Solidity v0.8.16 fixes an important bug.

The bug may result in small parts of dynamic tuple components being inadvertently zeroed during ABI re-encoding when the last component is a statically-sized uint or bytes32 calldata array. See Head Overflow Bug in Calldata Tuple ABI-Reencoding for more information.

Apart from that, there are several minor bug fixes and improvements like more gas-efficient overflow checks for addition and subtraction.

Full Changelog

Important Bugfixes:

  • Code Generation: Fix data corruption that affected ABI-encoding of calldata values represented by tuples: structs at any nesting level; argument lists of external functions, events and errors; return value lists of external functions. The 32 leading bytes of the first dynamically-encoded value in the tuple would get zeroed when the last component contained a statically-encoded array.

Compiler Features:

  • Code Generator: More efficient code for checked addition and subtraction.
  • TypeChecker: Support using library constants in initializers of other constants.
  • Yul IR Code Generation: Improved copy routines for arrays with packed storage layout.
  • Yul Optimizer: Add rule to convert mod(add(X, Y), A) into addmod(X, Y, A), if A is a power of two.
  • Yul Optimizer: Add rule to convert mod(mul(X, Y), A) into mulmod(X, Y, A), if A is a power of two.


  • Commandline Interface: Disallow the following options outside of the compiler mode: --via-ir,--metadata-literal, --metadata-hash, --model-checker-show-unproved, --model-checker-div-mod-no-slacks, --model-checker-engine, --model-checker-invariants, --model-checker-solvers, --model-checker-timeout, --model-checker-contracts, --model-checker-targets.
  • Type Checker: Fix compiler crash on tuple assignments involving certain patterns with unary tuples on the left-hand side.
  • Type Checker: Fix compiler crash when abi.encodeCall received a tuple expression instead of an inline tuple.
  • Type Checker: Fix null dereference in abi.encodeCall type checking of free function.

A big thank you to all contributors who helped make this release possible!

Download the new version of Solidity here: v0.8.16.