Can not build with F#4.0/VS2015 - FS3186 error reading F# metadata node

[dtchepak]

I have a feeling that this is going to be difficult to sort out, as I can't reproduce it in a new project. I thought I'd report it in case you had any tips for me to work around it.

I have a project that depends on Fleece. The build fails on VS2015/F#4.0 with the following error:

FS3186: An error occurred while reading the F# metadata node at position 878 in table 'ivals' of assembly 'FsControl.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly you are using.

Dependencies:

  <package id="Fleece" version="0.4.0" targetFramework="net4" />
  <package id="FsControl" version="1.0.9" targetFramework="net4" />
  <package id="FSharpPlus" version="0.0.4" targetFramework="net4" />

Builds fine with Microsoft Build Tools 2013 / VS2013.

Edit 2016-04-05:
Workaround: add nowarn.

[mausch]

Have you tried building FsControl itself with F# 4.0 ?

[dtchepak]

Same error building FsControl. Sorry, should have done that first. :-\

Trying to build with F# 4.0:

3>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 1482 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly you are using.

[mausch]

So you're using the F# 4.0 compiler but apparently FSharp.Core.dll is still the one for F# 3.1 ? Could you confirm that, and if that's the case compile against https://www.nuget.org/packages/FSharp.Core/4.0.0.1 instead?

[delexi]

I get the same or similar warning, when trying to compile FSharpPlus on Linux.

I just cloned the repo and executed the following command line:

$ fsharpi --exec build.fsx 
Building project with version: LocalBuild
Shortened DependencyGraph for Target BuildSolution:
<== BuildSolution
   <== Clean
   <== RestorePackages

The resulting target order is:
 - Clean
 - RestorePackages
 - BuildSolution
Starting Target: Clean 
Deleting contents of ./build
Finished Target: Clean
Starting Target: RestorePackages 
mono  /home/delexi/code/ext/FSharpPlus/packages/NuGet/NuGet.exe  "install" "/home/delexi/code/ext/FSharpPlus/FSharpPlu
s/packages.config" "-OutputDirectory" "/home/delexi/code/ext/FSharpPlus/packages"                                    
Finished Target: RestorePackages
Starting Target: BuildSolution (==> Clean, RestorePackages)
Building project: ./FSharpPlus.sln
  xbuild  ./FSharpPlus.sln /t:Build    /p:RestorePackages="False" /p:Configuration="Release" /logger:Fake.MsBuildLogge
r+ErrorLogger,"/home/delexi/code/ext/FSharpPlus/packages/FAKE/tools/FakeLib.dll"                                     
xbuild  ./FSharpPlus.sln /t:Build    /p:RestorePackages="False" /p:Configuration="Release" /logger:Fake.MsBuildLogger+
ErrorLogger,"/home/delexi/code/ext/FSharpPlus/packages/FAKE/tools/FakeLib.dll"                                       
XBuild Engine Version 12.0
Mono, Version 4.0.2.0
Copyright (C) 2005-2013 Various Mono authors

Build started 8/25/2015 9:36:52 PM.
__________________________________________________
Project "/home/delexi/code/ext/FSharpPlus/FSharpPlus.sln" (Build target(s)):
        Target ValidateSolutionConfiguration:
                Building solution configuration "Release|Any CPU".
        Target Build:
                Project "/home/delexi/code/ext/FSharpPlus/FSharpPlus/FSharpPlus.fsproj" (default target(s)):
                        Target PrepareForBuild:
                                Configuration: Release Platform: AnyCPU
                        Target CopyFilesMarkedCopyLocal:
                                Copying file from '/home/delexi/code/ext/FSharpPlus/packages/FsControl.2.0.0-CI00005/l
ib/net40/FsControl.Core.dll' to '/home/delexi/code/ext/FSharpPlus/build/FsControl.Core.dll'                          
                        Target GenerateSatelliteAssemblies:
                        No input files were specified for target GenerateSatelliteAssemblies, skipping.
                        Target CoreCompile:
                                Tool /usr/lib/mono/4.5/fsc.exe execution started with arguments: -o:obj/Release/FSharp
Plus.dll --debug:pdbonly --noframework --define:TRACE --doc:bin/Release/FSharpPlus.XML --optimize+ -r:../packages/FsCo
ntrol.2.0.0-CI00005/lib/net40/FsControl.Core.dll -r:/usr/lib/mono/4.0/mscorlib.dll -r:/usr/lib/mono/4.0/System.dll -r:
/usr/lib/mono/4.0/System.Numerics.dll -r:/usr/lib/mono/gac/FSharp.Core/4.3.0.0__b03f5f7f11d50a3a/FSharp.Core.dll -r:/u
sr/lib/mono/4.0/System.Core.dll --target:library --warn:3 --warnaserror:76 --fullpaths --flaterrors --highentropyva- A
ssemblyInfo.fs Operators.fs Builders.fs Extensions.fs NonEmptyList.fs ZipList.fs ParallelArray.fs                    
                                F# Compiler for F# 4.0 (Open Source Edition)
                                Freely distributed under the Apache 2.0 Open Source License
/home/delexi/code/ext/FSharpPlus/FSharpPlus/unknown(1,1): warning FS3186: An error occurred while reading the F# metad
ata node at position 1481 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyTok
en=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly 
you are using.                                                                                                       
/home/delexi/code/ext/FSharpPlus/FSharpPlus/unknown(1,1): warning FS3186: An error occurred while reading the F# metad
ata node at position 1482 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyTok
en=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly 
you are using.                                                                                                       
/home/delexi/code/ext/FSharpPlus/FSharpPlus/unknown(1,1): warning FS3186: An error occurred while reading the F# metad
ata node at position 1483 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyTok
en=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly 
you are using.                                                                                                       
/home/delexi/code/ext/FSharpPlus/FSharpPlus/unknown(1,1): warning FS3186: An error occurred while reading the F# metad
ata node at position 1497 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyTok
en=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly 
you are using.                                                                                                       
/home/delexi/code/ext/FSharpPlus/FSharpPlus/unknown(1,1): warning FS3186: An error occurred while reading the F# metad
ata node at position 1498 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyTok
en=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly 
you are using.                                                                                                       
/home/delexi/code/ext/FSharpPlus/FSharpPlus/unknown(1,1): warning FS3186: An error occurred while reading the F# metad
ata node at position 1499 in table 'ivals' of assembly 'FsControl.Core, Version=2.0.0.0, Culture=neutral, PublicKeyTok
en=null'. The node had no matching declaration. Please report this warning. You may need to recompile the F# assembly 
you are using.

To me it seems like I am compiling against FSharp.Core 4.3.0.

[gusty]

I don't know if those warnings will result in any compile or runtime error. I tried to rebuild the project in myget, it seems now they updated their compiler to the one from VS2015 because now I get those warnings there too.
Anyway the project still compiles and the tests succeed but would be nice to do a small reproduction of the issue and submit it to the F# Team.

[delexi]

I get those warnings and after that the compilation process seems to hang in some infinite loop with 100% CPU usage. If you have an idea how to investigate that further, do tell me.

[gusty]

Be aware that the project takes some time to compile, the last build I did took about 14 mins in myget.

[delexi]

That was indeed the case, I just did not wait long enough. Thanks!

[gusty]

Submitted an issue to the F# compiler.