Module storage_key 

Storage Key Computation Module

Computes deterministic storage keys for Neo N3 smart contract state variables, matching the layout actually emitted by the compiler’s bytecode (see src/cli/bytecode/bytecode_helpers/storage/mapping.rs).

Key Derivation (production scheme)

• Base slot of a state variable: SHA256(variable_name) — compute_state_slot. Struct fields use the same hash over the qualified "Struct::field" name (see src/ir/build/inference.rs).
• Mapping entry / dynamic-array element: derived ITERATIVELY per nesting level on-chain as slot = keccak256(StdLib.serialize(key) || slot), where serialize is Neo’s StdLib binary serializer applied to the canonicalized key stack item and the current slot is appended LAST. Dynamic arrays store their length at the base slot and element i at keccak256(serialize(i) || slot).
• Struct field inside a mapping value: keccak256(field_key || slot) where field_key = SHA256("Struct::field").

The mapping-entry derivation depends on Neo’s StdLib serialize native call (the serialized form embeds the stack-item type byte), so it cannot be reproduced faithfully off-chain without replicating Neo’s BinarySerializer byte-for-byte. A previous derive_mapping_slot / KeyFragment API in this module implemented a DIFFERENT, untyped SHA-256-based scheme that matched nothing the compiler emits; it has been removed so off-chain consumers cannot silently compute wrong keys.

Functions

compute_state_slot

Compute the canonical storage slot hash for a state variable name.