Bug 36942 - .NET 4.6 running on mono, Method 'Array.Empty' not found. (Win and Linux)
Summary: .NET 4.6 running on mono, Method 'Array.Empty' not found. (Win and Linux)
Alias: None
Product: Runtime
Classification: Mono
Component: JIT ()
Version: 4.2.0 (C6)
Hardware: All All
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2015-12-12 22:45 UTC by Dave
Modified: 2016-06-08 21:49 UTC (History)
6 users (show)

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

unit test / console line app which exhibits the issue (3.76 KB, text/plain)
2015-12-12 22:45 UTC, Dave

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Description Dave 2015-12-12 22:45:18 UTC
Created attachment 14262 [details]
unit test / console line app which exhibits the issue

[ERROR] FATAL UNHANDLED EXCEPTION: System.MissingMethodException: Method 'Array.Empty' not found.

This error seems to be appearing in a few Frameworks


The Nancy Guys think the following:

"This is what I think you're doing.

1.You are compiling your application on .NET Framework 4.6 where the absence of values to a params string[] parameter gets compiled into Array.Empty<T>() by Roslyn.
2.You then attempt to run this compiled application on an early build of .NET Framework or Mono, where Array.Empty<T> does not exist (source notice that it says Available since 4.6)"

Attached is an example bit of code which exhibits the issue.

it fails on the line

var subscribeAction = Expression.Lambda<Action>(callSubscribe); //Fails on mono
Comment 1 Marek Safar 2015-12-14 15:06:12 UTC
You need to upgrade to Mono 4.2 or newer which support .net 4.6
Comment 2 Craig Minihan 2016-06-07 09:57:00 UTC
I see this problem with Stable

It is easy to replicate:
* var array = new Array.Empty<string>();
* Build under VS2015 as a 4.6 app
* Run under Mono

You get:
craig@ubuntu:~/temp$ mono TestArrayEmpty.exe 

Unhandled Exception:
System.MissingMethodException: Method 'Array.Empty' not found.
[ERROR] FATAL UNHANDLED EXCEPTION: System.MissingMethodException: Method 'Array.Empty' not found.

I originally saw this problem with RabbitMQ 3.6.2 from nuget with an app built by VS2015 and run up under Mono 4.2 as above. RabbitMQ does *not* use Array.Empty directly.
Comment 3 Federico Dipuma 2016-06-08 21:49:17 UTC
Same issue using Mono stable under ARM Linux (Raspbian).

Encountered while testing a Nancy application as per this issue:


The application was built using .net 4.6.2, when reverted to 4.5.2 the issue disappeared.