boolean (@NotNull GrSignature signature, final int argCount) { if (argCount > 0 || signature.isCurried()) return false; final GrClosureParameter[] parameters = signature.getParameters(); if (parameters.length != 1) return false; final PsiType type = parameters[0].getType(); return InheritanceUtil.isInheritor(type, CommonClassNames.JAVA_UTIL_MAP); }