private static @NotNull LookupElement expressionToLookupElement(@NotNull PsiExpression expression) {
    if (expression instanceof PsiReferenceExpression refExpr && !refExpr.isQualified() && refExpr.resolve() instanceof PsiVariable var) {
      final VariableLookupItem item = new VariableLookupItem(var);
      item.setSubstitutor(PsiSubstitutor.EMPTY);
      return item;
    }
    if (expression instanceof PsiMethodCallExpression call && !call.getMethodExpression().isQualified()) {
      final PsiMethod method = call.resolveMethod();
      if (method != null) {
        return new JavaMethodCallElement(method);
      }
    }

    return new ExpressionLookupItem(expression);
  }
private static @NotNull LookupElement expressionToLookupElement(@NotNull PsiExpression expression)