With the release of CLR 4 being so close, we’ve been working hard on getting the new C# and VB language features implemented inside Reflector. The work isn’t complete yet, but we have some of the features working. Most importantly, there are going to be changes to the Reflector object model, and we though it would be useful for people to see the changes and have an opportunity to comment on them.

Before going any further, we should tell you what the EAP contains that’s different from the released version.

A number of bugs have been fixed, mainly bugs that were raised via the forum. This is slightly offset by the fact that this EAP hasn’t had a whole lot of testing and there may have been new bugs introduced during the development work we’ve been doing.

The C# language writer has been changed to display in and out co- and contra-variance markers on interfaces and delegates, and to display default values for optional parameters in method definitions. We also concisely display values passed by reference into COM calls. However, we do not change callsites to display calls using named parameters; this looks like hard work to get right.

The forthcoming version of the C# language introduces dynamic types and dynamic calls. The new version of Reflector should display a dynamic call rather than the generated C#:

We have a few bugs in this area where we are not casting to dynamic when necessary. These have been fixed on a branch and should make their way into the next EAP.

To support the dynamic features, we’ve added the types IDynamicMethodReferenceExpression, IDynamicPropertyIndexerExpression, and IDynamicPropertyReferenceExpression to the object model. These types, based on the versions without “Dynamic” in the name, reflect the fact that we don’t have full information about the method that is going to be called, but only have its name (as a string). These interfaces are going to change – in an internal version, they have been extended to include information about which parameter positions use runtime types and which use compile time types. There’s also the interface, IDynamicVariableDeclaration, that can be used to determine if a particular variable is used at dynamic call sites as a target.

A couple of these language changes have also been added to the Visual Basic language writer.

The new features are exposed only when the optimization level is set to .NET 4. When the level is set this high, the other standard language writers will simply display a message to say that they do not handle such an optimization level. Reflector Pro now has 4.0 as an optional compilation target and we have done some work to get the pdb generation right for these new features.

The EAP version of Reflector no longer installs the add-in on startup. The first time you run the EAP, it displays the integration options dialog. You can use the checkboxes to select the versions of Visual Studio into which you want to install the EAP version. Note that you can only have one version of Reflector Pro installed in Visual Studio; if you install into a Visual Studio that has another version installed, the previous version will be removed.

Please try it out and send your feedback to the EAP forum.