Can a C# Property ever have no GetMethod and no SetMethod

Browsing the source code on dotnet/corefx on GitHub for System.Linq.Expressions, I found the following code:

MethodInfo mi = property.GetGetMethod(true);
if (mi == null)
{
    mi = property.GetSetMethod(true);
    if (mi == null)
    {
        throw Error.PropertyDoesNotHaveAccessor(property, nameof(property));
    }
}

Is there any way that GetGetMethod and GetSetMethod can both return null, as seems to be accounted for here? Is this dead code? The C# compiler doesn't allow for a property to have no getter and no setter, so how is this possible for PropertyInfo