PsiSubstitutor getInstantiations(Collection<InferenceVariable> variables) {
    PsiSubstitutor substitutor = PsiSubstitutor.EMPTY;
    for (InferenceVariable variable : variables) {
      final PsiType equalsBound = getEqualsBound(variable, substitutor);
      if (equalsBound != null && !PsiTypes.nullType().equals(equalsBound)) {
        substitutor = substitutor.put(variable.getParameter(), equalsBound);
      }
    }
    return substitutor;
  }
PsiSubstitutor getInstantiations(Collection<InferenceVariable> variables)