C. Statements

Back to Solidity Feature Support

Feature	Status	Notes
if / else	✅	Standard conditional branching.
for loop	✅	Init, condition, post, body all lowered.
while loop	✅	Condition + body.
do...while loop	✅	Body + condition.
break	✅	Loop break.
continue	✅	Loop continue.
return	✅	Single and multi-value returns.
emit Event(...)	✅	Maps to Runtime.Notify. Indexed params supported.
revert(...)	✅	Maps to NeoVM ABORT with message.
revert CustomError(...)	✅	Named revert with args.
Variable declaration	✅	Local variable definitions with optional initializer.
Block { ... }	✅	Scoped statement blocks.
unchecked { ... }	✅	Suppresses Solidity 0.8 checked-arithmetic guards inside the block; wrapping semantics are preserved for supported integer arithmetic.
assembly { ... }	⚠️	Limited Yul subset lowering; unsupported EVM-only operations warn and emit no assembly logic for that block.
try / catch	✅	Maps to NeoVM TRY/ENDTRY. Single catch clause preferred.
catch Error(string)	✅	Named catch with parameter binding.
catch Panic(uint256)	✅	Matches the EVM-canonical keccak256("Panic(uint256)")[..4] (= 0x4e487b71) selector on the revert envelope and decodes the 32-byte BE code into the catch binding (Task #103).
catch (bytes)	✅	Low-level catch with raw bytes.

Partial statement details

catch Panic(uint256) — The compiler emits the EVM-canonical revert envelope (selector || abi.encode(code)) for assert(false) (0x01), checked-arithmetic overflow and underflow (0x11), div/mod by zero (0x12), enum-cast range violations (0x21), empty-array .pop() (0x31), and abi.decode short-buffer faults (0x41). The catch Panic(uint code) dispatcher guards on the 4-byte selector and decodes code via StdLib.abiDecode, so panic codes such as 0x11 and 0x12 are reachable with Ethereum-compatible semantics.

unchecked { ... } — Checked arithmetic outside an unchecked block emits fixed-width range guards and reverts with Panic(0x11) on overflow or underflow. Inside unchecked, those overflow guards are suppressed and supported fixed-width arithmetic wraps according to Solidity semantics. unchecked does not suppress non-overflow panics such as division by zero (Panic(0x12)).

unchecked {
    uint256 result = a + b; // wraps instead of reverting on overflow
}

assembly { ... } — Inline assembly parses as Yul and lowers a compatibility subset for common library patterns: Yul locals and assignments, reads from Solidity locals and parameters, bounded mstore/mload/return, transient tstore/tload, returndatasize, guarded returndatacopy, arithmetic, bitwise, shift, comparison helpers, and simple nested control flow. EVM-only operations such as raw sload, sstore, call, and create should be rewritten with Solidity or Neo devpack/native-contract helpers.

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