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Solidity 0.4.17 Release Announcement

Posted by Solidity Team on September 21, 2017


As we are getting closer to the next breaking release, we want to give everyone a heads up by introducing pragma experimental "v0.5.0" which already enables some of the new safety features of the 0.5.0 release.

Furthermore, this release finally checks the modifiers view (used to be named constant) and pure on functions. As a rule of thumb, use view if your function does not modify storage and pure if it does not even read any state information - but the compiler will also suggest the tightest restriction itself.

We also worked further on the new ABI encoder: Functions can now return structs. Switch it on using pragma experimental ABIEncoderV2. It should already work, but still generates more expensive code.

Finally, many new warnings were introduced and error messages improved.


  • Assembly Parser: Support multiple assignment (x, y := f()).
  • Code Generator: Keep a single copy of encoding functions when using the experimental "ABIEncoderV2".
  • Code Generator: Partial support for passing structs as arguments and return parameters (requires pragma experimental ABIEncoderV2; for now).
  • General: Support pragma experimental "v0.5.0"; to activate upcoming breaking changes.
  • General: Added .selector member on external function types to retrieve their signature.
  • Optimizer: Add new optimization step to remove unused JUMPDESTs.
  • Static Analyzer: Warn when using deprecated builtins sha3 and suicide (replaced by keccak256 and selfdestruct, introduced in 0.4.2 and 0.2.0, respectively).
  • Syntax Checker: Warn if no visibility is specified on contract functions.
  • Type Checker: Display helpful warning for unused function arguments/return parameters.
  • Type Checker: Do not show the same error multiple times for events.
  • Type Checker: Greatly reduce the number of duplicate errors shown for duplicate constructors and functions.
  • Type Checker: Warn on using literals as tight packing parameters in keccak256, sha3, sha256 and ripemd160.
  • Type Checker: Enforce view and pure.
  • Type Checker: Enforce view / constant with error as experimental 0.5.0 feature.
  • Type Checker: Enforce fallback functions to be external as experimental 0.5.0 feature.


  • ABI JSON: Include all overloaded events.
  • Parser: Crash fix related to parseTypeName.
  • Type Checker: Allow constant byte arrays.

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

Download the new version of Solidity here.

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