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#include <iostream>
using namespace std;
 
class FeaturesExample {};
class Example : public FeaturesExample {};
 
template<typename D, typename T>
class Base {
 public:
  virtual float getFloat(const T* ex) const = 0;
  float getFloat(const FeaturesExample& ex) const {
  	get(reinterpret_cast<T*>(&ex));
  }
  float (Base::*getFloatImplPtr_)(const FeaturesExample& ex) const;
  float getFloatImpl_(const FeaturesExample& ex) const {
  	return 0.0;
  }
};
 
class Derived : public Base<Derived, Example> {
 public:
  virtual float getFloatImpl(const Example* ex) override {
  	return 1.0;
  }
};
int main() {
	FeaturesExample ex;
	Derived derived;
	auto f = derived.getFloat(ex);
	std::cout << f << std::endl;
	return 0;
}

prog.cpp:22:17: error: ‘virtual float Derived::getFloatImpl(const Example*)’ marked ‘override’, but does not override
   virtual float getFloatImpl(const Example* ex) override {
                 ^~~~~~~~~~~~
prog.cpp: In function ‘int main()’:
prog.cpp:28:10: error: cannot declare variable ‘derived’ to be of abstract type ‘Derived’
  Derived derived;
          ^~~~~~~
prog.cpp:20:7: note:   because the following virtual functions are pure within ‘Derived’:
 class Derived : public Base<Derived, Example> {
       ^~~~~~~
prog.cpp:10:17: note: 	float Base<D, T>::getFloat(const T*) const [with D = Derived; T = Example]
   virtual float getFloat(const T* ex) const = 0;
                 ^~~~~~~~
prog.cpp: In instantiation of ‘float Base<D, T>::getFloat(const FeaturesExample&) const [with D = Derived; T = Example]’:
prog.cpp:29:30:   required from here
prog.cpp:12:8: error: reinterpret_cast from type ‘const FeaturesExample*’ to type ‘Example*’ casts away qualifiers
    get(reinterpret_cast<T*>(&ex));
        ^~~~~~~~~~~~~~~~~~~~~~~~~
prog.cpp:12:7: error: ‘get’ was not declared in this scope
    get(reinterpret_cast<T*>(&ex));
    ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Standard output is empty