private @NotNull PsiSubstitutor mapSubstitutor(PsiClass originalClass, PsiClass mappedClass, PsiSubstitutor substitutor) {
    PsiTypeParameter[] typeParameters = mappedClass.getTypeParameters();
    PsiTypeParameter[] originalTypeParameters = originalClass.getTypeParameters();
    if (typeParameters.length != originalTypeParameters.length) {
      if (originalTypeParameters.length == 0) {
        return JavaPsiFacade.getElementFactory(mappedClass.getProject()).createRawSubstitutor(mappedClass);
      }
      return substitutor;
    }

    Map<PsiTypeParameter, PsiType> substitutionMap = substitutor.getSubstitutionMap();

    PsiSubstitutor mappedSubstitutor = PsiSubstitutor.EMPTY;
    for (int i = 0; i < originalTypeParameters.length; i++) {
      if (!substitutionMap.containsKey(originalTypeParameters[i])) continue;

      PsiType originalSubstitute = substitutor.substitute(originalTypeParameters[i]);
      if (originalSubstitute != null) {
        PsiType substitute = mapType(originalSubstitute);
        if (substitute == null) return substitutor;

        mappedSubstitutor = mappedSubstitutor.put(typeParameters[i], substitute);
      }
      else {
        mappedSubstitutor = mappedSubstitutor.put(typeParameters[i], null);
      }
    }

    if (mappedClass.hasModifierProperty(PsiModifier.STATIC)) {
      return mappedSubstitutor;
    }
    PsiClass mappedContaining = mappedClass.getContainingClass();
    PsiClass originalContaining = originalClass.getContainingClass();
    //noinspection DoubleNegation
    if ((mappedContaining != null) != (originalContaining != null)) {
      return substitutor;
    }

    if (mappedContaining != null) {
      return mappedSubstitutor.putAll(mapSubstitutor(originalContaining, mappedContaining, substitutor));
    }

    return mappedSubstitutor;
  }
private @NotNull PsiSubstitutor mapSubstitutor(PsiClass originalClass, PsiClass mappedClass, PsiSubstitutor substitutor)