Declaration is deemed incompatibile

Question

Straight to the point:

I have an abstract class called Chart<IType> with child CandlestickChart<CandlestickChartItem> etc.
... an abstract class called ChartItem with child CandlestickChartItem etc.
... an abstract class called ChartSelection with child CandlestickChartSelection etc.

Relevant piece of code:

/* --- CHARTS --- */
template <typename IType>
class Chart {
    ...
    typedef std::vector<IType> ChartData;
}

class CandlestickChart :
    public Chart<CandlestickChartItem> { }

/* --- CHART SELECTIONS --- */
template <typename ChartType>
class ChartSelection {
    ...
    virtual ChartType::ChartData::const_iterator findStart() = 0;
};

class CandlestickChartSelection : public ChartSelection<CandlestickChart> {
    ...
    CandlestickChart::ChartData::const_iterator findStart() override;
};

How compiler feels about this:

Error   C2253   'ChartSelection<CandlestickChart>::findStart':
    pure specifier or abstract override specifier only allowed on virtual function
Error   C3668   'CandlestickChartSelection::findStart':
    method with override specifier 'override' did not override any base class methods

TL;DR: Why does my compiler think that the method findStart in the child class is different from the virtual function in the parent class? Is there a simple way to solve this?

I'm guessing uninstalling MSVC and installing MinGW might be a bit un-simple — Passer By, Jun 08 '17 at 16:10
@tobi303 Ok :) But are they really distinct? `ChartType::ChartData::const_iterator` and `ChartType::ChartData::const_iterator` look the same to me. — user35443, Jun 08 '17 at 16:12
@PasserBy, sorry, I don't understand - is this a MSVC specific thing? — user35443, Jun 08 '17 at 16:12
@user35443 Apparently, yes. MSVC has some of the best error messages. [Check this](http://cpp.sh/9gel3) — Passer By, Jun 08 '17 at 16:14
@JohannesSchaub-litb got it, thank you :) You can post it as an answer. Just, why is the typename there necessary? — user35443, Jun 08 '17 at 16:17
[Where and why do I have to put the “template” and “typename” keywords?](https://stackoverflow.com/questions/610245/where-and-why-do-i-have-to-put-the-template-and-typename-keywords) — Passer By, Jun 08 '17 at 16:19
@JohannesSchaub-litb ok, I see you were kidding me :P The g++ error message says it all :D — user35443, Jun 08 '17 at 16:20

Declaration is deemed incompatibile

0 Answers0