Test NodeCode

tests/FSharp.Compiler.ComponentTests/CompilerService/AsyncMemoize.fs

@@ -211,6 +211,43 @@ let ``Job is restarted if first requestor cancels but keeps running if second re
 type ExpectedException() =
     inherit Exception()
 
+[<Fact>]
+let internal ``NodeCode preserves DiagnosticsThreadStatics`` () =
+    let random =
+        let rng = Random()
+        fun n -> rng.Next n
+
+    let job _ = node {
+        do! random 10 |> Async.Sleep |> NodeCode.AwaitAsync
+    }
+
+    let work (phase: BuildPhase) =
+        node {
+            use _ = new CompilationGlobalsScope(DiscardErrorsLogger, phase)
+            let! _ = Seq.init 8 job |> NodeCode.Parallel
+            Assert.Equal(phase, DiagnosticsThreadStatics.BuildPhase)
+        }
+
+    let phases = [|
+        BuildPhase.DefaultPhase
+        BuildPhase.Compile
+        BuildPhase.Parameter
+        BuildPhase.Parse
+        BuildPhase.TypeCheck
+        BuildPhase.CodeGen
+        BuildPhase.Optimize
+        BuildPhase.IlxGen
+        BuildPhase.IlGen
+        BuildPhase.Output
+        BuildPhase.Interactive
+    |]
+
+    let pickRandomPhase _ = phases[random phases.Length]
+    Seq.init 100 pickRandomPhase
+    |> Seq.map (work >> Async.AwaitNodeCode)
+    |> Async.Parallel
+    |> Async.RunSynchronously
+
 [<Fact>]
 let ``Stress test`` () =