Defensive Programming

Assertions verify invariants that must hold for the program to be correct. Choosing the right assertion type balances safety against runtime cost.

Use debug_assert for correctness-only checks (debug-assert)

Assertions verifying invariants that should never fail in correct code belong in debug_assert!, not assert!. debug_assert! is compiled out in release builds, so the check catches bugs during development without costing anything in production.

debug_assert!(self.align.is_multiple_of(PAGE_SIZE));
debug_assert!(self.align.is_power_of_two());

See also: std::debug_assert! and Rust Reference: debug_assertions.