Fix #28120, strong mode allows field overrides

Fix #28119, DDC supports field overrides without @virtual
Fix #28801, devirtualize private fields in DDC where possible
Fix #28589, stop supporting @virtual in strong mode

[email protected], [email protected]

Review-Url: https://codereview.chromium.org/2781443003 .

Author: Jennifer Messerly

pkg/analyzer/lib/src/dart/element/element.dart

@@ -2520,12 +2520,6 @@ class ElementAnnotationImpl implements ElementAnnotation {
    */
   static String _REQUIRED_VARIABLE_NAME = "required";
 
-  /**
-   * The name of the top-level variable used to mark a member as intended to be
-   * overridden.
-   */
-  static String _VIRTUAL_VARIABLE_NAME = "virtual";
-
   /**
    * The element representing the field, variable, or constructor being used as
    * an annotation.
@@ -2634,18 +2628,6 @@ class ElementAnnotationImpl implements ElementAnnotation {
           element.name == _REQUIRED_VARIABLE_NAME &&
           element.library?.name == _META_LIB_NAME;
 
-  /**
-   * Return `true` if this annotation marks the associated member as supporting
-   * overrides.
-   *
-   * This is currently used by fields in Strong Mode, as other members are
-   * already virtual-by-default.
-   */
-  bool get isVirtual =>
-      element is PropertyAccessorElement &&
-      element.name == _VIRTUAL_VARIABLE_NAME &&
-      element.library?.name == _META_LIB_NAME;
-
   /**
    * Get the library containing this annotation.
    */
@@ -4273,14 +4255,7 @@ class FieldElementImpl extends PropertyInducingElementImpl
   }
 
   @override
-  bool get isVirtual {
-    for (ElementAnnotationImpl annotation in metadata) {
-      if (annotation.isVirtual) {
-        return true;
-      }
-    }
-    return false;
-  }
+  bool get isVirtual => true;
 
   @override
   ElementKind get kind => ElementKind.FIELD;

pkg/analyzer/test/generated/compile_time_error_code_test.dart

@@ -5291,10 +5291,8 @@ import 'lib1.dart';
 class C extends Object with A, B {}
 ''');
     await computeAnalysisResult(source);
-    assertErrors(source, [
-      CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION,
-      StrongModeCode.INVALID_FIELD_OVERRIDE
-    ]);
+    assertErrors(
+        source, [CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION]);
     verify([source]);
   }
 
@@ -5340,10 +5338,8 @@ import 'lib1.dart';
 class C extends A with B {}
 ''');
     await computeAnalysisResult(source);
-    assertErrors(source, [
-      CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION,
-      StrongModeCode.INVALID_FIELD_OVERRIDE
-    ]);
+    assertErrors(
+        source, [CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION]);
     verify([source]);
   }
 
@@ -5365,10 +5361,8 @@ import 'lib1.dart';
 class C extends A with A {}
 ''');
     await computeAnalysisResult(source);
-    assertErrors(source, [
-      CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION,
-      StrongModeCode.INVALID_FIELD_OVERRIDE
-    ]);
+    assertErrors(
+        source, [CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION]);
     verify([source]);
   }
 

pkg/analyzer/test/src/context/context_test.dart

@@ -4326,9 +4326,8 @@ class B extends A {
 }
 ''');
     _performPendingAnalysisTasks();
-    expect(context.getErrors(a).errors, hasLength(2));
+    expect(context.getErrors(a).errors, hasLength(1));
     // Update a.dart: rename "int foo" to "int bar".
-    // The strong mode "getter cannot override field" error is gone.
     context.setContents(
         a,
         r'''

pkg/analyzer/test/src/task/strong/checker_test.dart

@@ -726,10 +726,10 @@ class Base {
 }
 
 class Child extends Base {
-  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/A f1; // invalid for getter
-  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/C f2; // invalid for setter
-  /*error:INVALID_FIELD_OVERRIDE*/var f3;
-  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/dynamic f4;
+  /*error:INVALID_METHOD_OVERRIDE*/A f1; // invalid for getter
+  /*error:INVALID_METHOD_OVERRIDE*/C f2; // invalid for setter
+  var f3;
+  /*error:INVALID_METHOD_OVERRIDE*/dynamic f4;
 }
 
 class Child2 implements Base {
@@ -755,10 +755,10 @@ abstract class Base {
 }
 
 class Child extends Base {
-  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/A get f1 => null;
-  /*error:INVALID_FIELD_OVERRIDE*/C get f2 => null;
-  /*error:INVALID_FIELD_OVERRIDE*/get f3 => null;
-  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/dynamic get f4 => null;
+  /*error:INVALID_METHOD_OVERRIDE*/A get f1 => null;
+  C get f2 => null;
+  get f3 => null;
+  /*error:INVALID_METHOD_OVERRIDE*/dynamic get f4 => null;
 }
 
 class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_FOUR*/Child2 implements Base {
@@ -779,8 +779,8 @@ class F {
 }
 
 class G extends F {
-  /*error:INVALID_FIELD_OVERRIDE*/final ToVoid<int> f = null;
-  /*error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/final ToVoid<dynamic> g = null;
+  final ToVoid<int> f = null;
+  /*error:INVALID_METHOD_OVERRIDE*/final ToVoid<dynamic> g = null;
 }
 
 class H implements F {
@@ -815,7 +815,7 @@ class OverrideWithField extends C {
   set superX(int v) { super.x = v; }
 }
 class VirtualNotInherited extends OverrideWithField {
-  /*error:INVALID_FIELD_OVERRIDE*/int x;
+  int x;
 }
     ''');
   }
@@ -835,17 +835,17 @@ class Base {
 }
 
 class Child extends Base {
-  /*error:INVALID_FIELD_OVERRIDE*/B get f1 => null;
-  /*error:INVALID_FIELD_OVERRIDE*/B get f2 => null;
-  /*error:INVALID_FIELD_OVERRIDE*/B get f3 => null;
-  /*error:INVALID_FIELD_OVERRIDE*/B get f4 => null;
-  /*error:INVALID_FIELD_OVERRIDE*/B get f5 => null;
+  B get f1 => null;
+  B get f2 => null;
+  B get f3 => null;
+  B get f4 => null;
+  B get f5 => null;
 
-  /*error:INVALID_FIELD_OVERRIDE*/void set f1(A value) {}
-  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/void set f2(C value) {}
-  /*error:INVALID_FIELD_OVERRIDE*/void set f3(value) {}
-  /*error:INVALID_FIELD_OVERRIDE*/void set f4(dynamic value) {}
-  /*error:INVALID_FIELD_OVERRIDE*/set f5(B value) {}
+  void set f1(A value) {}
+  /*error:INVALID_METHOD_OVERRIDE*/void set f2(C value) {}
+  void set f3(value) {}
+  void set f4(dynamic value) {}
+  set f5(B value) {}
 }
 
 class Child2 implements Base {
@@ -2494,21 +2494,21 @@ class Base {
 }
 
 class T1 extends Base {
-  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE, error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/B get f => null;
+  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE,error:INVALID_METHOD_OVERRIDE*/B get f => null;
 }
 
 class T2 extends Base {
-  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE, error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/set f(
+  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE,error:INVALID_METHOD_OVERRIDE*/set f(
       B b) => null;
 }
 
 class T3 extends Base {
-  /*error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/final B
+  /*error:INVALID_METHOD_OVERRIDE*/final B
       /*warning:FINAL_NOT_INITIALIZED*/f;
 }
 class T4 extends Base {
   // two: one for the getter one for the setter.
-  /*error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/B f;
+  /*error:INVALID_METHOD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/B f;
 }
 
 class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE*/T5 implements Base {
@@ -2610,7 +2610,7 @@ class Parent extends Grandparent {
 
 class Test extends Parent {
     /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
-    /*error:INVALID_FIELD_OVERRIDE*/int x;
+    int x;
 }
 ''');
   }
@@ -2655,9 +2655,9 @@ class M2 {
 class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
     with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1 {}
 class /*error:INCONSISTENT_METHOD_INHERITANCE*/T2 extends Base
-    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1, /*error:INVALID_FIELD_OVERRIDE*/M2 {}
+    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1, M2 {}
 class /*error:INCONSISTENT_METHOD_INHERITANCE*/T3 extends Base
-    with /*error:INVALID_FIELD_OVERRIDE*/M2, /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1 {}
+    with M2, /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1 {}
 ''');
   }
 
@@ -2681,7 +2681,7 @@ class M2 {
 
 class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
     with M1,
-    /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN,error:INVALID_FIELD_OVERRIDE*/M2 {}
+    /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M2 {}
 ''');
   }
 
@@ -3294,8 +3294,8 @@ class Base {
 }
 
 class GrandChild extends main.Child {
-  /*error:INVALID_FIELD_OVERRIDE*/var _f2;
-  /*error:INVALID_FIELD_OVERRIDE*/var _f3;
+  var _f2;
+  var _f3;
   var _f4;
 
   /*error:INVALID_METHOD_OVERRIDE*/String _m1() => null;
@@ -3306,7 +3306,7 @@ class GrandChild extends main.Child {
 import 'helper.dart' as helper;
 
 class Child extends helper.Base {
-  /*error:INVALID_FIELD_OVERRIDE*/var f1;
+  var f1;
   var _f2;
   var _f4;
 

pkg/analyzer/test/src/task/strong/inferred_type_test.dart

@@ -3187,7 +3187,7 @@ main() {
   test_inferParameterType_setter_fromField() async {
     var mainUnit = await checkFileElement('''
 class C extends D {
-  /*error:INVALID_FIELD_OVERRIDE*/set foo(x) {}
+  set foo(x) {}
 }
 class D {
   int foo;
@@ -3601,7 +3601,7 @@ class A {
 }
 
 class B extends A {
-  /*error:INVALID_FIELD_OVERRIDE*/get x => 3;
+  get x => 3;
 }
 
 foo() {
@@ -3741,7 +3741,7 @@ class A<T> {
 
 class B<E> extends A<E> {
   E y;
-  /*error:INVALID_FIELD_OVERRIDE*/get x => y;
+  get x => y;
 }
 
 foo() {