Bug 57530 - "MT2001: Could not link assemblies. Reason: value cannot be null." on autoproperty with Mono 5.0.1
Summary: "MT2001: Could not link assemblies. Reason: value cannot be null." on autopro...
Status: RESOLVED DUPLICATE of bug 56974
Alias: None
Product: Forms
Classification: Xamarin
Component: iOS ()
Version: 2.3.4
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2017-06-15 17:47 UTC by Chris Charabaruk
Modified: 2017-06-26 13:56 UTC (History)
6 users (show)

Is this bug a regression?: ---
Last known good build:

Local developer's build log (3.37 MB, text/plain)
2017-06-15 17:47 UTC, Chris Charabaruk
Mobile Center build log (465.31 KB, text/plain)
2017-06-15 17:47 UTC, Chris Charabaruk

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Description Chris Charabaruk 2017-06-15 17:47:30 UTC
Created attachment 22929 [details]
Local developer's build log

Encountering this both with Visual Studio for Mac and Azure Mobile Center Build for iOS when using Mono 5.0.1, but NOT when using Mono 4.8.1. Our system running VS/Mac uses Xamarin.iOS but I'm not sure what particular version is used on Mobile Center.
Comment 1 Chris Charabaruk 2017-06-15 17:47:57 UTC
Created attachment 22930 [details]
Mobile Center build log
Comment 2 Chris Charabaruk 2017-06-15 17:57:44 UTC
Our local dev's VS Mac version information:

=== Visual Studio Community 2017 for Mac ===

Version 7.0.1 (build 24)
Installation UUID: d7b994ce-3578-4d37-a740-207e0b7a3a16
    Mono (2017-02/5077205) (64-bit)
    GTK+ 2.24.23 (Raleigh theme)

    Package version: 500010001

=== NuGet ===


=== .NET Core ===

Runtime: /usr/local/share/dotnet/dotnet
SDK: /usr/local/share/dotnet/sdk/1.0.3/Sdks
MSBuild SDKs: /Library/Frameworks/Mono.framework/Versions/5.0.1/lib/mono/msbuild/15.0/bin/Sdks

=== Xamarin.Profiler ===

Version: 1.5.4
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

=== Xamarin.Android ===

Version: (Visual Studio Community)
Android SDK: /Users/elsieyang/Library/Developer/Xamarin/android-sdk-macosx
    Supported Android versions:
        6.0 (API level 23)

SDK Tools Version: 25.2.5
SDK Platform Tools Version: 25.0.5
SDK Build Tools Version: 25.0.3

Java SDK: /usr
java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)

Android Designer EPL code available here:

=== Apple Developer Tools ===

Xcode 8.3.2 (12175)
Build 8E2002

=== Xamarin.iOS ===

Version: (Visual Studio Community)
Hash: d2270eec
Branch: d15-2
Build date: 2017-05-22 16:30:53-0400

=== Xamarin.Mac ===

Version: (Visual Studio Community)

=== Xamarin Inspector ===

Version: 1.2.2
Hash: b71b035
Branch: d15-1
Build date: Fri, 21 Apr 2017 17:57:12 GMT

=== Build Information ===

Release ID: 700010024
Git revision: 7ab1ca2ced6f584e56b7a0d4d321d00775cd95c9
Build date: 2017-05-19 05:44:51-04
Xamarin addins: 08d17158f3365beee5e60f67999e607cce4b3f93
Build lane: monodevelop-lion-d15-2

=== Operating System ===

Mac OS X 10.12.4
Darwin 16.5.0 Darwin Kernel Version 16.5.0
    Fri Mar  3 16:52:33 PST 2017
    root:xnu-3789.51.2~3/RELEASE_X86_64 x86_64
Comment 3 Vincent Dondain [MSFT] 2017-06-15 22:07:20 UTC

Any chance you can provide a quick test case that isolates the issue or a way to reproduce it?

I could also make this entire bug private so it can only be accessed by Xamarin employees if you want to share more private code.
Comment 4 Chris Charabaruk 2017-06-22 14:56:09 UTC
Sorry for taking a week to get back to this (temporarily had to do another project) but I can't isolate anything in particular that would cause this. set_Posted is just your average, run of the mill auto-property setter, though.
Comment 5 Chris 2017-06-22 17:06:51 UTC
I am also having this issue.  Will try to collect some details when I have a chance.
Comment 6 Rolf Bjarne Kvinge [MSFT] 2017-06-23 07:46:13 UTC
This looks like it's a bug in Xamarin.Forms: bug #56974, which is fixed in a prerelease version of Xamarin.Forms.

Can you try updating and see if that fixes the problem?
Comment 7 Chris Charabaruk 2017-06-23 15:33:54 UTC
I'll give it a try but that's not a solution we can run with. Is there an ETA on 2.3.5?
Comment 8 Chris Charabaruk 2017-06-23 17:18:41 UTC
Yeah, looks like has the fix in. Too bad we can't use that for our app production/distribution builds, we need an official 2.3.5 release.
Comment 9 Rolf Bjarne Kvinge [MSFT] 2017-06-26 12:35:05 UTC
OK, marking as duplicate of bug #56974 then.

I'm reassigning to the Forms team so that they can give an answer about an ETA for 2.3.5.

*** This bug has been marked as a duplicate of bug 56974 ***
Comment 10 David Ortinau [MSFT] 2017-06-26 13:56:07 UTC
Chris, is undergoing our QA now. So long as we don't hit any major regressions there or from community pre-prerelease testers, expect we will make it stable this week.