> But what percentage of people who have "learned" C can actually write UB-free C with any reliability?
If your alternative is C and you really need the power of C and a guarantee of no UB, then by all means, (struggle to) learn Rust. But I would argue that limits Rust to very few niches of system/expert programming. The number of people who write these is very, very limited, hence the use of the language, tooling, libraries, etc.
The promise Rust makes nowadays is of an all around safe and productive language that can reward any effort spent fighting the type system and compiler with an error free execution.
For most programming tasks people use languages in the real world, I would say Rust fails to deliver on this, in the sense that the effort spent to master it and use it day to day only affords limited benefits. If you need to move fast and don't absolutely need the strongest reliability guarantees, then Rust is a tar-pit.
> If you need to move fast and don't absolutely need the strongest reliability guarantees, then Rust is a tar-pit.
That's true, but other type systems will likely fit your needs. For instance, if you're doing web, Elm's type system is head and shoulders above the more traditional options.
"Tar-pit" is overstating it significantly. It takes a paradigm shift, sure, but there are lots of options who feel Rust makes them more productive than other mainstream languages. A good type system can speed you up in some ways, too.
If your alternative is C and you really need the power of C and a guarantee of no UB, then by all means, (struggle to) learn Rust. But I would argue that limits Rust to very few niches of system/expert programming. The number of people who write these is very, very limited, hence the use of the language, tooling, libraries, etc.
The promise Rust makes nowadays is of an all around safe and productive language that can reward any effort spent fighting the type system and compiler with an error free execution.
For most programming tasks people use languages in the real world, I would say Rust fails to deliver on this, in the sense that the effort spent to master it and use it day to day only affords limited benefits. If you need to move fast and don't absolutely need the strongest reliability guarantees, then Rust is a tar-pit.