My upthread off-the-top-of-my-head idea was to have the compiler infer them and write them to a shadow file. I posited we can still see them in an IDE (toggle) and/or in error messages. So I posited we would only have to write them when we need to overrule the inference or when inference is undecideable (and then the can be removed after compiling because written to the shadow file). I am not arguing that is a good idea. I am just trying to figure out if what Rust is now is best, and for which use cases it is best fit.
My thought is that most of the time I don't want to look at or think about that detail. The inference could probably be good enough 80% of the time perhaps. I am prioritizing looking at the other semantics of my code. But maybe I am mistaken, because maybe I am thinking about how when I code only my innermost performance routines in C, I am always passing in borrowed pointer to a C function which doesn't leak any references, so I don't even need to think about it. And in other code (ever since using C++ with refcounting for the last time in 2002), I have been using a GC so I didn't have to think about it.
Perhaps this is related to my point that what probably or perhaps dominates the asymptotic memory performance of 80+% of my code is avoiding the type of "memory leaks" that can occur with both Rust's checked lifetimes and GC. I just can't imagine writing a mobile game (speed not a major factor, i.e. not 3D), word processing, or other productivity app with such coding precision that the entire body of code is compile-time checked manual memory mgmt (although I did ref counting for my last C++ app finished in 2002). Instead I would write most of the code employing GC and then the critical parts that need to be super fast I would write in C as stated above.
Thus for me, I envision a language that combined high level and low level coding, would allow me to write my "C" code in the same language, but still alllow me to use GC for most of my code. What aggravates me about managed languages such as Java, JS, is I have to switch to a FFI and other language to write the performance bits of code. I would prefer it was all unified if that makes sense.
Yet I am also paying attention to what others say here and trying to relate it to my experience. So I am still trying to for a clear analysis of what I want and for which use cases. I realize there are other use cases where perhaps different priorities and patterns apply.
Afair most of my code is not passing Copy types. Seems boxes are the norm, except in some requirement for highly performant (lower-level) homogeneous (or hetereogenous via enum) arrays and vectors.
I'm eager to read different perspectives.
Edit: if asymptotic "memory leaks" is the main culprit to attack (thus Rust's lifetimes wouldn't fix it), perhaps for example the browser should isolate memory partitions for each tab open in my browser and kill tabs that are overconsuming when GC starts thrashing instead of locking up my entire Linux desktop as Firefox does now. And it is probably all that adware bloat scripting that google et al dump on every web page with advertising.