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@chriseth chriseth released this Apr 17, 2018 · 4419 commits to release since this release

This release features several major and long-awaited changes:

  • It is now possible to access dynamic data (arrays, strings, etc) returned by function calls.
  • You can specify error reason strings for revert and require (support by tooling is still pending).
  • We added the global functions abi.encode(), abi.encodePacked(), abi.encodeWithSelector() and abi.encodeWithSignature() which expose the ABI encoding functions and each return a bytes value.
  • Constructors should now be defined using constructor(uint arg1, uint arg2) { ... } to make them stand out and avoid bugs when contracts are renamed but not their constructors.
  • Some array operations got cheaper, especially the push function and initialization of memory arrays.

If you want to perform a source build, please only use solidity_0.4.22.tar.gz and not the zip provided by github directly.


  • Code Generator: Initialize arrays without using msize().
  • Code Generator: More specialized and thus optimized implementation for x.push(...)
  • Commandline interface: Error when missing or inaccessible file detected. Suppress it with the --ignore-missing flag.
  • Constant Evaluator: Fix evaluation of single element tuples.
  • General: Add encoding routines abi.encodePacked, abi.encode, abi.encodeWithSelector and abi.encodeWithSignature.
  • General: Add global function gasleft() and deprecate msg.gas.
  • General: Add global function blockhash(uint) and deprecate block.hash(uint).
  • General: Allow providing reason string for revert() and require().
  • General: Allow and recommend new constructor syntax using the constructor keyword (generate error as experimental 0.5.0 feature).
  • General: Limit the number of errors output in a single run to 256.
  • General: Support accessing dynamic return data in post-byzantium EVMs.
  • Inheritance: Error when using empty parentheses for base class constructors that require arguments as experimental 0.5.0 feature.
  • Inheritance: Error when using no parentheses in modifier-style constructor calls as experimental 0.5.0 feature.
  • Interfaces: Allow overriding external functions in interfaces with public in an implementing contract.
  • Optimizer: Optimize SHL and SHR only involving constants (Constantinople only).
  • Optimizer: Remove useless SWAP1 instruction preceding a commutative instruction (such as ADD, MUL, etc).
  • Optimizer: Replace comparison operators (LT, GT, etc) with opposites if preceded by SWAP1, e.g. SWAP1 LT is replaced with GT.
  • Optimizer: Optimize across mload if msize() is not used.
  • Static Analyzer: Error on duplicated super constructor calls as experimental 0.5.0 feature.
  • Syntax Checker: Issue warning for empty structs (or error as experimental 0.5.0 feature).
  • Syntax Checker: Warn about modifiers on functions without implementation (this will turn into an error with version 0.5.0).
  • Syntax Tests: Add source locations to syntax test expectations.
  • Type Checker: Improve documentation and warnings for accessing contract members inherited from address.


  • Code Generator: Allow block.blockhash without being called.
  • Code Generator: Do not include internal functions in the runtime bytecode which are only referenced in the constructor.
  • Code Generator: Properly skip unneeded storage array cleanup when not reducing length.
  • Code Generator: Bugfix in modifier lookup in libraries.
  • Code Generator: Implement packed encoding of external function types.
  • Code Generator: Treat empty base constructor argument list as not provided.
  • Code Generator: Properly force-clean bytesXX types for shortening conversions.
  • Commandline interface: Fix error messages for imported files that do not exist.
  • Commandline interface: Support --evm-version constantinople properly.
  • DocString Parser: Fix error message for empty descriptions.
  • Gas Estimator: Correctly ignore costs of fallback function for other functions.
  • JSON AST: Remove storage qualifier for type name strings.
  • Parser: Fix internal compiler error when parsing var declaration without identifier.
  • Parser: Fix parsing of getters for function type variables.
  • Standard JSON: Support constantinople as evmVersion properly.
  • Static Analyzer: Fix non-deterministic order of unused variable warnings.
  • Static Analyzer: Invalid arithmetic with constant expressions causes errors.
  • Type Checker: Fix detection of recursive structs.
  • Type Checker: Fix asymmetry bug when comparing with literal numbers.
  • Type System: Improve error message when attempting to shift by a fractional amount.
  • Type System: Make external library functions accessible.
  • Type System: Prevent encoding of weird types.
  • Type System: Restrict rational numbers to 4096 bits.

We especially thank all our open source community contributors:

Sergiusz Bazanski, Federico Bond, Anthony Broad-Crawford, Jason Cobb, dongsamb, Robbie Ferguson, Kevin Florenzano, Grzegorz Hasse, hydai, Lefteris Karapetsas, kevinflo, NetX, Daniel R, Matías A. Ré Medina, Roman, Yosyp Schwab, wbt, Li Xuanji, Haoliang Yu

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