Ask HN: What features or properties (from any language) are essential?

Without any particular religious One True Way(tm) flamewara, what do you expect in a modern statically-typed language?

- REPL/debugger?

- Package manager/TDD project watcher?

- C FFI without un/boxing?

- Gradual typing/type inference?

- Less punctuation?

- Shift-indentation blocks?

- GC or not to GC?

- Bare-metal executables / static libs?

- Opt-in duck-typing and mandatory interfaces?

- Capabilities?

- Compiler in C but mostly self-hosted?