Re: [xml-dev] Does it make sense to have a default with a nillable eleme

https://www.w3.org/TR/xmlschema11-1/#c-evc

says something about default values and xsi:nill

> E has neither element nor character [children], and E is not ·nilled·...

in full it says

5 The appropriate case among the following is true:

5.1 If D has a {value constraint}, and E has neither element nor character [children], and E is not ·nilled· with respect to D , then all of the following are true:

5.1.1 If E's ·governing type definition· is an ·instance-specified type definition·, then D.{value constraint} is a valid default for the ·governing type definition· as defined in Element Default Valid (Immediate) (§3.3.6.2).

5.1.2 The element information item with D.{value constraint}.{lexical form} used as its ·normalized value· is locally ·valid· with respect to the ·governing type definition· as defined by Element Locally Valid (Type) (§3.3.4.4).

5.2 If D has no {value constraint}, or E has either element or character [children], or E is ·nilled· with respect to D, then all of the following are true:

5.2.1 E is locally ·valid· with respect to the ·governing type definition· as defined by Element Locally Valid (Type) (§3.3.4.4).

5.2.2 If D.{value constraint}.{variety} = fixed and E is not ·nilled· with respect to D, then all of the following are true:

5.2.2.1 E has no element information item [children].

5.2.2.2 The appropriate case among the following is true:

5.2.2.2.1 If E's ·governing type definition· is a Complex Type Definition with {content type}.{variety} = mixed , then the ·initial value· of E matches D.{value constraint}.{lexical form}.

5.2.2.2.2 If E's ·governing type definition· is a Simple Type Definition or a Complex Type Definition with {content type}.{variety} = simple, then the ·actual value· of E is equal or identical to D.{value constraint}.{value}.

so that's clear then.