The recent release of JetBrains' Rider IDE (EAP17) saw the removal of .NET Core debugging support. The removal was necessitated due to a licensing conflict with one of the NuGet packages used to provide debugging for .NET Core projects. In a relatively quick turnaround, JetBrains has produced Rider EAP18 which brings .NET Core debugging support back.
It took JetBrains just over a week to return this support, but it should be noted that presently .NET Core code can only be debugged on Windows systems, with support for debugging .NET Core on Linux and Mac OS X systems coming at a future date. JetBrains' Maarten Balliauw writes that this support includes the ability inspect variables and step through code, as well as the ability to attach to a running CoreCLR process.
The change in .NET Core support isn’t the only change for EAP18, as support for adding COM references to a project has also been added. Several bugs have been corrected too, including a fix for the "invalid volume separator char" error and an issue where unused code foldings can fail to behave properly.
A full list of fixes is provided by JetBrains, and Rider EAP18 may be downloaded now for Windows, Mac OS X, and Linux.