Using PreFast internally we recently came across a class of bugs. In several places we were using uninitialized structures as local variables. The error came about because the types in question had no default constructor. For instance take the following structure

While playing around with a batch of Orcas code recently I found a welcome change to the C# type inference rules for Orcas. The return type of a generic delegate can now be inferred from the actual return values. Here is some sample code demonstrating the problem.

For previous articles in this series please see …

When investigating bugs a lot of times you start out with an unfamiliar HRESULT value. Searching the web will give you a hint of what the problem is and the real search can begin. If you get this error out of a log file it can come in a base 10 value versus a base 16 (hex). Searching for your base 10 code is much less efficient that the hex counter part. No matter.

The new version of the Visual Studio 2008 Beta2 SDK was just released. Among the many new samples is a basic expression evaluator sample. This sample shows you how to add basic debugger support to a managed language in Visual Studio.