Add generic constraint for non-abstract (and abstract)

[zorgoz]

Before required property modifier was added to the language, the constraint new() was practically equivalent to a non-abstract constraint. But currently there is no combination constraints equivalent to restriction to non-abstract types that may have required properties.

Suggested keywords: concrete and abstract.

• abstract and new() are mutually exclusive
• the new constraints cannot be combined with struct

[huoyaoyuan]

Generic constraints provided by the language enables additional operations under the constraint. Constraints that doesn't enable operation but purely limiting usages should be provided by analyzers.

[Joe4evr]

I even made one like that. I just haven't had the time to improve it more.

[zorgoz]

That's nice. Thanks for the hint. Joe4evr ***@***.***> ezt írta (időpont: 2024. aug. 27., K, 11:14):

…

I even made one like that. <https://github.com/Joe4evr/JiiLib/blob/master/src/JiiLib.Constraints/Analyzers/NonAbstractOnly/NonAbstractConstraintAnalyzer.cs> I just haven't had the time to improve it more. — Reply to this email directly, view it on GitHub <#8391 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAL7DEUXGIBVUECS7H2LP33ZTQ7N3AVCNFSM6AAAAABNEDBVECVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTANBWGA4TAOI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[TahirAhmadov]

You can also do a static ctor to check it at runtime:

class Foo<T>
{
  static Foo()
  {
    if(typeof(T).IsAbstract) throw new Exception("Type T cannot be abstract");
  }
}

[zorgoz]

I know that, but for my purposes a design-time approach is way better. I suppose I will go with analyzers as I have way more things to check. Mr. TA ***@***.***> ezt írta (időpont: 2024. aug. 27., K, 19:29):

…

You can also do a static ctor to check it at runtime: class Foo<T>{ static Foo() { if(typeof(T).IsAbstract) throw new Exception("Type T cannot be abstract"); }} — Reply to this email directly, view it on GitHub <#8391 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAL7DEWBU4U54WATE472BD3ZTSZQ3AVCNFSM6AAAAABNEDBVECVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTANBWGYYDKMQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>