What are the Requirements of a spell?

Title says it all. I could find no guidance on what defines a requirement. 

An example- If you cast Wish to Inflict Wounds would you still have to touch the target?

Wish is the mightiest spell a mortal can cast. By simply speaking aloud, you can alter reality itself.

The basic use of this spell is to duplicate any other spell of level 8 or lower. If you use it this way, you don’t need to meet any requirements to cast that spell, including costly components. The spell simply takes effect.

The Wish spell very specifically says you don't need to meet ANY requirements. To my interpretation, that includes range, so I would say no, you would not need to touch someone if you use Wish to duplicate Inflict Wounds.

EDIT: However, I will defer to others who make a reasonable point that messing with the range or area would produce unexpected consequences.

(EDIT: for clarity)

Under my understanding, Casting Time and Components are requirements. A Spell Slot, if it's needed for a spell, is also a requirement to cast that spell.

Range limits the origin of the spell's effect, but technically, you can wait to choose the point of origin of an area of effect or your target(s) when you complete casting a spell (an example is when you Ready a spell; see related thread When casting a spell that takes longer than 1 action, when is the spell area, targets, and other spell choices defined?), so I don't consider it a requirement per se to cast a spell.

So, in your example, Wish bypasses Casting Time, Components, and the Spell Slot needed for the duplicated spell, but you should follow the Range rules for that duplicated spell as usual.

I disagree.

Range is not a requirement of a spell. Components and Concentration are. You do not need to provide components or Concentrate if the spell requires Concentration.

You cannot otherwise ignore basic parameters of the spell being replicated. You can't use Wish to circumscribe Faerun with a Lightning Bolt or completely cover the surface with the area of a Fireball.

Some spells may behave strangely if you completely ignore the requirements. For example, if a spell affects or interacts with a material component of the spell, not providing the material component may mean that there is nothing for the spell to affect.

EDIT: I agree with you, except for the Concentration part.

IMO, when the duplicated spell is cast, you must still maintain Concentration, not because it's a casting requirement (EDIT: I think it's not), but because it's necessary to sustain the spell's effect afterward:

Duration

A spell’s duration is the length of time the spell persists after it is cast. A duration typically takes one of the following forms:

Concentration. A duration that requires Concentration follows the Concentration rules (see the rules glossary). [...]

If it's useful for this discussion, here's a list of related threads from a recent conversation:

Quote from TarodNet >>

There are some threads about Wish or Divine Intervention that could be helpful here:

• is 【that】wish or the spell that wish duplicated?
• 2024 Cleric Level 10 Divine Intervention 
• Wish, concentration, and saves 
• Does Antimagic Field suppress spells cast by Divine Intervention? (or any magic made through Channel Divinity) 
• 2024 Divine Intervention & Counterspell 
• Question about Wish 
• Wish and it's repercussions

Quote from TarodNet>>

EDIT: I agree with you, except for the Concentration part.

IMO, when the duplicated spell is cast, you must still maintain Concentration, not because it's a casting requirement (EDIT: I think it's not), but because it's necessary to sustain the spell's effect afterward:

Yeah, I prefer that take actually. Just rushed a response after searching the spellcasting section for "require".

The requirements of a spell to my understanding are: (1) Preparation / Knowledge / Learning the spell and (2) the V,S,M components , as those are the requirements to cast the spell. Other things like concentration are required to sustain the spell which is different, where as range/targets/area are properties of the spell effect produced when you cast the spell.

You can absolutely cast Inflict Wound without there being a valid target within range, you can also concentrate on a spell while in an area of Antimagic or Silence where you cannot cast any spells. But generally you can't cast a spell if you don't have that spell prepared or don't have / cannot produce the required components. 

The only one I think is debatable is casting time, I think I would say that is time required to cast the spell thus Wish would circumvent those, but I could also see why DMs would rule it is a property of the spell. 

So I found this under Spells / Casting Spells / Components:

A spell’s components are physical requirements the spellcaster must meet to cast the spell. Each spell’s description indicates whether it requires Verbal (V), Somatic (S), or Material (M) components. If the spellcaster can’t provide one or more of a spell’s components, the spellcaster can’t cast the spell.

Are there non-physical requirements? If so, are they listed anywhere?

Quote from Zobar >>

So I found this under Spells / Casting Spells / Components:

A spell’s components are physical requirements the spellcaster must meet to cast the spell. Each spell’s description indicates whether it requires Verbal (V), Somatic (S), or Material (M) components. If the spellcaster can’t provide one or more of a spell’s components, the spellcaster can’t cast the spell.

Are there non-physical requirements? If so, are they listed anywhere?

I don't think they are called out as such, but to cast a spell you need to have it prepared (if it is level 1+) or known (cantrips). This usually also means that it must be on your class's spell list, but some feats and species provide alternatives.

Wish bypasses those requirements by explicitly allowing the effect of the spell to be replicating any spell less than 9th level. Basically, by casting Wish, you get the effects of another spell without casting that spell and so do not meet the requirements to cast that spell in addition to Wish.

Quote from Zobar >>

Title says it all. I could find no guidance on what defines a requirement. 

An example- If you cast Wish to Inflict Wounds would you still have to touch the target?

 Yes. If youWish to duplicate Inflict Wounds, while you don’t need to meet any requirements to cast it as it simply takes effect, the effect itself is that a creature you touch makes a Constitution saving throw, taking 2d10 Necrotic damage on a failed save or half as much damage on a successful one.

So you still need to touch it.

Quote from Zobar >>

So I found this under Spells / Casting Spells / Components:

A spell’s components are physical requirements the spellcaster must meet to cast the spell. Each spell’s description indicates whether it requires Verbal (V), Somatic (S), or Material (M) components. If the spellcaster can’t provide one or more of a spell’s components, the spellcaster can’t cast the spell.

Are there non-physical requirements? If so, are they listed anywhere?

 Non-physical ones are, to me, the ones I mentioned: Casting Time (EDIT: is this physical? :D) and Spell Slot (if needed). Also, as Agilemind said: "(1) Preparation / Knowledge / Learning the spell".

So those non-physical requirements, along with the Spell Components, should come before a spell's effect.

EDIT: uh... ninja'd by some adventurers...

There could be exception, for exemple spells like Clone refering to one of their spell component vessel as part of their effect may also be required.

Generally speaking, for those who do not consider casting the spell within range to be a requirement of the spell, are you saying that a spellcaster is actually allowed to attempt to cast the spell outside of that Range and you would then treat that as an Invalid Target?  Meaning, the action, spell slot, and other resources are expended?  Of course, this requires that you land on one side of the debate that choosing the point of origin is a form of "targeting", which not everyone agrees with.  And if you don't agree with that then how do you reconcile the idea that staying within range is not required and yet there seems to be no other rule that describes what might happen when the range parameter is violated?

For readying a spell or another action, does the target have to be in range?
Your target must be within range when you take a readied action, not when you first take the Ready action to ready it.

If a spellcaster is affected by slow and takes two turns to finish casting a spell, what happens if their target has moved out of range or out of sight?
You choose the targets of a spell when you complete casting a spell, not when you start. (slow)

There was also a similar discussion here: Can you ready an action and then take a bonus action? (see also the previous link I posted)

Quote from tarod_ >>

This was discussed before, but Range and Targets, while related, are different concepts. The target is part of the spell's effect, so it's not (normally) a requirement to cast a spell.

The 5e and 5.5e SAC have Q&A about when targeting happens:

For readying a spell or another action, does the target have to be in range?
Your target must be within range when you take a readied action, not when you first take the Ready action to ready it.

 

If a spellcaster is affected by slow and takes two turns to finish casting a spell, what happens if their target has moved out of range or out of sight?
You choose the targets of a spell when you complete casting a spell, not when you start. (slow)

There was also a similar discussion here: Can you ready an action and then take a bonus action? (see also the previous link I posted) 

There is an added layer of interaction between the two answers because of Ready: 

When you Ready a spell, you cast it as normal (expending any resources used to cast it) but hold its energy, which you release with your Reaction when the trigger occurs. To be readied, a spell must have a casting time of an action, and holding on to the spell’s magic requires Concentration, which you can maintain up to the start of your next turn. If your Concentration is broken, the spell dissipates without taking effect.

The second Sage Advice says you choose targets when you complete casting, not when you start (and not when you release the energy is implied). The first Sage Advice says that your target must be in range when you take the ready action (and complete casting the spell).

First, since the target needs to be in range only when the spell casting is complete, I don't the range is a spell casting requirement, it is an effect requirement and Wish does not bypass that.

Secondly, and more broadly applicable, readying an action to cast a spell (such as Inflict Wounds) when an enemy comes into range is not allowed by RAW. I would think that the target has to be in range when you release the spell.

(EDIT: fix grammar)

I agree with "it is an effect requirement and Wish does not bypass that" & "I would think that the target has to be in range when you release the spell"

Plague wrote some nice examples in that thread I mentioned:

Quote from Plaguescarred >>

To me RAW support SAC official ruling. When you ready a spell, you cast it as normal but hold its energy, which you release with your reaction when the trigger occurs. The rest of a spell entry describes the spell's effect. which is usually where the target is identified. In other words, target's choice is part of spell's effect when it materialize. For example;

When you ready web, only when you release it as a reaction that "You conjure a mass of thick, sticky webbing at a point of your choice within range. The webs fill a 20-foot cube from that point for the duration." 

When you ready magic missile, only when you release it as a reaction that "You create three glowing darts of magical force. Each dart hits a creature of your choice that you can see within range."

When you ready bless, only when you release it as a reaction that "You bless up to three creatures of your choice within range."

Casting a Spell: When a character casts any spell, the same basic rules are followed, regardless of the character's class or the spell's effects. Each spell description begins with a block of information, including the spell's name, level, school of magic, casting time, range, components, and duration. The rest of a spell entry describes the spell's effect.

I changed my position, and now agree that Wish should not bypass range or area, because those are really more like limitations than requirements.

Quote from Plaguescarred >>

There could be exception, for exemple spells like Clone refering to one of their spell component vessel as part of their effect may also be required.

 IMO this is like casting Control Water when there is no water within range - you can cast it but it doesn't necessarily work as described. Sure you can cast Clone with Wish without the vessel, but partially formed clone will just appear on the ground and immediately start dying. 

My question was not answered.  I am well aware of what Range and Targets mean when it comes to spellcasting.  My question is how are you generally ruling attempts to violate the Range parameter?

Example:

DM:  From around the corner of the hallway about 50 feet from you steps a goblin who fires his shortbow at you . . . and misses.  What do you do?

Player:  I cast Shocking Grasp on the goblin.

DM:  ???

Example 2:

DM:  Cresting up and over the mountaintop a quarter mile or so away you spot an enormous green dragon which begins flying in your direction.  What do you do?

Player:  I cast Magic Missile at the dragon.

DM:  ???

I've never really seen a game played where the DM just responds with something like:  "Ok, you cast the spell.  Your action is wasted and your spell slot is wasted."

Instead, I typically see the DM say something like "Well, that target is out of range.  Do you want to do something else instead?" 

Perhaps the first response is closer to the RAW than the second one, but only if you are actually applying the rule for Invalid Targets, which is questionable as I said before.  The second response essentially treats attempting to originate the effect within the range as a requirement of casting the spell in the first place.  That's how I normally see people play it, but my point is that I don't see a slam dunk rule for ruling this in either direction.  I also suspect that how some DMs run the above situations might be inconsistent with their insistence that legally selecting the point of origin is not a requirement for casting the spell.

A related question arises regarding the Clear Path rule.  To keep it simple, suppose you are casting a spell which clearly targets a single creature directly (not an AoE spell).  Say, Fire Bolt, for example.  It was fully described that the enemy has run behind a large brick wall and enjoys Total Cover from there.  The player declares that he casts Fire Bolt at that enemy.  This is also a case where the Invalid Targets rule does not really fit the scenario.  But if that's not the rule that we are using to justify a wasted action and wasted spell slot, then which rule are we pointing to when we say that such things are not requirements for actually casting the spell?  What is supposed to actually happen in these cases and where in the rules does it say so?