R#6: InstantHandleAttribute

Dear R# Team,

Thanks for the 6th major release - really enjoy the results of your work.

Have an issue with the InstantHandleAttribute: it would be nice to have a way to tell the engine (maybe through InstantHandleAttribute of via some NotInstantHandleAttribute) that the method which takes an IEnumerable as a parameter DOES NOT enumerate it.

Here is the reason:

I have a helper class Assure that validates my parameters via ValidateArgument<T> method:

  /// <summary>
  /// This class is a defensive programming helper class.
  /// It allows to validate objects (i.e. check for null etc.)
  /// as well as to check other conditions to prevent unnecessary
  /// exceptions.
  /// </summary>
  public static class Assure
    /// <summary>
    /// Checks if passed Value is non-empty
    /// if not - throws either ArgumentNullException or ArgumentException
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="inArgument">Value to be checked</param>
    /// <param name="inArgumentName">Argument name going to be a part of ArgumentNullException</param>
    /// <exception cref="System.ArgumentException">Thrown if passed value is empty</exception>
    public static void ValidateArgument<T>(
      [AssertionCondition(AssertionConditionType.IS_NOT_NULL)] T inArgument,
      [InvokerParameterName] String inArgumentName) where T : class
      if (inArgument != null)

      String tmpCallingMethodName = ExecutionStackHelper.GetMethodName(1);
      String tmpErrorMessage = String.Format(
        "{0}(): Object argument {1} is empty", tmpCallingMethodName, inArgumentName);
      throw new ArgumentException(
        String.Format("{0}(): Object argument is empty", tmpCallingMethodName), inArgumentName);

If I use it against enumerable arguments, for example:

    protected override void DoOnInsertRange(Int32 inIndex, IEnumerable<T> inItems)
      Assure.ValidateArgument(inItems, "inItems");

      foreach (T tmpItem in inItems)

I get the "Possible multiple enumerations of IEnumerable" error.
Looks like the engine got confused by Assure.ValidateArgument(inItems, "inItems") call - it thinks I iterate there.

I understand that I could have used the [NotNull] on the inItems parameter itself, but the Assure class is used everywhere - can't really make such a global change.

Also, the ValidateArgument<T> could be made non-generic, but in this case it's possible to call it on value types - don't want to lose that.

What would you suggest as a solution?



1 comment
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Hello Phil,

Thank you for feedback! I've logged this as a feature request: http://youtrack.jetbrains.net/issue/RSRP-273689
and you're welcome to montor its status.

Andrey Serebryansky
Senior Support Engineer
JetBrains, Inc
"Develop with pleasure!"



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