class Base1 {  };
class Base2 {  }

interface I1   {   }
interface I2   {   }

class C : I1,I2 { }

static class Program
{

    static T M1<T>(this T t,I1 x) where T : Base1
    {
        return t;
    }

    static T M1<T>(this T t,I2 x) where T : Base2
    {
        return t;
    }

    static void Main(string[] args)
    {
        Base1 b1 = new Base1();
        C c = new C();
        b1.M1(c);
    }
}

错误是

The call is ambiguous between the following methods or properties: ‘ConsoleApplication1.Program.M1<ConsoleApplication1.Base1>(ConsoleApplication1.Base1,ConsoleApplication1.I1)‘ and ‘ConsoleApplication1.Program.M1<ConsoleApplication1.Base1>(ConsoleApplication1.Base1,ConsoleApplication1.I2)‘

我认为编译器可以使用“where”子句区分两种方法