Delphi generic nested classes
Posted by jpluimers on 2019/08/21
Reminder to Self: do not nest T generic types as you’re in for a surprise.
Source: [WayBack] Delphi generic nested classes
Via: [WayBack] An interesting question over on SO relating to nested generic classes… – David Heffernan – Google+
The surprise:
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| type | |
| TClassC<T> = class | |
| private | |
| type | |
| TClassD<T> = class | |
| private | |
| x: T; | |
| end; | |
| end; | |
| var | |
| obj: TClassC<Integer>.TClassD<string>; |
what type would you expect obj.x to be? Integer or string?
The compiler hint:
[dcc32 Hint]: H2509 Identifier 'T' conflicts with type parameters of container type
–jeroen
The Wiert Corner - irregular stream of stuff 
Sebastian Jänicke said
I did not try it yet, but I would expect it to be of type Integer. This would be the only logical way as T is already defined when you get to the inner class. So there should be no way to redeclare this type. I would be very surprised, if this would be different.
Sebastian Jänicke said
I would have expected a compiler error to be honest (redeclared type or something like this).