nope'n project for the idea.
Copyright 2019 Marius Volkhart
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