alt Hacker NewsC# is an odd one. It's surprisingly flexible, but then oddly lacking in other areas. Quite productive, but also quite inconsistent and uncomposable.
Once you've tried a better type system (Rust), it's difficult to go back to C#. People jump through all kinds of hoops to get good performance out of it, and they're mostly able to.
Things I dearly miss from Rust when I'm using C#:
- Associated types in interfaces. (IEnumerable should not be forced to return a type-erased = heap allocated IEnumerator instance.)
- Move-only structs. (Currently, every type with value semantics is trivially copyable, even ref structs.)
"IEnumerable should not be forced to return a type-erased = heap allocated IEnumerator instance."
Foreach loops use compile-time duck typing, so if you don't intend to use your enumerable in LINQ then both the enumerable and enumerator don't need to implement any interfaces.
This optimisation covers only one common use case, but that's the way of things in C# land.