Something that Rust got _really_ right:
Editions. And not just that they exist, but that they are specified per module, and you can mix and match modules with different Editions within a bigger project. This lets a language make backwards incompatible changes, and projects can adopt the new features piecemeal.
If such a thing came to C++, there would obviously be limitations around module boundaries, when different modules used a different Edition. But perhaps this could be a way forward that could allow both camps to have their cake and eat it too.
Imagine a world where the main difference between Python 2 and 3 was the frontend syntax parser, and each module could specifically which syntax ("Edition") it used...
If such a thing came to C++, there would obviously be limitations around module boundaries, when different modules used a different Edition. But perhaps this could be a way forward that could allow both camps to have their cake and eat it too.
Imagine a world where the main difference between Python 2 and 3 was the frontend syntax parser, and each module could specifically which syntax ("Edition") it used...