Xamarin Linker : Default constructor not found for type Cirrious.CrossCore.IoC.MvxPropertyInjector - xamarin.ios

Question

With a skeleton project with FirstView from HotTuna package, and with Build linker behavior set to "Link all assemblies", I get the following error:
System.MissingMethodException: Default constructor not found for type Cirrious.CrossCore.IoC.MvxPropertyInjector
Using NuGet package v3.1.1 for all MvvmCross (4 packages)
LinkerPleaseInclude file does have the line
[MonoTouch.Foundation.Preserve(AllMembers = true)]
Using the latest stable build:
On PC:
Xamarin for VS 1.12.278
Xamarin.iOS 1.12.278
Mac:
Xamarin.iOS 7.2.2.2
Of course with Linker behavior of SDK only, it runs fine. Any suggestions anyone?

Answer 1

Solved; So, with the basic project, there were three consecutive errors in the following order:
System.MissingMethodException: Default constructor not found for type Cirrious.CrossCore.IoC.MvxPropertyInjector
can be resolved either by --linkskip=Cirrious.Core (ugly), or by including the following in LinkerPleaseInclude.cs
public void Include(MvxPropertyInjector injector){
injector = new MvxPropertyInjector ();
}
Next error is:
Cirrious.CrossCore.Exceptions.MvxException: Failed to construct and initialize ViewModel for type {0} from locator MvxDefaultViewModelLocator - check MvxTrace for more information
This one is difficult; Simple fix is to ofcourse to do a --linkskip=portableLibrary, or to crate an instance of the ViewModel somewhere (perhaps in LinkerPleaseInclude.cs); problem with the second approach at-least in my case is, most of my VM doesn't have a parameter less constructor, and obviously using IOC in this case wouldn't help.
Final Error:
System.ArgumentNullException: missing source event info in MvxWeakEventSubscription
Parameter name: sourceEventInfo
Either use --linkskip=System (ugly), or add the following to LinkerPleaseInclude.cs
public void Include(INotifyPropertyChanged changed)
{
changed.PropertyChanged += (sender, e) => {
var test = e.PropertyName;
};
}
This was enough for my basic project to run with LinkAllAssemblies, Using LLVM optimizer, and Use SGen collector.
Hope this will help anyone looking for a solution.

Answer 2

I hit this when my XCode was out of sync with the latest Xamarin on my Mac. Upgrading XCode to the latest resolved the problem.