F# on macOS - Fake fails to build - f#

Question

I am getting an error when trying to build a simple F# project on macOS High Sierra.
$ mono --version
Mono JIT compiler version 5.0.1.1 (2017-02/5077205 Sun Sep 17 18:29:46 BST 2017)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: normal
SIGSEGV: altstack
Notification: kqueue
Architecture: amd64
Disabled: none
Misc: softdebug
LLVM: supported, not enabled.
GC: sgen (concurrent by default)
Steps:
Open VS Code
Ionide New F# Project
Choose the Suave Project Template
$ mono .paket/paket.exe install
$ ./build.sh
The error is:
1) System.Exception: dotnet build failed
at FSI_0005.Build+runDotnet#40.Invoke (System.String message) [0x00001] in <c9993ec69ddb4848af99438005012ea7>:0
at Microsoft.FSharp.Core.PrintfImpl+StringPrintfEnv`1[TResult].Finalize () [0x00012] in <5893d081904cf4daa745038381d09358>:0
at Microsoft.FSharp.Core.PrintfImpl+Final1#224[TState,TResidue,TResult,A].Invoke (Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] env, A a) [0x00038] in <5893d081904cf4daa745038381d09358>:0
at Microsoft.FSharp.Core.OptimizedClosures+Invoke#3253[T2,TResult,T1].Invoke (T2 u) [0x00001] in <5893d081904cf4daa745038381d09358>:0
at FSI_0005.Build.runDotnet (System.String workingDir, System.String args) [0x00048] in <c9993ec69ddb4848af99438005012ea7>:0
at FSI_0005.Build+clo#64-6.Invoke (System.String p) [0x0000a] in <c9993ec69ddb4848af99438005012ea7>:0
at Microsoft.FSharp.Collections.SeqModule.Iterate[T] (Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] action, System.Collections.Generic.IEnumerable`1[T] source) [0x0002d] in <5893d081904cf4daa745038381d09358>:0
at FSI_0005.Build+clo#62-5.Invoke (Microsoft.FSharp.Core.Unit _arg4) [0x0000b] in <c9993ec69ddb4848af99438005012ea7>:0
at Fake.TargetHelper+targetFromTemplate#209-1[a].Invoke (Microsoft.FSharp.Core.Unit unitVar0) [0x00001] in <59b649fdccf1c534a7450383fd49b659>:0
at Fake.TargetHelper.runSingleTarget (Fake.TargetHelper+TargetTemplate`1[a] target) [0x0004b] in <59b649fdccf1c534a7450383fd49b659>:0
How can I get this working?

Answer 1

Ionide did not pick the correct target framework by default.
You need to make the following changes:
To *.fsproj, change the target framework to:
<TargetFramework>netcoreapp2.0</TargetFramework>
To paket.dependencies, change the framework to:
framework: >= netcoreapp2.0
Run Paket again:
$ mono .paket/paket.exe install
Run the build script again:
$ ./build.sh