Spell casting and paying costs timing

Let's say I can pay for a card's cost by discarding a card as an alternate casting cost.
Does any "When you cast this spell" trigger see the card in the graveyard??

I'm just trying to figure the exact timing.

If discarding is part of the spell cost, this must be paid to cast a spell. If the spell creates a trigger [at/when/whenever], the discards are in yard already.

Quote:

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Originally Posted by Fox

If discarding is part of the spell cost, this must be paid to cast a spell. If the spell creates a trigger [at/when/whenever], the discards are in yard already.

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Many thks.

If you want to see the order that stuff happens in while casting spells rule 601 goes over it in painstaking detail.

https://magic.wizards.com/en/game-in...-formats/rules