F# 4.1 compiler raises warnings

I created a new console project in VS 2017 RC, add FSharpPlus NuGet dependency into it, copied the follwing code into it:

open FSharpPlus

[<EntryPoint>]
let main argv = 
    let lst11n21n12n22 = 
        monad {                
            let! x1 = [1;   2]
            let! x2 = [10; 20]
            return ((+) x1 x2)}
    
    let neLst11n21n12n22 = 
        monad {                
            let! x1 = { NonEmptyList.Head =  1; Tail =  [2] }
            let! x2 = { NonEmptyList.Head = 10; Tail = [20] }
            return ((+) x1 x2)}
    
    let some14 = 
        monad {                
            let! x1 = Some 4
            let! x2 = Some 10
            return ((+) x1 x2)}
    0

and try to compile. It’s compiled successfully, but with some strangely looking warnings:

1>------ Rebuild All started: Project: FSharpPlusTest, Configuration: Debug Any CPU ------ 1> C:\Program Files (x86)\Microsoft SDKs\F#\4.1\Framework\v4.0\fsc.exe -o:obj\Debug\FSharpPlusTest.exe 1>-g 1>–debug:full 1>–noframework 1>–define:DEBUG 1>–define:TRACE 1>–doc:bin\Debug\FSharpPlusTest.XML 1>–optimize- 1>–tailcalls- 1>–platform:anycpu32bitpreferred 1>-r:D:\github\FSharpPlusTest\packages\FsControl.1.0.9\lib\net40\FsControl.Core.dll 1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\FSharp.NETFramework\v4.0\4.4.0.0\FSharp.Core.dll 1>-r:D:\github\FSharpPlusTest\packages\FSharpPlus.0.0.4\lib\net40\FSharpPlus.dll 1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\mscorlib.dll 1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\System.Core.dll 1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\System.dll 1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.6.1\System.Numerics.dll 1>–target:exe 1>–warn:3 1>–warnaserror:76 1>–vserrors 1>–utf8output 1>–fullpaths 1>–flaterrors 1>–subsystemversion:6.00 1>–highentropyva+ 1>C:\temp.NETFramework,Version=v4.6.1.AssemblyAttributes.fs 1>AssemblyInfo.fs 1>Program.fs 1> 1>FSC: warning 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 879 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 880 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 881 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 1118 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 1141 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 1164 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. 1>FSC: warning FS3186: An error occurred while reading the F# metadata node at position 1256 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. 1> FSharpPlusTest -> D:\github\FSharpPlusTest\FSharpPlusTest\bin\Debug\FSharpPlusTest.exe ========== Rebuild All: 1 succeeded, 0 failed, 0 skipped ==========

[gusty]

We can reopen it if someone keep receiving these warnings.

[wallymathieu]

I didn’t remove the #nowarns, just moved them