Operator 'in' for collections

[jos3s]

It would be interesting to have the “in” operator as syntactic sugar for the “Contains” operation of collections

 if (collection.Contains(value)) {}

Instead of writing it as it is above, we would write it like this:

if (value in collection) {}

[HaloFour]

See: #420 #1665

[jos3s]

As far as I can see, none of these discussions have advanced since 2018/2019 or even analyzed the 'in' operator as 'Contains' as a possible initial version of their respective implementations

[chrisoverzero]

Exactly that was proposed in the final post to #1665. It didn't get traction.

[CyrusNajmabadi]

As far as I can see, none of these discussions have advanced since 2018/2019 or even analyzed the 'in' operator as 'Contains' as a possible initial version of their respective implementations

Correct. No one has been interested in advancing this.

[huoyaoyuan]

Also #4255 #5708, and something I replied much earlier but I can't find.

[Joe4evr]

As stated in the Framework Design Guidelines:

❌ DO NOT be cute when defining operator overloads.

I take that as also including proposing a currently non-existant operator for an operation that's already trivially achievable.