Cheatsheet

Order of Precedence of Operators

Neo DevPack for Solidity exactly mimics the Solidity operator precedence rules.

Global Variables Comparison

A quick reference for mapping EVM global context to NeoVM intrinsics:

For a guided, topic-by-topic version of these mappings, see Semantic Mapping.

EVM Global	NeoVM Equivalent	Notes
msg.sender	Runtime.getCallingScriptHash()	Accurate mapping.
msg.value	amount in onNEP17Payment	Only available during transfer hooks.
msg.data	selector || abi.encode(args)	In callbacks maps to typed data param; outside produces selector + encoded args.
msg.sig	Current function selector	Approximated; internal calls differ.
block.timestamp	Runtime.getTime()	Seconds since epoch.
block.number	Ledger.currentIndex()	Blockchain height.
block.coinbase	address(0)	dBFT has no miner.
block.sha3	Ledger.currentHash	Deprecated in Solidity 0.8+.
tx.origin	First signer hash	Not recommended for auth. Use witnesses.
this	Runtime.getExecutingScriptHash()	Accurate mapping.
address.balance	GAS.balanceOf(address)	Auto-mapped to GAS token.
address.transfer()	GAS.transfer(...)	Auto-mapped.
gasleft()	Runtime.gasLeft()	Execution GAS budget.

Cryptography Intrinsics

EVM Hash	Neo Native Contract Call
keccak256(data)	CryptoLib.keccak256(data)
sha256(data)	CryptoLib.sha256(data)
ecrecover(hash, v, r, s)	CryptoLib.recoverSecp256K1(...), then keccak256 + rightmost 20-byte address derivation

Security Best Practices

1. Authorization: Prefer Runtime.checkWitness(address) over msg.sender == address.
2. Wildcards: Always compile with --deny-wildcard-contracts and --deny-wildcard-methods for production to restrict the manifest.
3. Values: NeoVM stores integers as BigInteger, but Neo DevPack for Solidity emits Solidity 0.8 fixed-width overflow guards outside unchecked blocks. Use unchecked only when wraparound is intentional and tested.
4. Upgrades: Use ContractManagement.update() instead of Ethereum-style proxy contracts. Proxy storage delegates are not supported.