IntelliJ IDEA Rust plugin gives all of that, although sometimes types detection is not smart enough.
I've been using this plugin but it doesn't seem to do auto-import. Does it definitely support that? Apart from that, as you say, type detection isn't always particularly useful. Apart from those two features, it's pretty much there, definitely usable.
Most Java/C# IDEs will get you:
- Type-based autocomplete (racer/YCM/etc have this for Rust)
- Jump-to-definition / documentation (YCM/etc has this)
- Autoimport
- Non-grep-based refactoring
- Auto-boilerplating: for example, type `impl Trait for MyType` and have it tab-complete to a skeleton trait impl
- Some error integration (not just fileline jump-to), with tooltips and stuff asking you how you want the IDE to auto-fix the error
- A bunch of other smaller useful things which I can't remember at the moment
Now, autocomplete is a major chunk of this, but nowhere near being all of it.
The way I see it there are two camps on this issue. There's the "text editor" camp who use vim/emacs/sublime and when they are asking for IDE support they just mean autocomplete and jump-to that works from their editor. Then there's the camp coming from Eclipse or VS who want the whole deal.
The Rust Language Server project (https://github.com/jonathandturner/rls) is working on exposing this info from the compiler in a structured form so that IDEs and "text editor"s alike can get IDE features.