Crystal 1.6.0 is released!
We are delivering a new release with several bugfixes and improvements. Below we list the most important or interesting changes, without mentioning several bugfixes and smaller enhancements. For more details, visit the changelog. Breaking changes are marked with ⚠️.
Pre-built packages are available on GitHub Releases and our official distribution channels. See crystal-lang.org/install for installation instructions.
Stats
In this release we included 183 changes since the 1.5.1 release by 26 contributors. We thank all the effort put into improving the language! ❤️
Below we list the most remarkable changes in the language and stdlib.
⚠️ Improvements in overload ordering
Union types may now be considered before a wider variety of types when searching for a suitable overload. Consider the following code:
module Foo(T)
end
class Bar1
include Foo(Int32)
end
class Bar2
include Foo(Int32)
end
def foo(x : Foo(Int32))
'a'
end
def foo(x : Bar1 | Bar2)
true
end
foo(Bar1.new)
Before 1.6.0 it would print 'a', meaning the generic case was considered first. Now it correctly prints true. If this affects your code, here is a quick guide to better understand and fix it:
-
This happens whenever a parameter has a union type restriction in one overload, and the same parameter in another overload has a restriction that isn’t a path (the name of a type) or an underscore (
_). -
To preserve the old ordering, remove the union overload. Note that it was not being used.
-
To ensure the new ordering applies to older releases, move the union overload above the generic one. (This is because previous Crystal versions consider the two overloads unordered.)
Several other improvements where added to the overloading search algorithm, but only under a special flag -Dpreview_overload_order.
⚠️ Refactor in console methods
By making some console methods available in Windows, a significant refactor lead to deprecating three macro methods in FileDescriptor: cooked_from_tc_mode!, noecho_from_tc_mode!, and raw_from_tc_mode!. Additionally, methods #noecho! and #raw! now return nil.
⚠️ Refactors in File::Info
Another refactor lead to an improvement in the File API, which was breaking the abstraction by returning an object intended to be internal. In practice, if for some reason you ended up with an object of type Crystal::System::FileInfo, it should now be File::Info.
Improvements in the interpreter
In this release a number of interpreter bugs got fixed. We are still working towards incorporating it in the major platforms; in the meantime you can build the compiler with interpreter support locally with make interpreter=1, see the interpreter introduction post for more info.
Performance improvements
Many performance improvements in the compiler and the stdlib went into this release. We don’t have a benchmark for you, but users reported non-negligible improvements in compilation speed and memory consumption.
Improvements in the compiler for Windows
Several improvements landed in this release regarding Windows support, most notably experimental support for building the interpreter, and Mutex support.
Other improvements
Dir.pwdnow respects$PWD(ref).- Support for Unicode 15.0 (ref).
- Support for unicode normalization (ref). Relevant information can be found in the API docs.
We have been able to do all of this thanks to the continued support of 84codes, Nikola Motor Company and every other sponsor. To maintain and increase the development pace, donations and sponsorships are essential. OpenCollective is available for that.
Reach out to crystal@manas.tech if you’d like to become a direct sponsor or find other ways to support Crystal. We thank you in advance!
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