Auto-complete for "".chars() and [""].join()


As a beginner, I'm trying to set up my environment. I found IntelliJ alone shows up the auto-complete for "string".chars() and [""].join() while emacs, vim, and VS Code(RLS and racer) don't. Could you kindly let me know why this is happening if you have any idea?

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You're probably using IntelliJ Rust for IntelliJ, which is its own plugin and doesn't use the RLS.


Yep, @ThomasdenH is correct. Currently, there are two and a half backends for doing IDE stuff for Rust.

  1. IntelliJ, which has a rust compiler frontend written in Kotlin
  2. Racer, a heuristics based lightweight code-completion tool
  3. RLS, which is the official tool, which uses both the compiler and Racer underneath. In particular, Racer is used for code completion, b/c compiler backend is not capable of that

Thus, all editors except IntelliJ use Racer for completion.


Yes, I'm using the IntelliJ Rust plugin. Thanks for this!

Very interesting to know. Thanks for this!