This release is focused on stability and also introduces some new smart contract safety features: require, assert and transfer. Note that the new revert function will only be gas-efficient starting from homestead.


  • Add assert(condition), which throws if condition is false (meant for internal errors).
  • Add require(condition), which throws if condition is false (meant for invalid input).
  • Commandline interface: Do not overwrite files unless forced.
  • Introduce .transfer(value) for sending Ether.
  • Code generator: Support revert() to abort with rolling back, but not consuming all gas.
  • Inline assembly: Support revert (EIP140) as an opcode.
  • Parser: Support scientific notation in numbers (e.g. 2e8 and 200e-2).
  • Type system: Support explicit conversion of external function to address.
  • Type system: Warn if base of exponentiation is literal (result type might be unexpected).
  • Type system: Warn if constant state variables are not compile-time constants.


  • Commandline interface: Always escape filenames (replace /, : and . with _).
  • Commandline interface: Do not try creating paths . and ...
  • Commandline interface: Allow long library names.
  • Parser: Disallow octal literals.
  • Type system: Fix a crash caused by continuing on fatal errors in the code.
  • Type system: Disallow compound assignment for tuples.
  • Type system: Detect cyclic dependencies between constants.
  • Type system: Disallow arrays with negative length.
  • Type system: Fix a crash related to invalid binary operators.
  • Type system: Disallow var declaration with empty tuple type.
  • Type system: Correctly convert function argument types to pointers for member functions.
  • Type system: Move privateness of constructor into AST itself.
  • Inline assembly: Charge one stack slot for non-value types during analysis.
  • Assembly output: Print source location before the operation it refers to instead of after.
  • Optimizer: Stop trying to optimize tricky constants after a while.

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

Download the new version of Solidity here.