> > using the new language's compiler as the project compiler front end's drop-in replacement (without having to make any changes to the code at all for this first step)
I'll look into Zig more, though. Maybe I'll like it.
---
I stand corrected, given my phrasing. I should have specified that it needs to also support incrementally adding the new language's features while most of the code is still unaltered C, rather than (for instance) having to suddenly replace all the includes and function prototypes just because you want to add (in the case of Zig) an error "catch" clause.
This might come with huge drawbacks, but it still seems like the only socially acceptable way to fully replace C at this time; make it so you can replace it one line of code at a time in existing projects.
There are a few somewhat popular languages that fit that description already, and none of them are suitable replacements for C (as far as I've seen). That's not to say there couldn't be a suitable replacement -- just that nobody in a position to do something about it wants the suitable replacement enough for it to have emerged, apparently.
I suspect the first really suitable complete replacement for C would be something like what Checked C [1] tried to be, but a little more ambitious and willing to include wholly new (but perhaps backward-compatible) features (like some of those you've proposed) implemented in an interestingly new enough way to warrant a whole new compile-to-C implementation. Something like that could greatly improve the use cases where a true C replacement would be most appreciated, and still fit "naturally" into environments where C is already the implementation language of choice via a piecemeal replacement strategy where the first step is just using the new language's compiler as the project compiler front end's drop-in replacement (without having to make any changes to the code at all for this first step).
1: https://www.microsoft.com/en-us/research/project/checked-c/