Choice of platform/web framework?

Question

Backend

Gentlemen, I'm interested in what kind of language / framework bundle now fits the requirements described below, the "freshness" or "old age" of the language does not really matter, we can advise at least those released this year.
Requirements.
1) Language + Framework should be easily navigable (go to definition) by source and all calls without the help of commercial IDEs, and with the help of some utilities over which plug-ins for editors / IDEs are already written. (as an example - racer for Rust, or all sorts of tools for Go).
2) Competitiveness is built into the language or platform, without additional left stray.
3) Lightness, which means the consumption of the minimum amount of resources needed to work on one node (and not consuming gigabytes just to start), i.e. ideally, if you run it on 1 cpu and 512 frames, then it should work (of course, there is no question of a super load here).
4) a normal package manager that will resolve dependencies on its own.
5) fast start or compilation without huge expectations.
6) well-designed testing tools. (cut as an example)
7) a more or less satisfactory ecosystem that would not have to _all_ write by hand.