On 16 June 2017 at 22:44, Georgios Petasis via gcc-help
<gcc-help@xxxxxxxxxxx> wrote:
> Hi all,
>
> I am trying to compile the following code, I am getting an error, and I am
> unable to fix the error.
>
> I am trying to compile this:
>
> template<typename Pattern>
> class HasAttributeMatchingValue: public
> AnnotationUnaryPredicateWithStates<std::string, Pattern> {
> bool operator() (const ELEP::CDM::Annotation& ann) const {
> return ann.containsAttributeMatchingValue(std::get<0>(m_state),
> std::get<1>(m_state));
> };
> };
>
> The error I am getting is:
>
> `m_state` was not declared in this scope: return
> ann.containsAttributeMatchingValue(std::get<0>(m_state),
> std::get<1>(m_state));
>
> If I use instead:
>
> template<typename Pattern>
> class HasAttributeMatchingValue: public
> AnnotationUnaryPredicateWithStates<std::string, std::string> {
> bool operator() (const ELEP::CDM::Annotation& ann) const {
> return ann.containsAttributeMatchingValue(std::get<0>(m_state),
> std::get<1>(m_state));
> };
> };
>
> It compiles without problem.
>
> AnnotationUnaryPredicateWithStates is a template:
>
> template<class... States> class AnnotationUnaryPredicateWithStates :
> public UnaryPredicateWithStates<ELEP::CDM::Annotation, States ... > {};
>
> template<class Arg, class... States> class UnaryPredicateWithStates :
> public UnaryFunctionWithStates<Arg, bool, States ... > {};
>
> template<class Arg, class Result, class... Ts>
> class UnaryFunctionWithStates : public UnaryFunction<Arg, Result> {
> public:
> UnaryFunctionWithStates() = default;
> template <class... Args> UnaryFunctionWithStates(Args&&... args) :
> m_state(std::forward<Args>(args)...) {};
> protected:
> std::tuple<Ts...> m_state;
> };
>
> template<class Arg, class Result> class UnaryFunction {
> public:
> virtual Result operator()(const Arg &) const = 0;
> };
>
> What am I doing wrong?
See https://gcc.gnu.org/wiki/VerboseDiagnostics#dependent_base
