Converting Array to IEnumerable

Question

To my surprise, I get the following statement:

public static IEnumerable AllEnums 
  => Enum.GetValues(typeof(SomeType));

to

Answer 1

I thought that the latter was inheriting from the former.

Enum.GetValues returns Array, which implements the non-generic IEnumerable, so you need to add a cast:

public static IEnumerable AllEnums = Enum.GetValues(typeof(SomeType))
    .Cast()
    .ToList(); 

This works with LINQ because Cast extension method is defined for the non-generic IEnumerable interface, not only on IEnumerable.

Edit: A call of ToList() avoid inefficiency associated with walking multiple times an IEnumerable produced by LINQ methods with deferred execution. Thanks, Marc, for a great comment!