cerc-io/solidity
16
0
Fork 0
mirror of https://github.com/ethereum/solidity synced 2023-10-03 13:03:40 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Merge pull request #10114 from ethereum/restructureBreaking

Browse Source 
Re-structure list of breaking changes.
This commit is contained in:
Harikrishnan Mulackal 2020-10-26 18:49:38 +01:00 committed by GitHub
commit 71d815f565
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 25 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
docs/080-breaking-changes.rst
View File

@ -3,32 +3,42 @@ Solidity v0.8.0 Breaking Changes
******************************** ********************************
This section highlights the main breaking changes introduced in Solidity This section highlights the main breaking changes introduced in Solidity
version 0.8.0, along with the reasoning behind the changes and how to update version 0.8.0.
affected code.
For the full list check For the full list check
`the release changelog <https://github.com/ethereum/solidity/releases/tag/v0.8.0>`_. `the release changelog <https://github.com/ethereum/solidity/releases/tag/v0.8.0>`_.
Semantic and Syntactic Changes Silent Changes of the Semantics
============================== ===============================
This section lists changes where you have to modify your code This section lists changes where existing code changes its behaviour without
and it does something else afterwards. the compiler notifying you about it.
* Arithmetic operations revert on underflow and overflow. You can use ``unchecked { ... }`` to use
the previous wrapping behaviour.
Checks for overflow are very common, so we made them the default to increase readability of code,
even if it comes at a slight increase of gas costs.
* Explicit conversions from negative literals and literals larger than ``type(uint160).max`` to ``address`` are now disallowed.
* Exponentiation is right associative, i.e., the expression ``a**b**c`` is parsed as ``a**(b**c)``. * Exponentiation is right associative, i.e., the expression ``a**b**c`` is parsed as ``a**(b**c)``.
Before 0.8.0, it was parsed as ``(a**b)**c``. Before 0.8.0, it was parsed as ``(a**b)**c``.
Semantic only Changes This is the common way to parse the exponentiation operator.
=====================
* Failing assertions (and other internal checks like division by zero) do not use the invalid opcode anymore but instead revert * Failing assertions and other internal checks like division by zero or arithmetic overflow do
with error data equal to a function call to ``Panic(uint256)`` with an error code specific to the circumstances. not use the invalid opcode but instead the revert opcode.
More specifically, they will use error data equal to a function call to ``Panic(uint256)`` with an error code specific
to the circumstances.
This will save gas on errors while it still allows static analysis tools to detect these situations. This will save gas on errors while it still allows static analysis tools to distinguish
these situations from a revert on invalid input, like a failing ``require``.
New Restrictions
================
Syntactic Only Changes * Explicit conversions from negative literals and literals larger
====================== than ``type(uint160).max`` to ``address`` are disallowed.
The previous behaviour was likely ambiguous.
* The global functions ``log0``, ``log1``, ``log2``, ``log3`` and ``log4`` have been removed. * The global functions ``log0``, ``log1``, ``log2``, ``log3`` and ``log4`` have been removed.