A compiler doesn't have to accept all possible programs. If it can't prove that a variable is initialized before being read, then it can simply require that you explicitly initialize it.
Not accepting many C programs, maybe. It's pretty easy to create a language where declaration is initialization of some sort, as evidenced by the large number of languages in common use where, one way or another, that's already the case.
This isn't some whacko far out idea. Most languages already today don't have any way (modulo "unsafe", or some super-carefully declared and defined method that is not the normal operation of the language) of reading uninitialized memory. It's only the residual C-likes bringing up the rear where this is even a question.
(I wouldn't count Odin's "explicitly label this as not getting initialized"; I'm talking about defaults being sharp and pointy. If a programmer explicitly asks for the sharp and pointy, then it's a valid choice to give it to them.)
I think we are in agreement? Odin works the way you describe, and GP in response expressed a preference that the compiler instead fail at compile time if it detected that memory had not been explicitly initialized; my response was to explain why this is not (in the general case) feasible.
It may not be feasible in the general case by changing the compiler, but it's definitely feasible in the general case by changing the language. If you can't specify an uninitialized variable syntactically then you don't have to analyze whether it exists semantically.
