Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/errors/cs4015.cs

@@ -0,0 +1,14 @@
+// CS4015: `C.SynchronousCall(int)': Async methods cannot use `MethodImplOptions.Synchronized'
+// Line: 9
+
+using System.Threading.Tasks;
+using System.Runtime.CompilerServices;
+
+class C
+{
+	[MethodImplAttribute(MethodImplOptions.Synchronized)]
+	public static async Task SynchronousCall (int arg)
+	{
+		await Task.FromResult (1);
+	}
+}