### 0.4.0 (unreleased)
This release deliberately breaks backwards compatibility mostly to
enforce some safety features. The most important change is
...
Breaking Changes:
* Source files have to specify the compiler version they are
compatible with using e.g. `pragma solidity ^0.4.0;` or
`pragma solidity >=0.4.0 <0.4.8;`
* Contracts that want to receive Ether have to implement a fallback
function (contracts now throw if no fallback function is defined
and no function matches the signature).
* Failing contract creation through "new" throws now.
* Throw on division / modulus by zero
* Function call throws if target contract does not have code
* Modifiers are required to contain ``_`` (use ``if (false) _`` as a workaround if needed).
* Modifiers: return does not skip part in modifier after ``_``
* ``ecrecover`` now returns zero if the input is malformed (it previously returned garbage)
* Removed ``--interface`` (Solidity interface) output option
* JSON AST: General cleanup, renamed many nodes to match their C++ names.
* Json Output: srcmap-runtime renamed to srcmapRuntime
* Moved (and reworked) standard library contracts from inside the compiler to github.com/ethereum/solidity/std
(``import "std";`` or ``import owned;`` do not work anymore).
* Confusing and undocumented keyword "after" was removed.
* New reserved words: hex, payable, abstract, static, interface
Features:
* Hexadecimal string literals: ``hex"ab1248fe"``
* Internal: Inline assembly usable by the code generator.
* Commandline interface: Using ``-`` as filename allows reading from stdin.
* Interface Json: Fallback function is now part of the ABI.
* Interface: Version string now semver compatible.
Bugfixes:
* JSON AST: nodes were added at wrong parent
* Why3 translator: crash fix for exponentiation
* Type Checker: Fallback function cannot return data anymore.
Lots of changes to the documentation mainly by voluntary external contributors.
### 0.3.6 (2016-08-10)
Features:
* Formal verification: Take external effects on a contract into account.
* Type Checker: Warning about unused return value of low-level calls and send.
* Output: Source location and node id as part of AST output
* Output: Source location mappings for bytecode
* Output: Formal verification as part of json compiler output.
Bugfixes:
* Commandline Interface: Do not crash if input is taken from stdin.
* Scanner: Correctly support unicode escape codes in strings.
* JSON output: Fix error about relative / absolute source file names.
* JSON output: Fix error about invalid utf8 strings.
* Code Generator: Dynamic allocation of empty array caused infinite loop.
* Code Generator: Correctly calculate gas requirements for memcpy precompile.
* Optimizer: Clear known state if two code paths are joined.
### 0.3.5 (2016-06-10)
Features:
* Context-dependent path remappings (different modules can use the same library in different versions)
Bugfixes:
* Type Checking: Dynamic return types were removed when fetching data from external calls, now they are replaced by an "unusable" type.
* Type Checking: Overrides by constructors were considered making a function non-abstract.
### 0.3.4 (2016-05-31)
No change outside documentation.
### 0.3.3 (2016-05-27)
* Allow internal library functions to be called (by "inlining")
* Fractional/rational constants (only usable with fixed point types, which are still in progress)
* Inline assembly has access to internal functions (as jump labels)
* Running `solc` without arguments on a terminal will print help.
* Bugfix: Remove some non-determinism in code generation.
* Bugfix: Corrected usage of not / bnot / iszero in inline assembly
* Bugfix: Correctly clean bytesNN types before comparison
### 0.3.2 (2016-04-18)
* Bugfix: Inline assembly parser: `byte` opcode was unusable
* Bugfix: Error reporting: tokens for variably-sized types were not converted to string properly
* Bugfix: Dynamic arrays of structs were not deleted correctly.
* Bugfix: Static arrays in constructor parameter list were not decoded correctly.
### 0.3.1 (2016-03-31)
* Inline assembly
* Bugfix: Code generation: array access with narrow types did not clean higher order bits
* Bugfix: Error reporting: error reporting with unknown source location caused a crash
### 0.3.0 (2016-03-11)
BREAKING CHANGES:
* Added new keywords `assembly`, `foreign`, `fixed`, `ufixed`, `fixedNxM`, `ufixedNxM` (for various values of M and N), `timestamp`
* Number constant division does not round to integer, but to a fixed point type (e.g. `1 / 2 != 1`, but `1 / 2 == 0.5`).
* Library calls now default to use DELEGATECALL (e.g. called library functions see the same value as the calling function for `msg.value` and `msg.sender`).
* `<address>.delegatecall` as a low-level calling interface
Bugfixes:
* Fixed a bug in the optimizer that resulted in comparisons being wrong.
### 0.2.2 (2016-02-17)
* Index access for types `bytes1`, ..., `bytes32` (only read access for now).
* Bugfix: Type checker crash for wrong number of base constructor parameters.
### 0.2.1 (2016-01-30)
* Inline arrays, i.e. `var y = [1,x,f()];` if there is a common type for `1`, `x` and `f()`. Note that the result is always a fixed-length memory array and conversion to dynamic-length memory arrays is not yet possible.
* Import similar to ECMAScript6 import (`import "abc.sol" as d` and `import {x, y} from "abc.sol"`).
* Commandline compiler solc automatically resolves missing imports and allows for "include directories".
* Conditional: `x ? y : z`
* Bugfix: Fixed several bugs where the optimizer generated invalid code.
* Bugfix: Enums and structs were not accessible to other contracts.
* Bugfix: Fixed segfault connected to function paramater types, appeared during gas estimation.
* Bugfix: Type checker crash for wrong number of base constructor parameters.
* Bugfix: Allow function overloads with different array types.
* Bugfix: Allow assignments of type `(x) = 7`.
* Bugfix: Type `uint176` was not available.
* Bugfix: Fixed crash during type checking concerning constructor calls.
* Bugfix: Fixed crash during code generation concerning invalid accessors for struct types.
* Bugfix: Fixed crash during code generating concerning computing a hash of a struct type.
### 0.2.0 (2015-12-02)
* **Breaking Change**: `new ContractName.value(10)()` has to be written as `(new ContractName).value(10)()`
* Added `selfdestruct` as an alias for `suicide`.
* Allocation of memory arrays using `new`.
* Binding library functions to types via `using x for y`
* `addmod` and `mulmod` (modular addition and modular multiplication with arbitrary intermediate precision)
* Bugfix: Constructor arguments of fixed array type were not read correctly.
* Bugfix: Memory allocation of structs containing arrays or strings.
* Bugfix: Data location for explicit memory parameters in libraries was set to storage.
### 0.1.7 (2015-11-17)
* Improved error messages for unexpected tokens.
* Proof-of-concept transcompilation to why3 for formal verification of contracts.
* Bugfix: Arrays (also strings) as indexed parameters of events.
* Bugfix: Writing to elements of `bytes` or `string` overwrite others.
* Bugfix: "Successor block not found" on Windows.
* Bugfix: Using string literals in tuples.
* Bugfix: Cope with invalid commit hash in version for libraries.
* Bugfix: Some test framework fixes on windows.
### 0.1.6 (2015-10-16)
* `.push()` for dynamic storage arrays.
* Tuple expressions (`(1,2,3)` or `return (1,2,3);`)
* Declaration and assignment of multiple variables (`var (x,y,) = (1,2,3,4,5);` or `var (x,y) = f();`)
* Destructuring assignment (`(x,y,) = (1,2,3)`)
* Bugfix: Internal error about usage of library function with invalid types.
* Bugfix: Correctly parse `Library.structType a` at statement level.
* Bugfix: Correctly report source locations of parenthesized expressions (as part of "tuple" story).
### 0.1.5 (2015-10-07)
* Breaking change in storage encoding: Encode short byte arrays and strings together with their length in storage.
* Report warnings
* Allow storage reference types for public library functions.
* Access to types declared in other contracts and libraries via `.`.
* Version stamp at beginning of runtime bytecode of libraries.
* Bugfix: Problem with initialized string state variables and dynamic data in constructor.
* Bugfix: Resolve dependencies concerning `new` automatically.
* Bugfix: Allow four indexed arguments for anonymous events.
* Bugfix: Detect too large integer constants in functions that accept arbitrary parameters.
### 0.1.4 (2015-09-30)
* Bugfix: Returning fixed-size arrays.
* Bugfix: combined-json output of solc.
* Bugfix: Accessing fixed-size array return values.
* Bugfix: Disallow assignment from literal strings to storage pointers.
* Refactoring: Move type checking into its own module.
### 0.1.3 (2015-09-25)
* `throw` statement.
* Libraries that contain functions which are called via CALLCODE.
* Linker stage for compiler to insert other contract's addresses (used for libraries).
* Compiler option to output runtime part of contracts.
* Compile-time out of bounds check for access to fixed-size arrays by integer constants.
* Version string includes libevmasm/libethereum's version (contains the optimizer).
* Bugfix: Accessors for constant public state variables.
* Bugfix: Propagate exceptions in clone contracts.
* Bugfix: Empty single-line comments are now treated properly.
* Bugfix: Properly check the number of indexed arguments for events.
* Bugfix: Strings in struct constructors.
### 0.1.2 (2015-08-20)
* Improved commandline interface.
* Explicit conversion between `bytes` and `string`.
* Bugfix: Value transfer used in clone contracts.
* Bugfix: Problem with strings as mapping keys.
* Bugfix: Prevent usage of some operators.
### 0.1.1 (2015-08-04)
* Strings can be used as mapping keys.
* Clone contracts.
* Mapping members are skipped for structs in memory.
* Use only a single stack slot for storage references.
* Improved error message for wrong argument count. (#2456)
* Bugfix: Fix comparison between `bytesXX` types. (#2087)
* Bugfix: Do not allow floats for integer literals. (#2078)
* Bugfix: Some problem with many local variables. (#2478)
* Bugfix: Correctly initialise `string` and `bytes` state variables.
* Bugfix: Correctly compute gas requirements for callcode.
### 0.1.0 (2015-07-10)
