PVS-Studio warning V599 for TPP

class DiscriminantFunction {
public:
  DiscriminantFunction(int charge);
  virtual Boolean isComputable(SearchResult* result) = 0;
  virtual double getDiscriminantScore(SearchResult* result) = 0;
  virtual void error(int charge);
protected:
  int charge_;
  double const_;
}; // class

class CometDiscrimFunction : public DiscriminantFunction;
class CruxDiscrimFunction : public DiscriminantFunction;
class InspectDiscrimFunction : public DiscriminantFunction;
.....

class DiscrimValMixtureDistr : public MixtureDistr {
  ....
  DiscriminantFunction* discrim_func_;
  ....
};

DiscrimValMixtureDistr::~DiscrimValMixtureDistr() {
  delete[] posinit_;
  delete[] neginit_;
  delete discrim_func_;
}

This suspicious code was found in TPP project by PVS-Studio static code analyzer.
Warning message is:
V599 The virtual destructor is not present, although the 'DiscriminantFunction' class contains virtual functions. discrimvalmixturedistr.cxx 206

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