On Sun, Feb 8, 2015 at 6:41 AM, Sven Barth <pascaldra...@googlemail.com> wrote:
> On 08.02.2015 04:10, silvioprog wrote: > >> Hello, >> >> I'm trying to port a Delphi code to FPC, and it has a structure like: >> >> TType = class(TObject) >> end; >> >> TTest<T1; T2: TType> = class(TObject) >> end; >> >> TFoo = class(TType) >> end; >> >> TBar = class(TTest<string, TFoo>) >> end; >> >> I.e., T1 accepts any type, but T2 accepts _only_ TType and/or their >> descendants. >> >> I tried the following code in FPC: >> >> TType = class(TObject) >> end; >> >> generic TTest<T1; T2: TType> = class(TObject) >> end; >> >> TFoo = class(TType) >> end; >> >> TBar = class(specialize TTest<string, TFoo>) >> end; >> >> But: >> >> === >> Compile Project, Target: project1.exe: Exit code 1, Errors: 2 >> Unit1.pas(30,34) Error: class type expected, but got "AnsiString" >> Unit1.pas(30,47) Error: class type expected, but got "<erroneous type>" >> === >> >> If I declare "T2" instead of "T2: TType", it compiles, but using this >> declaration, a programmer can use accidentally a non descendant type of >> TType. >> >> Is there an issue about this in bugtracker? >> > > Looks like a bug. Please report. > Done: http://bugs.freepascal.org/view.php?id=27424 > As a workaround you can move the constraint to the first type instead of > the second and specialize with "<TFoo, string>". > I'll try it. Thank you! (y) Regards, > Sven -- Silvio Clécio My public projects - github.com/silvioprog
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