[cfe,dart2js] Reuse field reference for static late lowering

In response to https://github.com/flutter/flutter/issues/89740 and
https://github.com/flutter/flutter/issues/94561

Change-Id: I22c100a575b91e70a2c5835b8db6dd450f319ce7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/221947
Reviewed-by: Mayank Patke <fishythefish@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

pkg/compiler/lib/src/kernel/transformations/late_lowering.dart

@@ -280,13 +280,17 @@ class LateLowering {
       Name name = field.name;
       Uri fileUri = field.fileUri;
       DartType type = field.type;
+      // We need to unbind the canonical name since we reuse the reference but
+      // change the name.
+      field.fieldReference.canonicalName?.unbind();
       Field fieldCell = Field.immutable(_mangleFieldCellName(field),
           type: InterfaceType(_coreTypes.cellClass, nonNullable),
           initializer: _callCellConstructor(
               _nameLiteral(name.text, fileOffset), fileOffset),
           isFinal: true,
           isStatic: true,
-          fileUri: fileUri)
+          fileUri: fileUri,
+          fieldReference: field.fieldReference)
         ..fileOffset = fileOffset
         ..isNonNullableByDefault = true;
       StaticGet fieldCellAccess() =>
@@ -364,6 +368,8 @@ class LateLowering {
     Expression? initializer = field.initializer;
     Class enclosingClass = field.enclosingClass!;
 
+    // We need to unbind the canonical name since we reuse the reference but
+    // change the name.
     field.fieldReference.canonicalName?.unbind();
     Field backingField = Field.mutable(mangledName,
         type: type,

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart

@@ -0,0 +1,12 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'main_lib.dart';
+
+main() {
+  MyInt.a = 42;
+  print(MyInt.a);
+  MyInt.b = 87;
+  print(MyInt.b);
+}

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.strong.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+//   MyInt.a = 42;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  invalid-expression "pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+  MyInt.a = 42;
+        ^";
+  core::print(mai::_#MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = mai::_#MyInt|a;
+  static field b = mai::MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+late static field core::int MyInt|b = 42;
+static get MyInt|a() → core::int
+  return mai::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return mai::_#MyInt|a.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.strong.transformed.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+//   MyInt.a = 42;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  invalid-expression "pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+  MyInt.a = 42;
+        ^";
+  core::print(mai::_#MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = mai::_#MyInt|a;
+  static field b = mai::MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+late static field core::int MyInt|b = 42;
+static get MyInt|a() → core::int
+  return mai::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return mai::_#MyInt|a.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.textual_outline.expect

@@ -0,0 +1,3 @@
+import 'main_lib.dart';
+
+main() {}

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.textual_outline_modelled.expect

@@ -0,0 +1,3 @@
+import 'main_lib.dart';
+
+main() {}

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.weak.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+//   MyInt.a = 42;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  invalid-expression "pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+  MyInt.a = 42;
+        ^";
+  core::print(mai::_#MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = mai::_#MyInt|a;
+  static field b = mai::MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+late static field core::int MyInt|b = 42;
+static get MyInt|a() → core::int
+  return mai::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return mai::_#MyInt|a.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.weak.outline.expect

@@ -0,0 +1,27 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic
+  ;
+
+library /*isNonNullableByDefault*/;
+import self as self2;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = self2::_#MyInt|a;
+  static field b = self2::_#MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+static final field _la::_Cell _#MyInt|b = new _la::_Cell::named("MyInt|b");
+static get MyInt|a() → core::int
+  return self2::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return self2::_#MyInt|a.{_la::_Cell::value} = value;
+static get MyInt|b() → core::int
+  return self2::_#MyInt|b.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|b(core::int value) → void
+  return self2::_#MyInt|b.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart.weak.transformed.expect

@@ -0,0 +1,38 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+//   MyInt.a = 42;
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  invalid-expression "pkg/front_end/testcases/dart2js/flutter_issue94561/main.dart:8:9: Error: Setter not found: 'a'.
+  MyInt.a = 42;
+        ^";
+  core::print(mai::_#MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = mai::_#MyInt|a;
+  static field b = mai::MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+late static field core::int MyInt|b = 42;
+static get MyInt|a() → core::int
+  return mai::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return mai::_#MyInt|a.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart

@@ -0,0 +1,12 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'main_lib.dart';
+
+main() {
+  MyInt.a = 42;
+  print(MyInt.a);
+  MyInt.b = 87;
+  print(MyInt.b);
+}

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.strong.expect

@@ -0,0 +1,24 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  mai::MyInt|a = 42;
+  core::print(mai::MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+extension MyInt on core::int {
+  static field a = mai::MyInt|a;
+  static field b = mai::MyInt|b;
+}
+late static field core::int MyInt|a;
+late static field core::int MyInt|b = 42;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.strong.transformed.expect

@@ -0,0 +1,29 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  mai::MyInt|a = 42;
+  core::print(mai::MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = mai::_#MyInt|a;
+  static field b = mai::MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+late static field core::int MyInt|b = 42;
+static get MyInt|a() → core::int
+  return mai::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return mai::_#MyInt|a.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.textual_outline.expect

@@ -0,0 +1,3 @@
+import 'main_lib.dart';
+
+main() {}

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.textual_outline_modelled.expect

@@ -0,0 +1,3 @@
+import 'main_lib.dart';
+
+main() {}

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.weak.expect

@@ -0,0 +1,24 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  mai::MyInt|a = 42;
+  core::print(mai::MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+extension MyInt on core::int {
+  static field a = mai::MyInt|a;
+  static field b = mai::MyInt|b;
+}
+late static field core::int MyInt|a;
+late static field core::int MyInt|b = 42;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.weak.outline.expect

@@ -0,0 +1,18 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic
+  ;
+
+library /*isNonNullableByDefault*/;
+import self as self2;
+import "dart:core" as core;
+
+extension MyInt on core::int {
+  static field a = self2::MyInt|a;
+  static field b = self2::MyInt|b;
+}
+late static field core::int MyInt|a;
+late static field core::int MyInt|b;

pkg/front_end/testcases/dart2js/flutter_issue94561/main.no_link.dart.weak.transformed.expect

@@ -0,0 +1,29 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+static method main() → dynamic {
+  mai::MyInt|a = 42;
+  core::print(mai::MyInt|a);
+  mai::MyInt|b = 87;
+  core::print(mai::MyInt|b);
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+import "dart:_late_helper" as _la;
+
+extension MyInt on core::int {
+  static field a = mai::_#MyInt|a;
+  static field b = mai::MyInt|b;
+}
+static final field _la::_Cell _#MyInt|a = new _la::_Cell::named("MyInt|a");
+late static field core::int MyInt|b = 42;
+static get MyInt|a() → core::int
+  return mai::_#MyInt|a.{_la::_Cell::readField}<core::int>(){() → core::int};
+static set MyInt|a(core::int value) → void
+  return mai::_#MyInt|a.{_la::_Cell::value} = value;

pkg/front_end/testcases/dart2js/flutter_issue94561/main_lib.dart

@@ -0,0 +1,8 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+extension MyInt on int {
+  static late int a;
+  static late int b = 42;
+}

pkg/front_end/testcases/dart2js/flutter_issue94561/test.options

@@ -0,0 +1 @@
+main_lib.dart

pkg/kernel/lib/binary/ast_to_binary.dart

@@ -2498,6 +2498,8 @@ class BinaryPrinter implements Visitor<void>, BinarySink {
       writeName(descriptor.name);
       writeByte(descriptor.kind.index);
       writeByte(descriptor.flags);
+      assert(descriptor.member.canonicalName != null,
+          "No canonical name for ${descriptor}.");
       writeNonNullCanonicalNameReference(descriptor.member.canonicalName!);
     }
   }