using System; public class A { public A (Action action) { } } public class B : A { public B () : base (() => { dynamic d = 1; Test (d); }) { } static decimal Test (dynamic arg) { return 3m; } } public class B2 { public Action a = () => { dynamic d = 1; Test (d); }; static decimal Test (dynamic arg) { return 3m; } } class M { static void Main () { new B (); new B2 (); } }