Imported Upstream version 5.18.0.142

Former-commit-id: 7467d4b717762eeaf652d77f1486dd11ffb1ff1f

mcs/errors/cs1644-64.cs

@@ -0,0 +1,13 @@
+// CS1644: Feature `expression body property accessor' cannot be used because it is not part of the C# 6.0 language specification 
+// Line: 11
+// Compiler options: -langversion:6
+
+using System;
+
+class C
+{
+	public int Integer
+	{
+		get => 0;
+	}
+}