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Use when writing Rust arithmetic on amounts or other quantities derived from external/user input — guard against silent overflow.
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Based on SOC occupation classification
> Use when this capability is needed.
Use when writing kernel, account, or note MASM code that reads from or writes to the advice provider (advice stack / advice map) — validate advice data.
Use when writing a Rust test that exercises a failure path or a MASM test that expects a `panic` / `assert` — assert on the specific expected error variant or error code.
Use when writing or reviewing MASM hot paths — prefer the cheaper equivalent instruction: `neq.0` over `gt.0` for non-zero checks, `cdrop` over an `if/else` selecting between two values, `dup.N` over `loc_load` for a value still on the stack, `eqw` over element-wise word comparison, `u32gt`/`u32lt` over generic `gt`/`lt` on known-u32 operands.
Use when naming a conversion or accessor method in Rust — follow the Rust API naming conventions for the method's cost and ownership.
Use when writing a MASM procedure inside a reusable account component that accesses account storage — receive the storage slot as a parameter so the component is portable across storage layouts.
| name | checked-arithmetic |
| description | Use when writing Rust arithmetic on amounts or other quantities derived from external/user input — guard against silent overflow. |
| metadata | {"author":"0xMiden"} |
Any arithmetic where one or more operands originates from external input (transaction body, advice provider, user RPC, deserialized payload) must use checked or overflowing arithmetic and surface the overflow:
checked_add / checked_sub / checked_mul and return an error on None.overflowing_add / widening_mul when you need the wrapping value and the overflow flag; then assert!(!overflow) (or branch) before using the result.+, -, * operators on untrusted values in release builds — debug-only overflow checks are not enough.The default +, -, * operators wrap silently in release builds, so an overflow on a balance or amount yields a wrong value with no error. Checked and overflowing operations surface the overflow so it can be rejected.
// Good: checked
let total = balance.checked_add(amount).ok_or(Error::Overflow)?;
// Good: overflowing with explicit flag check
let (product, overflow) = a.widening_mul(b);
if overflow { return Err(Error::Overflow); }
// Bad: wraps on overflow in release
let total = balance + amount;
Source: 0xMiden/protocol — distributed by TomeVault.