Compiler Error CS0405

Duplicate constraint 'constraint' for type parameter 'type parameter'

Two of the constraints on the generic declaration are identical. To get rid of the error, remove the duplicate.

The following sample generates CS0405:

// CS0405.cs  
interface I  
{  
}  
  
class C<T> where T : I, I  // CS0405.cs  
{  
}