#nowarn "2003" doesn't disable FS2003? - f#

Question

The following code, compiled in a fresh console project in VS2017 (v15.2), fails to suppress the FS2003 warning (which the #nowarn directive should suppress). I'm targeting F# 4.1 (FSharp.Core 4.4.1.0). Am I missing something here?
This attribute is to be used in existing generated code, so I want to use #nowarn rather than change every F# project's settings to ignore this warning. We compile with warnings treated as errors.
open System.Reflection
#nowarn "2003"
[<assembly: AssemblyInformationalVersion("13.3.1.74-g5224f3b")>]
do() // necessary for the assembly attribute
[<EntryPoint>]
let main argv = 0
Compiler output in VS is
1>------ Rebuild All started: Project: ConsoleApplication4, Configuration: Release Any CPU ------
1> C:\Program Files (x86)\Microsoft SDKs\F#\4.1\Framework\v4.0\fsc.exe -o:obj\Release\ConsoleApplication4.exe
1>--debug:pdbonly
1>--noframework
1>--define:TRACE
1>--doc:bin\Release\ConsoleApplication4.XML
1>--optimize+
1>--platform:anycpu32bitpreferred
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\FSharp\.NETFramework\v4.0\4.4.1.0\FSharp.Core.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\mscorlib.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\System.Core.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\System.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\System.Numerics.dll
1>-r:C:\Users\cnichols\Documents\Visual Studio 2017\Projects\ConsoleApplication4\packages\System.ValueTuple.4.3.0\lib\netstandard1.0\System.ValueTuple.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Collections.Concurrent.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Collections.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ComponentModel.Annotations.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ComponentModel.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ComponentModel.EventBasedAsync.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Diagnostics.Contracts.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Diagnostics.Debug.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Diagnostics.Tools.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Diagnostics.Tracing.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Dynamic.Runtime.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Globalization.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.IO.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Linq.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Linq.Expressions.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Linq.Parallel.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Linq.Queryable.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Net.NetworkInformation.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Net.Primitives.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Net.Requests.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Net.WebHeaderCollection.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ObjectModel.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Reflection.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Reflection.Emit.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Reflection.Emit.ILGeneration.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Reflection.Emit.Lightweight.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Reflection.Extensions.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Reflection.Primitives.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Resources.ResourceManager.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.Extensions.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.Handles.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.InteropServices.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.InteropServices.WindowsRuntime.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.Numerics.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.Serialization.Json.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.Serialization.Primitives.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Runtime.Serialization.Xml.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Security.Principal.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ServiceModel.Duplex.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ServiceModel.Http.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ServiceModel.NetTcp.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ServiceModel.Primitives.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.ServiceModel.Security.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Text.Encoding.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Text.Encoding.Extensions.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Text.RegularExpressions.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Threading.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Threading.Tasks.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Threading.Tasks.Parallel.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Threading.Timer.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Xml.ReaderWriter.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Xml.XDocument.dll
1>-r:C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\Facades\System.Xml.XmlSerializer.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:\Users\cnichols\AppData\Local\Temp\.NETFramework,Version=v4.6.2.AssemblyAttributes.fs
1>AssemblyInfo.fs
1>Program.fs
1>
1>FSC: warning FS2003: An System.Reflection.AssemblyInformationalVersionAttribute specified version '13.3.1.74-g5224f3b', but this value is invalid and has been ignored
1> ConsoleApplication4 -> C:\Users\cnichols\Documents\Visual Studio 2017\Projects\ConsoleApplication4\ConsoleApplication4\bin\Release\ConsoleApplication4.exe
========== Rebuild All: 1 succeeded, 0 failed, 0 skipped ==========
Updates
Problem reproduced after a reboot.
Problem reproduced on VS 2017 15.2 26430.4.
Problem reproduced on VS 2017 15.2 26430.6.
Problem reproduced on VS 2015 14.0.25431.01 Update 3.
Problem reproduced on a different PC.
Opened an issue against F#: #nowarn “2003” doesn't disable FS2003 #3139

Answer 1

This is not the same kind of warning as normal warnings.
Try changing your main to let main argv = 5; 0 - you'll get a warning about ignoring the value 5. Check out how its formatting is different: it has file name, line, column, etc.
Also, notice how FS2003 doesn't show up if there are build errors. This points to it being emitted not by the compiler proper, but after the fact, while assembling the assembly and plugging the version in the metadata.
More importantly, this warning FS2003 will not get converted to an error when building with "warnings as errors". So the bottom line is, just ignore it.

Answer 2

Microsoft has assigned a priority to this bug and has a proper, working repro.
And again, this warning clearly does get converted to an error when building with "warnings as errors."