c# code seems to get optimized in an invalid way such that an object value becomes null

Question

I have the following code that exhibits a strange problem:

var all = new FeatureService().FindAll();
System.Diagnostics.Debug.Assert(all != null, \"FindAll must          


        

Answer 1

After Lasse discovered that the FindAll method was generating the wrong IL, I then came across another method that was also generating the wrong IL -- I also found the root cause and resolution.

The relevant line in the second method is:

var policy = Cache.GetDefaultCacheItemPolicy(dependentKeys, true);

Cache is my own object. The GetDefaultCacheItemPolicy method returns a System.Runtime.Caching.CacheItemPolicy object. The generated IL, however, looked like this:

Func policy = (Func) base.Cache.GetDefaultCacheItemPolicy(dependentKeys, true);

There are two projects in play here. The methods that are generating the wrong IL are in one project called DomainModel, and the Cache object is in a Utilities project, which is referenced by the first. The second project contains a reference to System.Runtime.Caching but the first does not.

The fix was to add a reference to System.Runtime.Caching to the first project. Now the generated IL looks correct:

CacheItemPolicy policy = base.Cache.GetDefaultCacheItemPolicy(dependentKeys, true);

The first method (that Lasse posted about in his answer) now also generates proper IL.

Hooray!