Draw replacement

[blaat]

The rule:

419.6h Some effects replace card draws. These effects are applied even if no cards could be drawn because there are no cards in the affected player's library. If an effect replaces a draw within a sequence of card draws, all actions required by the replacement are completed, if possible, before resuming the sequence. If an effect would have a player both draw a card and perform an additional action on that card, and the draw is replaced, the additional action is not performed on any cards that are drawn as a result of that replacement effect.

Now, I know exactly how the interaction works with Sylvan Library and lets say a Words of War.
But how does the replacement work for the following cards that have an additional effect?
I found to many different answers on the internets.

Merfolk Looter
Creature - Merfolk Rogue 1/1, 1U (2)
{T}: Draw a card, then discard a card.

If you replace the draw, do you still have to discard?


Riddlesmith
Creature - Human Artificer 2/1, 1U (2)
Whenever you cast an artifact spell, you may draw a card. If you do, discard a card.

If you play a random artifact and replace the draw, do you have to discard (note the "if you do" clause)?


Brainstorm
Instant, U (1)
Draw three cards, then put two cards from your hand on top of your library in any order.

10/4/2004: This is all one effect. You draw 3 and return 2 cards all in one resolution. Nothing may happen between the two. If something triggers on drawing cards, it will go on the stack after Brainstorm finishes resolving.

How does it work here? (I already know you have to put 2 cards back anyway if you replace 1 or all of those draws, but please explain :) )

[Malchar]

Merfolk Looter
Creature - Merfolk Rogue 1/1, 1U (2)
{T}: Draw a card, then discard a card.

If you replace the draw, do you still have to discard?


You still have to discard a card, because the second part of the action isn't affecting the card drawn. If it said, draw a card, then discard that card, then you wouldn't have to discard if you replaced the draw. This is still true even if you don't have any cards in hand so that the card you draw must be the one discarded, of course, in this case, it doesn't really matter anyway.



Riddlesmith
Creature - Human Artificer 2/1, 1U (2)
Whenever you cast an artifact spell, you may draw a card. If you do, discard a card.

If you play a random artifact and replace the draw, do you have to discard (note the "if you do" clause)?

No, because it says "if you do", just like Sylvan Library iirc.



Brainstorm
Instant, U (1)
Draw three cards, then put two cards from your hand on top of your library in any order.

10/4/2004: This is all one effect. You draw 3 and return 2 cards all in one resolution. Nothing may happen between the two. If something triggers on drawing cards, it will go on the stack after Brainstorm finishes resolving.

How does it work here? (I already know you have to put 2 cards back anyway if you replace 1 or all of those draws, but please explain :) )

The 2004 "ruling" is misleading. It just means that you can't play spells or activate abilities in between. For example, you can't draw three cards, play everything in your hand, then have nothing to put back on top. If you replace the brainstorm draws, you just do it dynamically like with any other replaced draw. For example, if you had words of war replacing one draw, you would deal two damage, draw two, then put two back.

[cdr]

The part of the rule you underlined is to cover cards like Sindbad that specifically refer to the card drawn.


Sindbad 1U
Creature - Human
{T}: Draw a card and reveal it. If it isn't a land card, discard it.
1/1

The "reveal it and if it isn't a land card discard it" almost certainly won't make sense when the draw is replaced, so you don't do it (even if the draw is replaced by a draw).

[luma]

No, because it says "if you do", just like Sylvan Library iirc.

Wrong. If you replace the draw from Riddlesmith, you still have to discard a card. The "if you do" refers to choosing to draw a card (even if that draw was replaced with something else). Sylvan Library works the same way: if you replace one or both of the draws with something else, you still have to choose two cards drawn that turn (or as many as you can if you don't have two) and put them back or pay life.

EDIT: here's the relevant rule:

117.12. Some spells, activated abilities, and triggered abilities read, "[Do something]. If [a player] [does or doesn't], [effect]." or "[A player] may [do something]. If [that player] [does or doesn't], [effect]." The action [do something] is a cost, paid when the spell or ability resolves. The "If [a player] [does or doesn't]" clause checks whether the player chose to pay an optional cost or started to pay a mandatory cost, regardless of what events actually occurred.