Hello World doesn't work with reflection disabled in NAOT

[WhiteBlackGoose]

$ ./output/fs-hello-world
Unhandled Exception: EETypeRva:0x0037B3E0: TypeInitialization_Type_NoTypeAvailable
 ---> EETypeRva:0x0037B3E0: TypeInitialization_Type_NoTypeAvailable
 ---> EETypeRva:0x0037AA80: Reflection_Disabled

Repro steps

dotnet new console -n fs-hello-world -lang F# && cd fs-hello-world
dotnet publish \
-p:SelfContained=true \
-p:PublishAot=true \
-p:IlcDisableReflection=true \
-o ./output
./output/fs-hello-world

Program.fs:

printfn "Hello from F#"

Expected behavior

Prints hello world

Actual behavior

Unhandled Exception: EETypeRva:0x0037B3E0: TypeInitialization_Type_NoTypeAvailable
 ---> EETypeRva:0x0037B3E0: TypeInitialization_Type_NoTypeAvailable
 ---> EETypeRva:0x0037AA80: Reflection_Disabled
   at Internal.Reflection.RuntimeTypeInfo.GetMethodImpl(String, BindingFlags, Binder, CallingConventions, Type[], ParameterModifier[]) + 0x5a
   at System.Type.GetMethod(String, BindingFlags) + 0x5a
   at <StartupCode$FSharp-Core>.$Printf..cctor() + 0x4d
   at System.Runtime.CompilerServices.ClassConstructorRunner.EnsureClassConstructorRun(StaticClassConstructionContext*) + 0x158
   Exception_EndOfInnerExceptionStack
   at System.Runtime.CompilerServices.ClassConstructorRunner.EnsureClassConstructorRun(StaticClassConstructionContext*) + 0x253
   at System.Runtime.CompilerServices.ClassConstructorRunner.CheckStaticClassConstructionReturnNonGCStaticBase(StaticClassConstructionContext*, IntPtr) + 0x1b
   at Microsoft.FSharp.Core.PrintfImpl..cctor() + 0x9
   at System.Runtime.CompilerServices.ClassConstructorRunner.EnsureClassConstructorRun(StaticClassConstructionContext*) + 0x158
   Exception_EndOfInnerExceptionStack
   at System.Runtime.CompilerServices.ClassConstructorRunner.EnsureClassConstructorRun(StaticClassConstructionContext*) + 0x253
   at System.Runtime.CompilerServices.ClassConstructorRunner.CheckStaticClassConstructionReturnNonGCStaticBase(StaticClassConstructionContext*, IntPtr) + 0x1b
   at Microsoft.FSharp.Core.PrintfImpl.revToArray[T](Int32, FSharpList`1) + 0x36
   at Microsoft.FSharp.Core.PrintfImpl.FormatParser`4.parseAndCreateFuncFactoryAux(FSharpList`1, String, Type, Int32&) + 0xbb
   at Microsoft.FSharp.Core.PrintfImpl.FormatParser`4.parseAndCreateFunctionFactory() + 0xee
   at Microsoft.FSharp.Core.PrintfImpl.FormatParser`4.GetCurriedPrinterFactory() + 0x38
   at Microsoft.FSharp.Core.PrintfModule.gprintf[a, TState, TResidue, TResult, TPrinter](FSharpFunc`2, PrintfFormat`4) + 0xac
   at <StartupCode$sandbox-1668861381>.$Program.main@() + 0x44
   at sandbox-1668861381!<BaseAddress>+0x228cc9
   at sandbox-1668861381!<BaseAddress>+0x228d3c
Aborted

• debian 12
• gcc (Debian 12.2.0-9) 12.2.0
• Debian clang version 14.0.6
• SDK 7.0.100

[En3Tho]

It's a problem of printf family specifically. Console.WriteLine should work. I belive there was a flag of some sort planned to F# 7 to generate reflection free code but I'm not sure I'm correct here.

[vzarytovskii]

A good thing to track in our aot bucket

[ratsclub]

This is currently working on my machine:

$ dotnet publish -p:SelfContained=true -p:PublishAot=true -p:IlcDisableReflection=true -o ./output
MSBuild version 17.3.2+561848881 for .NET
  Determining projects to restore...
  All projects are up-to-date for restore.
  fs-hello-world -> /tmp/fs-hello-world/bin/Debug/net6.0/linux-x64/fs-hello-world.dll
  fs-hello-world -> /tmp/fs-hello-world/output/

$ ./output/fs-hello-world
Hello from F#

$ dotnet --version
6.0.408

[MichalStrehovsky]

This is currently working on my machine:

PublishAot doesn't do anything on .NET 6 - it was introduced in .NET 7.

Note IlcDisableReflection is an unsupported switch: we have no intention to stop using reflection in the runtime repo. We fix the issues found by IlcDisableReflection if the reflection use is unnecessary/avoidable, but don't go to great lengths - we're fine Won't fixing these since the mode is unsupported and we have no plans to make it supported.

[charlesroddie]

This would be fixed by:

• Implementing print and printn alongside printf and printfn fsharp/fslang-suggestions#1092
• Adjusting the template to use printn rather than printfn