Rust’s built-in notion of safety is intentionally focused on memory + data-race properties at compile time. logic, timing, and determinism are left to libraries and design. Ada (with SPARK & Ravenscar) treats contracts, concurrency discipline, and timing analysis as first-class language/profile concerns hence a broader safety envelope.

You may choose to think from safety guarantee hierarchy perspective like (Bottom = foundation... Top = highest assurance)

Layer 6: FORMAL PROOFS (functional correctness, no RT errors) Ada/SPARK: built-in (GNATprove) Rust: external tools (Kani, Prusti, Verus)

Layer 5: TIMING / REAL-TIME ANALYSIS (WCET, priority bounds) Ada: Ravenscar profile + scheduling analysis Rust: frameworks (RTIC, Embassy)

Layer 4: CONCURRENCY DETERMINISM (predictable schedules) Ada: protected objects + task priorities Rust: data-race freedom; determinism via design

Layer 3: LOGICAL CONTRACTS & INVARIANTS (pre/post, ranges) Ada: Pre/Post aspects, type predicates (built-in) Rust: type states, assertions, external DbC tools

Layer 2: TYPE SAFETY (prevent invalid states) Ada: range subtypes, discriminants Rust: newtypes, enums, const generics

Layer 1: MEMORY SAFETY & DATA-RACE FREEDOM Ada: runtime checks; SPARK proves statically Rust: compile-time via ownership + Send/Sync