I'm just glad that overall there is a general support to a view that is a reasonable one, i.e. not adding a cantrip damage that scales with level to haste, when the spell is clearly designed NOT to scale.
This is obviously false on its face. The single haste attack clearly works with other attacks that scale, Like a Paladin's smite, a Warlocks Smite, or a Rogue's sneak attack.
A rogue specifically can hold their action till some other trigger (IE it isn't my turn anymore or right after ally X goes), so they can sneak attack twice per game round, by using their haste attack to also get sneak attack.
Why should the melee wizard be the only class specifically blocked from benefitting in this way?
This is the danger of a RAI rather than RAW(with some reasonable exceptions).
Moreover ( ;) ), the wording for the cantrip in place of an attack is different sentence to the granting of an additional attack.
You can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks.
Moreover is defined: as a further matter; besides.
It seems very clear based on the language used that the cantrip in place of one attack during an attack action is not linked directly to having to be able to take more than one attack during said attack action.
All of this said, play your games however you'd like.
For me the debate isn't really about if the Bladesinger cantrip attack can't replace a attack if it's only one attack, it's a matter of which is more specific, Haste's one weapon attack restriction or Bladesinger's Extra Attack.
I say Haste is more specific, since it's a temporary spell while Bladesinger Extra Attack is always on (and nobody is ever going to argue that Extra Attack is more specific than Haste's one weapon attack, so why disallow that while allowing the second part to work), but I admit it is very debatable as both alter the Attack action.
It is true that martial attacks do tend to scale (not just resource heavy attacks like smites, stuff like Barbarian rage, weapon feats, and stuff like Fighting styles would of been much examples), however I would argue Bladesinger attacks can already scale considering the bladesinger capstone, spells like Shadowblade (which would require someone else cast Haste but that also applies to most martials anyways) and that Bladesingers don't need additional buffs.
Edit: Changed some wording since i realize this is my opinion which might not be the majority.
You can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks.
Moreover is defined: as a further matter; besides.
It seems very clear based on the language used that the cantrip in place of one attack during an attack action is not linked directly to having to be able to take more than one attack during said attack action.
All of this said, play your games however you'd like.
And yet. By the words that you put on the screen talking about it. It is directly Linked to that. Because that Moreover which your sayind is a further matter. Means it is an additional condition that you have to meet. Your even showing this by giving us the basic definition of moreover. Which in the context of that sentence means "As a Further Matter" which is quite litterally and Exactly:
"you can cast one of your cantrips in place of one of those attacks."
which is directly linking that not only do you have to be using the Attack Action but you further have to be using it under it's Proper condition of being specifically One of the Attacks of that Attack Action that your getting from the first part of the ability which is to take 2 attacks for the one action that you are getting. The reason is because that Further Matter Specifically references back to the First Matter essentially by the word "THOSE ATTACKS" which is referencing back to the first part of the ability where you are getting them in the first place.
Let us not argue about specific wording. 5E was not designed with that in mind, the developers didn't put any thought into what "Moreover" means other than it sounded like it would fit. Arguing semantics in a game that is against semantics will only cause confusion.
Based on what I’m seeing, the extra attack granted by haste can be replaced with a cantrip.
The thing is, this is not an extra attack. This is its only action separate from the extra attack feature. In the spell, it specifically states what you may do with the action. It does not state you can cast a spell with the action, nor does it say that this action is considered an extra attack. So no it can't be replaced with a cantrip.
Based on what I’m seeing, the extra attack granted by haste can be replaced with a cantrip.
The thing is, this is not an extra attack. This is its only action separate from the extra attack feature. In the spell, it specifically states what you may do with the action. It does not state you can cast a spell with the action, nor does it say that this action is considered an extra attack. So no it can't be replaced with a cantrip.
This.
The haste is crystal clear that the extra "Attack (one weapon attack only)" cannot be combined with anything else. This includes the casting of a spell; even if that spell includes a weapon attack like booming blade.
Based on what I’m seeing, the extra attack granted by haste can be replaced with a cantrip.
The thing is, this is not an extra attack. This is its only action separate from the extra attack feature. In the spell, it specifically states what you may do with the action. It does not state you can cast a spell with the action, nor does it say that this action is considered an extra attack. So no it can't be replaced with a cantrip.
This.
The haste is crystal clear that the extra "Attack (one weapon attack only)" cannot be combined with anything else. This includes the casting of a spell; even if that spell includes a weapon attack like booming blade.
To Clear up what Jounichi is saying slightly. The action from haste is it's own action. It is not an Extra anything. It's very specific in how that action can be used over-ruling anything that doesn't fit within the limits that it places and even specifying that the Attack Action which Extra Attack usually modifies cannot be modified by it and that it can't be used in any other way than the single weapon attack even though it normally has somewhat broader usage.
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
Just to clear up, I think the matter is rather unclear as to intent, and anyone claiming to "know" definitively is just advocating for what they want.
My post primarily was to push back on the idea that "the (special) attack action granted by haste isn't designed to scale" Which is obviously not true. Using that argument to deny the cantrip attack to a bladesinger specifically, is nonsense.
I personally think it works, I am also not really that worried about it. Talk about it with your DM. I think that the restriction on the haste attack was just to clarify that it was a single attack, and not something more complicated. To me, getting a second booming blade while concentrating on haste just allows a different option, if you just want more pamlocks, w/e that is your call.
This is a very specific ability for 1 subclass. We know the numbers here, does anything think that being able to do 2 booming blades a turn as a melee wizard is "too powerful" or "unbalanced"?
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
Yes it is. Booming blade is a spell. As part of the spell you make a weapon attack, but you are still using the "Cast a Spell" action, not the "Attack" action. So no, you cannot use the Haste action to cast Booming Blade.
Look to Chapter 9 of the player's handbook under Actions in Combat to see the difference.
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
Yes it is. Booming blade is a spell. As part of the spell you make a weapon attack, but you are still using the "Cast a Spell" action, not the "Attack" action. So no, you cannot use the Haste action to cast Booming Blade.
Look to Chapter 9 of the player's handbook under Actions in Combat to see the difference.
Basically what Gamer said. But it is called out specifically that an Attack during a spell is not taking the Attack Action. That's actually covered both under the Actions in Combat Section and the Chapter on Casting Magic.
Also "Attack with Weapon" is not an action. It's simply the Attack Action. which actually covers more than just weapons. But it is specifically called out as being separate and different from the "Cast a Spell" action.
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
Yes it is. Booming blade is a spell. As part of the spell you make a weapon attack, but you are still using the "Cast a Spell" action, not the "Attack" action. So no, you cannot use the Haste action to cast Booming Blade.
Look to Chapter 9 of the player's handbook under Actions in Combat to see the difference.
Booming Blade is a spell. I know of no rule which says that a spell whose casting requires attacking with a weapon doesn't count as "attacking with a weapon" in addition to counting as "casting a spell."
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
Yes it is. Booming blade is a spell. As part of the spell you make a weapon attack, but you are still using the "Cast a Spell" action, not the "Attack" action. So no, you cannot use the Haste action to cast Booming Blade.
Look to Chapter 9 of the player's handbook under Actions in Combat to see the difference.
Booming Blade is a spell. I know of no rule which says that a spell whose casting requires attacking with a weapon doesn't count as "attacking with a weapon" in addition to counting as "casting a spell."
Haste gives you an Action that you can use. This Action is special because it is limited in what the action can be used for. You cannot use this Action to Cast a Spell. You CAN use the Action to take the Attack Action but it is limited to a single weapon attack. "Attacking with a weapon" isn't an action that is listed for Haste.
So you are wrong in your argument and Booming Blade may not be used with Haste
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
Yes it is. Booming blade is a spell. As part of the spell you make a weapon attack, but you are still using the "Cast a Spell" action, not the "Attack" action. So no, you cannot use the Haste action to cast Booming Blade.
Look to Chapter 9 of the player's handbook under Actions in Combat to see the difference.
Booming Blade is a spell. I know of no rule which says that a spell whose casting requires attacking with a weapon doesn't count as "attacking with a weapon" in addition to counting as "casting a spell."
Haste gives you an Action that you can use. This Action is special because it is limited in what the action can be used for. You cannot use this Action to Cast a Spell. You CAN use the Action to take the Attack Action but it is limited to a single weapon attack. "Attacking with a weapon" isn't an action that is listed for Haste.
So you are wrong in your argument and Booming Blade may not be used with Haste
Haste states, "That action can be used only to take the Attack (one weapon attack only) etc."
Booming Blade states, "You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you." That is what it takes to cast the spell - you need to make an Attack action (one weapon attack only) THAT's the casting action.
So, while you are welcome to your opinion, I do not believe it is as settled an issue as you think it is.
Haste states, "That action can be used only to take the Attack (one weapon attack only) etc."
Booming Blade states, "You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you." That is what it takes to cast the spell - you need to make an Attack action (one weapon attack only) THAT's the casting action.
So, while you are welcome to your opinion, I do not believe it is as settled an issue as you think it is.
I don't see Booming Blade mentioned at all as equipment or some special type of attack under the attack rules in the PHB, but it is in the list of cantrips. I wonder if that means it is a spell?
This is obviously false on its face. The single haste attack clearly works with other attacks that scale, Like a Paladin's smite, a Warlocks Smite, or a Rogue's sneak attack.
A rogue specifically can hold their action till some other trigger (IE it isn't my turn anymore or right after ally X goes), so they can sneak attack twice per game round, by using their haste attack to also get sneak attack.
Why should the melee wizard be the only class specifically blocked from benefitting in this way?
This is the danger of a RAI rather than RAW(with some reasonable exceptions).
Moreover ( ;) ), the wording for the cantrip in place of an attack is different sentence to the granting of an additional attack.
Moreover is defined: as a further matter; besides.
It seems very clear based on the language used that the cantrip in place of one attack during an attack action is not linked directly to having to be able to take more than one attack during said attack action.
All of this said, play your games however you'd like.
For me the debate isn't really about if the Bladesinger cantrip attack can't replace a attack if it's only one attack, it's a matter of which is more specific, Haste's one weapon attack restriction or Bladesinger's Extra Attack.
I say Haste is more specific, since it's a temporary spell while Bladesinger Extra Attack is always on (and nobody is ever going to argue that Extra Attack is more specific than Haste's one weapon attack, so why disallow that while allowing the second part to work), but I admit it is very debatable as both alter the Attack action.
It is true that martial attacks do tend to scale (not just resource heavy attacks like smites, stuff like Barbarian rage, weapon feats, and stuff like Fighting styles would of been much examples), however I would argue Bladesinger attacks can already scale considering the bladesinger capstone, spells like Shadowblade (which would require someone else cast Haste but that also applies to most martials anyways) and that Bladesingers don't need additional buffs.
Edit: Changed some wording since i realize this is my opinion which might not be the majority.
if I edit a message, most of the time it's because of grammar. The rest of the time I'll put "Edit:" at the bottom.
And yet. By the words that you put on the screen talking about it. It is directly Linked to that. Because that Moreover which your sayind is a further matter. Means it is an additional condition that you have to meet. Your even showing this by giving us the basic definition of moreover. Which in the context of that sentence means "As a Further Matter" which is quite litterally and Exactly:
"you can cast one of your cantrips in place of one of those attacks."
which is directly linking that not only do you have to be using the Attack Action but you further have to be using it under it's Proper condition of being specifically One of the Attacks of that Attack Action that your getting from the first part of the ability which is to take 2 attacks for the one action that you are getting. The reason is because that Further Matter Specifically references back to the First Matter essentially by the word "THOSE ATTACKS" which is referencing back to the first part of the ability where you are getting them in the first place.
Let us not argue about specific wording. 5E was not designed with that in mind, the developers didn't put any thought into what "Moreover" means other than it sounded like it would fit. Arguing semantics in a game that is against semantics will only cause confusion.
if I edit a message, most of the time it's because of grammar. The rest of the time I'll put "Edit:" at the bottom.
Based on what I’m seeing, the extra attack granted by haste can be replaced with a cantrip.
The thing is, this is not an extra attack. This is its only action separate from the extra attack feature. In the spell, it specifically states what you may do with the action. It does not state you can cast a spell with the action, nor does it say that this action is considered an extra attack. So no it can't be replaced with a cantrip.
This.
The haste is crystal clear that the extra "Attack (one weapon attack only)" cannot be combined with anything else. This includes the casting of a spell; even if that spell includes a weapon attack like booming blade.
To Clear up what Jounichi is saying slightly. The action from haste is it's own action. It is not an Extra anything. It's very specific in how that action can be used over-ruling anything that doesn't fit within the limits that it places and even specifying that the Attack Action which Extra Attack usually modifies cannot be modified by it and that it can't be used in any other way than the single weapon attack even though it normally has somewhat broader usage.
I erred.
I'd like to change my position
the Bladesinger ability states, "Starting at 6th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks."
Which attacks can be replaced with cantrips? Answer, "one of those attacks?" What are "those attacks"? Answer, the attacks granted at 6th level. So, not the spells granted by Haste.
That having been said, if I were GM, I'd probably allow the attacks granted by the Haste spell to be replaced with cantrips by Bladesingers of at least sixth level. That just isn't RAW. It is based on the Rule of Cool.
That having been said,
Haste states, "That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Use an Object action."
The attack from Haste can be done with a spell which functions as a weapon, such as Shadow Blade (assuming the spell was already cast). I also am not yet convinced that it wouldn't permit Booming Blade.
The spell shadow blade also creates a simple melee weapon with which the spellcaster can make a melee weapon attack.
Booming Blade is Cast a spell. This is an important distinction that you've already covered by saying "Assuming the Spell was already Cast." Shadow Blade once it's already cast is just a weapon in your hand and you use use the Attack Action to make attacks with it. Booming Blade despite having a weapon attack involved never uses the Attack Action. it uses the cast a spell action. The weapon attack in it is purely part of the spell and not actually some kind of action on it's own.
Just to clear up, I think the matter is rather unclear as to intent, and anyone claiming to "know" definitively is just advocating for what they want.
My post primarily was to push back on the idea that "the (special) attack action granted by haste isn't designed to scale" Which is obviously not true. Using that argument to deny the cantrip attack to a bladesinger specifically, is nonsense.
I personally think it works, I am also not really that worried about it. Talk about it with your DM. I think that the restriction on the haste attack was just to clarify that it was a single attack, and not something more complicated. To me, getting a second booming blade while concentrating on haste just allows a different option, if you just want more pamlocks, w/e that is your call.
This is a very specific ability for 1 subclass. We know the numbers here, does anything think that being able to do 2 booming blades a turn as a melee wizard is "too powerful" or "unbalanced"?
It is not at all clear that Booming Blade doesn’t belong to both “attack with weapon” as well as “cast a spell” groups.
Yes it is. Booming blade is a spell. As part of the spell you make a weapon attack, but you are still using the "Cast a Spell" action, not the "Attack" action. So no, you cannot use the Haste action to cast Booming Blade.
Look to Chapter 9 of the player's handbook under Actions in Combat to see the difference.
Basically what Gamer said. But it is called out specifically that an Attack during a spell is not taking the Attack Action. That's actually covered both under the Actions in Combat Section and the Chapter on Casting Magic.
Also "Attack with Weapon" is not an action. It's simply the Attack Action. which actually covers more than just weapons. But it is specifically called out as being separate and different from the "Cast a Spell" action.
Booming Blade is a spell. I know of no rule which says that a spell whose casting requires attacking with a weapon doesn't count as "attacking with a weapon" in addition to counting as "casting a spell."
Haste gives you an Action that you can use. This Action is special because it is limited in what the action can be used for. You cannot use this Action to Cast a Spell. You CAN use the Action to take the Attack Action but it is limited to a single weapon attack. "Attacking with a weapon" isn't an action that is listed for Haste.
So you are wrong in your argument and Booming Blade may not be used with Haste
Haste states, "That action can be used only to take the Attack (one weapon attack only) etc."
Booming Blade states, "You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you." That is what it takes to cast the spell - you need to make an Attack action (one weapon attack only) THAT's the casting action.
So, while you are welcome to your opinion, I do not believe it is as settled an issue as you think it is.
I don't see Booming Blade mentioned at all as equipment or some special type of attack under the attack rules in the PHB, but it is in the list of cantrips. I wonder if that means it is a spell?
How about you point out to me any rule which says that casting a cantrip cannot be an attack? That'd be helpful.