C# generics type interference strange behaviour -

consider following code :

class program {     static void main(string[] args)     {         var = new a();         var b = new b();         print(a);         print(b);         console.writeline(b.hello);         console.readline();     }      static void print<t>(t t) t :     {         console.writeline(typeof(t));         console.writeline(t.gettype());         console.writeline(t.hello);     } }  public class {     public string hello { { return "helloa"; } } }  public class b : {     public new string hello { { return "hellob"; } } } 

the output got (.net fw 4.5)

• //print(a)
• a
• a
• helloa
• //print(b)
• b
• b
• helloa
• //explicit writeline
• hellob

can explain how got 2nd helloa, expecting hellob ?

public new string hello { { return "hellob"; } } 

the new keyword creates new function happens have same name old one. thus, b has 2 methods: hello (a), executed when invoked through variable of compile-time type a, , hello (b), executed when invoked through variable of compile-time type b (or subtype thereof).

since generic parameter t : a, compiler compiles t.hello call hello (a).

b shadows (or hides) method hello rather overriding it.

what wanted write was:

public class {     public virtual string hello { { return "helloa"; } } }  public class b : {     public override string hello { { return "hellob"; } } } 

note base method declared virtual, , subclass method override.