Rust Ownership Explained: Copy Trait, Value Drop, and Drop Order

Rust's memory model enforces a single-owner rule for every value, managed by the borrow checker, which ensures each value is freed exactly once. When a value is assigned to a new location, ownership transfers via a move, unless the type implements the Copy trait, which allows a bitwise duplication instead. Types like Box cannot implement Copy because doing so would cause two variables to claim ownership of the same heap memory, leading to a double-free error. When a value goes out of scope, Rust automatically drops it along with any values it owns, recursively freeing nested data. Variables are dropped in reverse order of declaration, while nested values within a type are dropped in source order.