This CL enables the primary constructors feature by default in Dart 3.13.
The primary constructors feature is a brevity feature. There are no new semantics, but it allows us to express declarations in a less verbose way.
This feature allows one constructor and a set of instance variables to be specified in the header of a declaration.
Currently a declaration with a constructor and some fields is written as:
```dart
// Current syntax.
class Point {
int x;
int y;
Point(this.x, this.y);
}
```
With a primary constructor, we would write the above as:
```
class Point(var int x, var int y);
```
If a primary constructor needs an initializer list or a body, they can be
specified inside the class using the `this` body syntax:
```dart
class Point(var int x, var int y) {
this : assert(x >= 0) {
print('Point created at $x, $y');
}
}
```
As part of this feature, you can also use the `new` and `factory` keywords to
declare constructors in the class body without repeating the class name:
```dart
class Point {
int x, y;
// Equivalent to Point(this.x, this.y)
new(this.x, this.y);
// Equivalent to Point.origin()
new origin() : x = 0, y = 0;
// Equivalent to factory Point.clone(Point other)
factory clone(Point other) => Point(other.x, other.y);
}
```
To learn more about the feature, check out the feature specification located here: https://github.com/dart-lang/language/blob/main/accepted/future-releases/primary-constructors/feature-specification.md
Tested: Has existing language, CFE, analyzer, analysis server tests.
Bug: https://github.com/dart-lang/sdk/issues/61524
Change-Id: I296f2fcd918b87bf2a1dd00256340759866c2423
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/489241
Reviewed-by: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Michael Thomsen <mit@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
Make it available on the stable branch.
Fix the version numbers for when it was enabled. (3.9 as experiment
enabled is not entirely correct, as the experiment was not available
on the stable channel in 3.9, only on betas of 3.9.)
And disable passing data assets under the same experiment flag.
Note: It seems that it was accidentally still marked as 3.9 and then
got swept up in https://dart-review.googlesource.com/c/sdk/+/443803.
TEST=dartdev native assets tests
Bug: https://github.com/dart-lang/sdk/issues/50565
Change-Id: I4c44ad22e32673d6a951017d0cf6d3374dd20429
Cq-Include-Trybots: luci.dart.try:pkg-linux-debug-try,pkg-linux-release-arm64-try,pkg-linux-release-try,pkg-mac-release-arm64-try,pkg-mac-release-try,pkg-win-release-arm64-try,pkg-win-release-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449803
Reviewed-by: Ivan Inozemtsev <iinozemtsev@google.com>
Reviewed-by: Michael Goderbauer <goderbauer@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
In discussion with the language team, we've decided to ship this
feature in Dart 3.4. This CL contains a minimal CHANGELOG entry for
the feature; I plan to expand on it once I'm finished with the feature
specification document.
Change-Id: Iac86ebed322feb8e478bf5a6780d50adb433ed7f
Tested: trybots
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/355900
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
This language feature allows the user to declare a static type using
`extension type` syntax, for example:
extension type IdNumber(int i) {
operator <(IdNumber other) => i < other.i;
bool isValid(Some parameters) => ...;
}
This behaves similarly to a "wrapper" class:
class IdNumber {
final int i;
IdNumber(this.i);
operator <(IdNumber other) => i < other.i;
bool isValid(Some parameters) => ...;
}
However, at runtime, no wrapper objects are created; instead, an
instance of the extension type is represented directly by its
"representation type" (`int` in the above example), and methods like
`isValid` are resolved statically. This gives developers an
abstraction mechanism with the advantage of zero runtime performance
cost, since no extra heap space is required, and no extra instructions
are needed to convert between an extension type and its underlying
representation.
The disadvantage of using extension types as an abstraction mechanism
is that since no wrapper objects are created at runtime, the
abstraction can be bypassed using `dynamic`, runtime casts, or by
"laundering" the object through contravariant generic methods like
`List.add` (which are runtime checked in Dart). For example:
main() {
var id = IdNumber(1);
var list1 = <int>[];
List<Object> list2 = list1;
list2.add(id); // OK at compile time because `IdNumber` is a
// subtype of `Object`. OK at runtime because
// at runtime, `IdNumber` and `int` are
// indistinguishable.
int i = list1[0];
print(i);
}
Extension types are expected to be particularly useful for
low-overhead decoding of external data formats (such as JSON), and for
inter-operation with other languages (such as Javascript).
For additional information see the feature specification:
https://github.com/dart-lang/language/blob/main/accepted/future-releases/extension-types/feature-specification.md
Change-Id: I900a3a25dcfc38bfa9c9f9b5b9fa20f362883653
Tested: Standard trybots
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/335062
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Leaf Petersen <leafp@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
Please prefer not to revert this change. Any tests that fail are release
blockers and need to be approved and urgently fixed forward. Dart 3.2
has already been cut and the version number must be updated. It is
acceptable for rolls to be blocked until the release blockers have been
resolved as P0 issues.
Remove needless version number comment from experimental_features to
remove duplicated information and simplify version updates.
Update dartdoc to a version that supports 3.3.
Change-Id: I1a19aa86e185c99e61374665f18cf24c498935a5
Tested: CQ
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/329588
Commit-Queue: Slava Egorov <vegorov@google.com>
Auto-Submit: Jonas Termansen <sortie@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Remove needless version number comment from experimental_features to
remove duplicated information and simplify version updates.
Tested: CQ
Change-Id: I864bfc44070136406e95fdaf4d83f491b2c95943
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/329460
Reviewed-by: Alexander Thomas <athom@google.com>
This language feature allows type promotion to apply to private final
fields, e.g.:
class C {
final int? _x;
C(this._x);
}
f(C c) {
if (c._x != null) {
print(c._x.abs()); // (1)
}
}
Previously the line marked (1) would have needed to be written
`print(c._x!.abs());`.
Note that to ensure soundness, there are certain restrictions:
- Public fields don't undergo promotion (because a public field might
be overridden by a class in some other library).
- Non-final fields don't undergo promotion (because a non-final field
might be modified as a side effect of code executed between the type
test and the field's usage).
- Fields that are forwarded to `noSuchMethod` in the same library
don't undergo promotion (because there's no guarantee that
`noSuchMethod` will return the same value on every invocation). For
example:
class C {
final int? _x;
C(this._x);
}
class D implements C {
@override
noSuchMethod(...) => ...;
}
f(C c) {
if (c._x != null) {
print(c._x.abs()); // ERROR: `c._x` might dispatch to
// `D.noSuchMethod`, in which case there's
// no guarantee that it will return a
// non-null value the second time it's
// invoked.
}
}
- If two classes define fields or getters of the same name, and
promotion is not permitted for one of them, then it isn't permitted
for the other. This is because there might be a class in some other
library that's a subclass of both classes, causing a reference to
one field or getter to dispatch to the other. For example:
class C {
final int? _x;
C(this._x);
}
class D {
int? get _x => ...;
}
f(C c) {
if (c._x != null) {
print(c._x.abs()); // ERROR: `c._x` might dispatch to `D._x`
// (e.g. because some library might declare
// `class E extends D implements C`), in
// which case there's no guarantee that it
// will return a non-null value the second
// time it's invoked.
}
}
Change-Id: Ib9183581aa0194377e38ab70d37c3e9f0bb57a75
Bug: https://github.com/dart-lang/language/issues/2020
Tested: TAP global presubmit
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/314600
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
This turns on the flags for these two language features and makes
them generally accessible.
Doing so causes a number of tests to fail, but the failures are
approved and there are filed issues for them. Most of the
failures are minor or only affect code using the new language
features.
This CL:
- Enables the features in experimental_features.yaml.
- Re-generates all of the various files generated from that.
- Makes some analyzer and front end changes that this CL
inherited from Paul's original CL flipping all of the 3.0
feature flags. I don't know what these changes are about, but
I assume they are necessary.
- Pins a couple of tests to 2.19 since they deliberately test
behavior that is specific to 2.19. (For most test changes, I've
landed them separately, but there are a couple of stragglers
in this CL.)
This doesn't enable "class-modifiers" or "sealed-types" and doesn't
include the core lib changes related to those.
TEST=On bots
Change-Id: Id387753772286a958e20a3589a6e983995f2e4a6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/286344
Auto-Submit: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Jake Macdonald <jakemac@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Includes several updates to tests that needed to land with this flip, as well as some other tests that needed to be updated and could land separately, but are being included here to expedite things.
Removes some unnecessary experimental release versions, as well as bringing up to date the generated files, which were previously out of sync with the yaml file.
TEST=bots
Change-Id: I71a86d7a86190069b504bd27d687f62b97a7251e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/285080
Commit-Queue: Jake Macdonald <jakemac@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Kallen Tu