the convention indeed does not encourage discipline, as @andir points
out[1], and at the worst would encourage haphazard changes because it
makes them appear harmless, as @tazjin adds [2].

[1]: https://github.com/NixOS/rfcs/pull/137/files#r1050542977
[2]: https://github.com/NixOS/rfcs/pull/137/files#r1050580213

as suggested by @piegamesde

as suggested by @infinisil and @kevincox

reworked the proposal to add semantics and combine it with related
efforts to provide a systematic way of issuing deprecation warnings.

prefer the special syntax approach, based on the arguments that all
other alternatives would defeat the purpose of guaranteeing predictable
results, which this proposal values higher than forward compatibility.

Co-authored-by: Ryan Lahfa <masterancpp@gmail.com>

Co-authored-by: sternenseemann <sternenseemann@systemli.org>

Co-authored-by: sternenseemann <sternenseemann@systemli.org>

Co-authored-by: sternenseemann <sternenseemann@systemli.org>

this is unrelated to the proposal, as the version declaration is only
relevant for parsing, and would cover all use cases of `langVersion` if
we have minor version numbers

Co-authored-by: piegames <account+github@piegames.de>

as discussed with @​roberth and @​piegamesde

Co-authored-by: Yorick van Pelt <yorick.vanpelt@tweag.io>