Imported Upstream version 5.10.0.47

Former-commit-id: d0813289fa2d35e1f8ed77530acb4fb1df441bc0

mcs/errors/cs4012-3.cs

@@ -0,0 +1,19 @@
+// CS4012: Parameters or local variables of type `S' cannot be declared in async methods or iterators
+// Line: 16
+// Compiler options: -langversion:latest
+
+using System;
+using System.Threading.Tasks;
+
+public ref struct S
+{
+}
+
+class C
+{
+	public async void Test ()
+	{
+		var tr = new S ();
+		await Task.Factory.StartNew (() => 6);
+	}
+}