Treat as Improvised Weapons
Using a ranged weapon as a Melee weapon activates the Improvised Weapons rules (emphasis mine):
If a character uses a ranged weapon to make a melee attack, or throws a melee weapon that does not have the thrown property, it also* deals 1d4 damage. (PHB p. 147)
Because it's purely improvised, it wouldn't utilize any of the other properties of the actual item (such as the Net's Restrained condition.)
*This is referring to the earlier sentence, equating the damage a ranged weapon used in melee to an object that has no resemblance to a weapon:
An object that bears no resemblance to a weapon deals 1d4 damage.
Is it a melee weapon or a ranged weapon?
The weapons table (PHB, 149) lists which weapons or Melee vs Ranged. Some melee weapons have a Thrown property which allows them to be used as Ranged weapons, but no Ranged weapons have a property that allows them to be used a Melee weapons. If it doesn't doesn't state you can use as both, then whatever isn't listed becomes an improvised weapon attack. This is from the Weapons description on page 146 (emphasis mine):
Every weapon is classified as either melee or ranged. A melee weapon is used to attack a target within 5 feet of you, whereas a ranged weapon is used to attack a target at a distance.
The absence of a mechanic for allowing a Ranged Weapon to be used in Melee turns the use of that weapon into an Improvised Weapon.
Mechanic for using Ranged while within Melee
There does exist a mechanic for using a ranged weapon in Melee range: Disadvantage. See Page 195 of the PHB for Ranged Attacks in Close Combat:
Aiming a ranged attack is more difficult when a foe is next to you. When you make a ranged attack with a weapon, a spell, or some other means, you have
disadvantage on the attack roll if you are within 5 feet of a hostile creature who can see you and who isn’t incapacitated.
This is supported by Jeremy Crawford
On twitter, he stated
If you use a weapon in a way that turns it into an improvised weapon—such as smacking someone with a bow—that weapon has none of its regular properties, unless the DM rules otherwise.