Hello again

-
Hello again

I have this MCVE: http://pastebin.com/TsKZzyhF

Why are those interface types incompatible? With a hard-cast everything seems to go fine. Am I loosing something here?
http://pastebin.com/TsKZzyhF

Comments

  1. Agustin OrtuJanuary 11, 2017 at 7:51 PM

    For some odd reason I can't see this post if browsing from Delphi Developers community. I can only reach here if I navigate to my public G+ profile

    ReplyDelete
  2. Ondrej KelleJanuary 11, 2017 at 9:02 PM

    It's been flagged as spam for moderation, should be up now.

    ReplyDelete
  3. Christopher WosinskiJanuary 12, 2017 at 2:20 AM

    You are expecting "covariance" where you are not having it. Take a look here: delphisorcery.blogspot.de - Generics and variance and here: http://stackoverflow.com/questions/1687755/why-are-tgenericbase-and-tgenericdescendant-incompatible-types

    ReplyDelete
  4. Stefan GlienkeJanuary 12, 2017 at 2:28 AM

    Exactly what Christopher Wosinski said. In Delphi IGeneric is not compatible with IGeneric because for them to be compatible the T parameter would have to be declared as covariant

    ReplyDelete
  5. Agustin OrtuJanuary 12, 2017 at 3:13 AM

    Thank you guys

    ReplyDelete

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