Bug 12838 - System.Core.dll should not be referenced automatically when targeting Mono / .NET 2.0
Summary: System.Core.dll should not be referenced automatically when targeting Mono / ...
Alias: None
Product: Xamarin Studio
Classification: Desktop
Component: Project Model ()
Version: 4.0.5
Hardware: PC Linux
: --- normal
Target Milestone: master
Assignee: Lluis Sanchez
Depends on:
Reported: 2013-06-23 13:48 UTC by Michael Möller
Modified: 2013-06-25 11:32 UTC (History)
2 users (show)

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

Small project demonstrating the problem. (1.38 KB, application/x-gzip)
2013-06-23 13:48 UTC, Michael Möller

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Description Michael Möller 2013-06-23 13:48:37 UTC
Created attachment 4181 [details]
Small project demonstrating the problem.

MonoDevelop automatically adds System.Core.dll as a reference when calling the compiler, even for projects with "Target framework" configured to "Mono / .NET 2.0". This reference is not listed in the project inside MonoDevelop, so it can't be removed manually. The command line looks something like this:

/usr/bin/mcs /noconfig "/r:/usr/lib/mono/2.0/mscorlib.dll" -nostdlib "/out:/home/michael/Test/Project/bin/Debug/Project.exe" "/r:/usr/lib/mono/2.0/System.dll" "/r:/usr/lib/mono/2.0/System.Core.dll" /nologo /warn:4 /debug:full /optimize- /codepage:utf8 /platform:x86 "/define:DEBUG"  /t:exe "/home/michael/Test/Project/Program.cs" 

In certain cases (for example when using a System.Linq reimplementation for .NET 2.0) this can lead to errors as for example this one:

"Error CS0121: The call is ambiguous between the following methods or properties: `System.Linq.Enumerable.Count<int>(this System.Collections.Generic.IEnumerable<int>)' and `System.Linq.Enumerable.Count<int>(this System.Collections.Generic.IEnumerable<int>)' (CS0121) (Project)"

Removing "/r:/usr/lib/mono/2.0/System.Core.dll" from the command and invoking the compiler directly from the command line allows the program to compile (and run) just fine.

As far as I know the System.Core.dll did not exist prior to .NET 3.5, so I am not sure why it can be referenced. And in any case the reference should not be forced by MonoDevelop.
Comment 1 Lluis Sanchez 2013-06-25 11:32:58 UTC
Fixed in master.