Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0' or one of its dependencies.

[13thirteen]

Hi!
First, thank you so much for this meta package!
I recently ported my VS extension to it. Since I want my extension to be compatible with VS 2017 15.0 and later, it references Madskristensen.VisualStudio.SDK version 15.0.81-pre.

My extension also makes use of some Common Project System features, so it also references Microsoft.VisualStudio.ProjectSystem.SDK version 15.0.737.

Soon after releasing it, I received error reports that triggering the CPS feature in my extension will pop up the following error on certain Visual Studio 2017 versions:

Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

Testing showed that this error only appears in a certain range of Visual Studio 2017 versions:

• 15.4.0 - No problem
• 15.6.2 - Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0'
• 15.6.7 - Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0'
• 15.7.0 - Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0'
• 15.7.4 - Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0'
• 15.7.5 - Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0'
• 15.7.6 - Could not load file or assembly 'System.Collections.Immutable, Version=1.2.3.0'
• 15.8.9 - No problem
• 15.9.3 - No problem
• 15.9.6 - No problem

Now I saw that you included Microsoft.VisualStudio.ProjectSystem.SDK in #2 but removed it again in commit 552d567 "due to incompatibility".
Would you mind to elaborate on this incompatibility?

Furthermore, I saw that you added System.Collections.Immutable version 1.3.1 in commit f122001 and updated it to version 1.5.0 in commit a9b802a, also for the meta package targeting VS 15.0.
Comparing the System.Collections.Immutable.dll assemblies included in Visual Studio 15.7.6 and 15.8.9 (in the C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\PrivateAssemblies\ folder) shows: The dll included in VS 15.7.6 has the same file version as the dll in nuget package System.Collections.Immutable version 1.3.1 whereas the dll included in VS 15.8.9 has the same file version as the dll in nuget package System.Collections.Immutable version 1.5.0.
Could this be a reason that the error no longer occurs in VS 15.8.9 or later?

Any other ideas or suggestions?

[quasarea]

Using VS BuildTools 2017 15.9.11 I'm getting similar:

Could not resolve this reference. Could not locate the assembly "System.Collections.Immutable, Version=1.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.