Rules-modifying effects prohibiting spell casting need to be updated

[awjackson]

The rules for "Players can't cast {quality} spells" have changed several times over the last decade and xmage currently implements a mishmash of several outdated versions of them. Two concrete examples:

• Effects that say "Players can't cast creature spells" should still allow a player to cast a spell with bestow in its Aura mode, and conversely effects that say "Players can't cast noncreature spells" should prevent players from casting bestow spells as Auras. Currently xmage always treats the spell as a creature spell. This rule was changed in 2015, with the release of Magic Origins. [edit: this was fixed by Morph rework and check spell characteristics #11178]
• Conversely, if an effect says players can't cast spells with a certain name, a player should not even be able to begin the spell casting process unless there is some choice they could make that would change the spell's name (e.g. it is an MDFC, a card with disturb in their graveyard, or a card with morph cast face down so it has no name). xmage allows them to put the spell onto the stack and only checks legality after it is on the stack, which was how the rules worked between 2015 and 2018 (the rule was changed shortly after the release of Dominaria to "fix" the admittedly flavorful but bizarre and counterintuitive interaction between [[Ixalan's Binding]] and [[Squee, the Immortal]]).

[github-actions]

Ixalan's Binding - (Gatherer) (Scryfall) (EDHREC)

{3}{W}
Enchantment
When Ixalan's Binding enters the battlefield, exile target nonland permanent an opponent controls until Ixalan's Binding leaves the battlefield.
Your opponents can't cast spells with the same name as the exiled card.

Squee, the Immortal - (Gatherer) (Scryfall) (EDHREC)

{1}{R}{R}
Legendary Creature — Goblin
2/1
You may cast Squee, the Immortal from your graveyard or from exile.