private static @NotNull String getReasonForIncompatibleTypes(PsiType rType) {
    if (rType instanceof PsiMethodReferenceType) {
      JavaResolveResult[] results = ((PsiMethodReferenceType)rType).getExpression().multiResolve(false);
      if (results.length > 1) {
        PsiElement element1 = results[0].getElement();
        PsiElement element2 = results[1].getElement();
        if (element1 instanceof PsiMethod && element2 instanceof PsiMethod) {
          String candidate1 = format(element1);
          String candidate2 = format(element2);
          return JavaErrorBundle.message("incompatible.types.reason.ambiguous.method.reference", candidate1, candidate2);
        }
      }
    }
    return "";
  }
private static @NotNull String getReasonForIncompatibleTypes(PsiType rType)