boolean (Collection<PsiType> psiTypes, ProblemSink problemSink) { boolean result = true; for (PsiType psiType : psiTypes) { if (!checkConcreteClass(psiType)) { problemSink.addErrorMessage("inspection.message.delegate.can.only.use.concrete.class.types", psiType.getCanonicalText()); result = false; } else { result &= validateRecursion(psiType, problemSink); } } return result; }