ImportMany collection property has no setter, and it is always empty in the runtime.
I remember the bug #94 was fixed. But when I removed 'set', and imported collection becomes empty. I noticed it in a recent d16.0stg build.
We have a test for what you describe:
https://github.com/Microsoft/vs-mef/blob/4bcbb4f5d7f02f91f4b1623911fc1bd727bcaa72/src/tests/Microsoft.VisualStudio.Composition.Tests/RejectionTests.cs#L101-L106
What is different about your case that leads it to fail?
interesting, I hit this problem on a head of a MEF scope (UnconfiguredProjectImpl), so it is coming from ExportFactory<T>.CreateExport(). I wonder whether that makes any difference.
Would you be willing to try adding a test for it to see if you can repro it?