Enable the extension types language feature.
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>
diff --git a/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart b/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart
index 80d3cac..e3b3ad0 100644
--- a/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/experiments/flags.dart
@@ -82,9 +82,9 @@
inlineClass(
name: 'inline-class',
- isEnabledByDefault: false,
+ isEnabledByDefault: true,
isExpired: false,
- experimentEnabledVersion: defaultLanguageVersion,
+ experimentEnabledVersion: const Version(3, 3),
experimentReleasedVersion: const Version(3, 3)),
macros(
diff --git a/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart b/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart
index 3d8960d..d5252cd 100644
--- a/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/experiments.g.dart
@@ -244,8 +244,8 @@
isEnabledByDefault: IsEnabledByDefault.inline_class,
isExpired: IsExpired.inline_class,
documentation: 'Extension Types',
- experimentalReleaseVersion: Version.parse('3.3.0'),
- releaseVersion: null,
+ experimentalReleaseVersion: null,
+ releaseVersion: Version.parse('3.3.0'),
);
static final macros = ExperimentalFeature(
@@ -444,7 +444,7 @@
static const bool inference_update_2 = true;
/// Default state of the experiment "inline-class"
- static const bool inline_class = false;
+ static const bool inline_class = true;
/// Default state of the experiment "macros"
static const bool macros = false;
diff --git a/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart b/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart
index c3ddf07..4566eea 100644
--- a/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart
+++ b/pkg/front_end/lib/src/api_prototype/experimental_flags_generated.dart
@@ -141,10 +141,10 @@
static const ExperimentalFlag inlineClass = const ExperimentalFlag(
name: 'inline-class',
- isEnabledByDefault: false,
+ isEnabledByDefault: true,
isExpired: false,
- enabledVersion: defaultLanguageVersion,
- experimentEnabledVersion: defaultLanguageVersion,
+ enabledVersion: const Version(3, 3),
+ experimentEnabledVersion: const Version(3, 3),
experimentReleasedVersion: const Version(3, 3));
static const ExperimentalFlag macros = const ExperimentalFlag(
diff --git a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.expect b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.expect
index 5effcec..715535b 100644
--- a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.expect
+++ b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.expect
@@ -3,7 +3,7 @@
// Problems in library:
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:7:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType1(int it) {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
@@ -11,7 +11,7 @@
// ^^^^^^^^^^^^^
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:8:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType2<T>._(int it) implements int, ExtensionType1 {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
diff --git a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.transformed.expect b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.transformed.expect
index 5effcec..715535b 100644
--- a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.strong.transformed.expect
@@ -3,7 +3,7 @@
// Problems in library:
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:7:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType1(int it) {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
@@ -11,7 +11,7 @@
// ^^^^^^^^^^^^^
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:8:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType2<T>._(int it) implements int, ExtensionType1 {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
diff --git a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.expect b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.expect
index 5effcec..715535b 100644
--- a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.expect
+++ b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.expect
@@ -3,7 +3,7 @@
// Problems in library:
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:7:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType1(int it) {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
@@ -11,7 +11,7 @@
// ^^^^^^^^^^^^^
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:8:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType2<T>._(int it) implements int, ExtensionType1 {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
diff --git a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.modular.expect b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.modular.expect
index 5effcec..715535b 100644
--- a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.modular.expect
+++ b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.modular.expect
@@ -3,7 +3,7 @@
// Problems in library:
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:7:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType1(int it) {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
@@ -11,7 +11,7 @@
// ^^^^^^^^^^^^^
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:8:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType2<T>._(int it) implements int, ExtensionType1 {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
diff --git a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.outline.expect b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.outline.expect
index 49eaf15..9107d2f 100644
--- a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.outline.expect
+++ b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.outline.expect
@@ -3,7 +3,7 @@
// Problems in library:
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:7:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType1(int it) {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
@@ -11,7 +11,7 @@
// ^^^^^^^^^^^^^
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:8:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType2<T>._(int it) implements int, ExtensionType1 {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
diff --git a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.transformed.expect b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.transformed.expect
index 5effcec..715535b 100644
--- a/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/general/extension_type_declaration_disabled.dart.weak.transformed.expect
@@ -3,7 +3,7 @@
// Problems in library:
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:7:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType1(int it) {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
@@ -11,7 +11,7 @@
// ^^^^^^^^^^^^^
//
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:8:11: Error: The 'inline-class' language feature is disabled for this library.
-// Try removing the `@dart=` annotation or setting the language version to the current release or higher.
+// Try removing the `@dart=` annotation or setting the language version to 3.3 or higher.
// extension type ExtensionType2<T>._(int it) implements int, ExtensionType1 {}
// ^^^^
// pkg/front_end/testcases/general/extension_type_declaration_disabled.dart:5:1: Context: This is the annotation that opts out this library from the 'inline-class' language feature.
diff --git a/pkg/linter/test/rule_test_support.dart b/pkg/linter/test/rule_test_support.dart
index 46347a8..93e4acdb 100644
--- a/pkg/linter/test/rule_test_support.dart
+++ b/pkg/linter/test/rule_test_support.dart
@@ -174,7 +174,7 @@
bool get dumpAstOnFailures => true;
- List<String> get experiments => ['inline-class', 'macros'];
+ List<String> get experiments => ['macros'];
/// The path that is not in [workspaceRootPath], contains external packages.
String get packagesRootPath => '/packages';
diff --git a/pkg/linter/test/rules/annotate_overrides_test.dart b/pkg/linter/test/rules/annotate_overrides_test.dart
index 895b7e2..d7d5296 100644
--- a/pkg/linter/test/rules/annotate_overrides_test.dart
+++ b/pkg/linter/test/rules/annotate_overrides_test.dart
@@ -15,8 +15,6 @@
@reflectiveTest
class AnnotateOverridesTest extends LintRuleTest {
@override
- List<String> get experiments => ['inline-class'];
- @override
String get lintRule => 'annotate_overrides';
test_class_fieldWithAnnotation() async {
diff --git a/pkg/linter/test/rules/avoid_setters_without_getters_test.dart b/pkg/linter/test/rules/avoid_setters_without_getters_test.dart
index 6db3869..b5eac0c 100644
--- a/pkg/linter/test/rules/avoid_setters_without_getters_test.dart
+++ b/pkg/linter/test/rules/avoid_setters_without_getters_test.dart
@@ -15,9 +15,6 @@
@reflectiveTest
class AvoidSettersWithoutGettersTest extends LintRuleTest {
@override
- List<String> get experiments => ['inline-class'];
-
- @override
String get lintRule => 'avoid_setters_without_getters';
test_enum() async {
diff --git a/pkg/linter/test/rules/unnecessary_getters_setters_test.dart b/pkg/linter/test/rules/unnecessary_getters_setters_test.dart
index 00823ba..3a25e4e 100644
--- a/pkg/linter/test/rules/unnecessary_getters_setters_test.dart
+++ b/pkg/linter/test/rules/unnecessary_getters_setters_test.dart
@@ -15,9 +15,6 @@
@reflectiveTest
class UnnecessaryGettersSettersTest extends LintRuleTest {
@override
- List<String> get experiments => ['inline-class'];
-
- @override
String get lintRule => 'unnecessary_getters_setters';
test_necessary_differentType() async {
diff --git a/runtime/vm/experimental_features.cc b/runtime/vm/experimental_features.cc
index ba679c8..ff67a54 100644
--- a/runtime/vm/experimental_features.cc
+++ b/runtime/vm/experimental_features.cc
@@ -16,7 +16,7 @@
bool GetExperimentalFeatureDefault(ExperimentalFeature feature) {
constexpr bool kFeatureValues[] = {
- true, true, true, true, true, true, true, true, true, true,
+ true, true, true, true, true, true, true, true, true, true, true,
true, true, true, true, true, true, true, true, true, true,
};
ASSERT(static_cast<size_t>(feature) < ARRAY_SIZE(kFeatureValues));
@@ -25,6 +25,7 @@
const char* GetExperimentalFeatureName(ExperimentalFeature feature) {
constexpr const char* kFeatureNames[] = {
+ "inline-class",
"inference-update-2",
"sealed-class",
"class-modifiers",
diff --git a/runtime/vm/experimental_features.h b/runtime/vm/experimental_features.h
index ff5a37b..7e85347 100644
--- a/runtime/vm/experimental_features.h
+++ b/runtime/vm/experimental_features.h
@@ -12,6 +12,7 @@
namespace dart {
enum class ExperimentalFeature {
+ inline_class,
inference_update_2,
sealed_class,
class_modifiers,
diff --git a/tools/experimental_features.yaml b/tools/experimental_features.yaml
index 946b4e2..c9da51b 100644
--- a/tools/experimental_features.yaml
+++ b/tools/experimental_features.yaml
@@ -122,10 +122,6 @@
experimentalReleaseVersion: '3.3.0'
help: "Static meta-programming"
- inline-class:
- experimentalReleaseVersion: '3.3.0'
- help: "Extension Types"
-
native-assets:
help: "Compile and bundle native assets."
@@ -145,6 +141,17 @@
# Shipped flags should be marked retired the following stable release.
#
+ inline-class:
+ enabledIn: '3.3.0'
+ validation: |
+ extension type E(String rep) {
+ String f() => '$rep enabled';
+ }
+ main() {
+ print(('feature' as E).f());
+ }
+ help: "Extension Types"
+
inference-update-2:
enabledIn: '3.2.0'
validation: |
