There are new languages with quite nice IDE support e.g. Swift or Kotlin.

anp · on March 3, 2016

Both of those examples are languages designed by IDE vendors, and their real IDE support comes from those vendors (Apple in the case of Swift, JetBrains in the case of Kotlin). It takes a bit longer when you can't just task an existing IDE development team to build your language support :). That said, I think that Rust has made fantastic progress towards IDE integrations so far.