[cfe] Fix Field.isCovariantByClass for fields without implicit setters

TEST=pkg/vm/testcases/transformations/type_flow/transformer/regress_57084.dart
Fixes #57084

Change-Id: Id2a411c3be22e60f8d1a24db0098f3d72369434c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/396300
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>

Author: alexmarkov

pkg/front_end/lib/src/kernel/member_covariance.dart

@@ -41,7 +41,7 @@ class Covariance {
     if ((covariance & Covariant) != 0) {
       field.isCovariantByDeclaration = true;
     }
-    if ((covariance & GenericCovariantImpl) != 0) {
+    if (((covariance & GenericCovariantImpl) != 0) && field.hasSetter) {
       field.isCovariantByClass = true;
     }
   }

pkg/front_end/lib/src/source/source_field_builder.dart

@@ -814,7 +814,9 @@ class RegularFieldEncoding implements FieldEncoding {
 
   @override
   void setGenericCovariantImpl() {
-    _field.isCovariantByClass = true;
+    if (_field.hasSetter) {
+      _field.isCovariantByClass = true;
+    }
   }
 
   @override
@@ -1175,7 +1177,9 @@ abstract class AbstractLateFieldEncoding implements FieldEncoding {
 
   @override
   void setGenericCovariantImpl() {
-    _field.isCovariantByClass = true;
+    if (_field.hasSetter) {
+      _field.isCovariantByClass = true;
+    }
     _lateSetter?.function.positionalParameters.single.isCovariantByClass = true;
   }
 

pkg/front_end/testcases/nnbd/issue40600.dart.strong.expect

@@ -12,7 +12,7 @@ class B<Y extends core::Object? = dynamic> extends core::Object {
   method bar(covariant-by-class FutureOr<self::B::Y%>y) → dynamic {}
 }
 class A<X extends core::Object? = dynamic> extends core::Object {
-  covariant-by-class final field self::B<self::A::X%> b = new self::B::•<self::A::X%>();
+  final field self::B<self::A::X%> b = new self::B::•<self::A::X%>();
   synthetic constructor •() → self::A<self::A::X%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/nnbd/issue40600.dart.strong.modular.expect

@@ -12,7 +12,7 @@ class B<Y extends core::Object? = dynamic> extends core::Object {
   method bar(covariant-by-class FutureOr<self::B::Y%>y) → dynamic {}
 }
 class A<X extends core::Object? = dynamic> extends core::Object {
-  covariant-by-class final field self::B<self::A::X%> b = new self::B::•<self::A::X%>();
+  final field self::B<self::A::X%> b = new self::B::•<self::A::X%>();
   synthetic constructor •() → self::A<self::A::X%>
     : super core::Object::•()
     ;

pkg/front_end/testcases/nnbd/issue40600.dart.strong.outline.expect

@@ -11,7 +11,7 @@ class B<Y extends core::Object? = dynamic> extends core::Object {
     ;
 }
 class A<X extends core::Object? = dynamic> extends core::Object {
-  covariant-by-class final field self::B<self::A::X%> b;
+  final field self::B<self::A::X%> b;
   synthetic constructor •() → self::A<self::A::X%>
     ;
   method foo([covariant-by-class FutureOr<self::A::X%>? x = null]) → dynamic

pkg/front_end/testcases/nnbd/issue40600.dart.strong.transformed.expect

@@ -12,7 +12,7 @@ class B<Y extends core::Object? = dynamic> extends core::Object {
   method bar(covariant-by-class FutureOr<self::B::Y%>y) → dynamic {}
 }
 class A<X extends core::Object? = dynamic> extends core::Object {
-  covariant-by-class final field self::B<self::A::X%> b = new self::B::•<self::A::X%>();
+  final field self::B<self::A::X%> b = new self::B::•<self::A::X%>();
   synthetic constructor •() → self::A<self::A::X%>
     : super core::Object::•()
     ;

pkg/vm/testcases/transformations/type_flow/transformer/regress_57084.dart

@@ -0,0 +1,32 @@
+// Copyright (c) 2024, 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.
+
+// Regression test for https://github.com/dart-lang/sdk/issues/57084.
+// Verifies that summmary collector is not called recursively
+// when recording a constant field which is incorrectly marked
+// as isCovariantByClass and needs type guard summary.
+
+abstract class A<T> {
+  T get field;
+  void set field(T value);
+}
+
+class C<T> implements A<T> {
+  @override
+  final T field;
+
+  const C(this.field);
+
+  @override
+  set field(value) => throw '';
+}
+
+const c = C<String>('');
+
+void main() {
+  print(c);
+  () {
+    print(c);
+  }();
+}

pkg/vm/testcases/transformations/type_flow/transformer/regress_57084.dart.expect

@@ -0,0 +1,25 @@
+library #lib;
+import self as self;
+import "dart:core" as core;
+
+abstract class A<T extends core::Object? = dynamic> extends core::Object {
+}
+class C<T extends core::Object? = dynamic> extends core::Object implements self::A<self::C::T%> /*hasConstConstructor*/  {
+
+  [@vm.inferred-type.metadata=dart.core::_OneByteString (value: "")]
+  [@vm.procedure-attributes.metadata=methodOrSetterCalledDynamically:false,getterCalledDynamically:false,hasThisUses:false,hasNonThisUses:false,hasTearOffUses:false,getterSelectorId:1]
+  final field self::C::T% field;
+}
+
+[@vm.inferred-return-type.metadata=dart.core::Null? (value: null)]
+[@vm.closure-id=1]
+static method main() → void {
+  core::print(#C2);
+  [@vm.direct-call.metadata=closure 1 in #lib::main] [@vm.inferred-type.metadata=!? (receiver not int)]([@vm.closure-id=1]() → Null {
+    core::print(#C2);
+  })(){() → Null};
+}
+constants  {
+  #C1 = ""
+  #C2 = self::C<core::String> {field:#C1}
+}

pkg/vm/testcases/transformations/type_flow/transformer/regress_flutter147239.dart

@@ -7,7 +7,7 @@
 // for a field which has initializer with closure and captured receiver.
 
 class Foo<T> {
-  late final aField = () {
+  late var aField = () {
     return <T>[];
   };
 }

pkg/vm/testcases/transformations/type_flow/transformer/regress_flutter147239.dart.expect

@@ -5,9 +5,9 @@ import "dart:core" as core;
 class Foo<T extends core::Object? = dynamic> extends core::Object {
 
   [@vm.inferred-type.metadata=dart.core::_Closure (closure 1 in #lib::Foo.aField)]
-  [@vm.procedure-attributes.metadata=methodOrSetterCalledDynamically:false,getterCalledDynamically:false,hasThisUses:false,hasNonThisUses:false,hasTearOffUses:false,getterSelectorId:1]
+  [@vm.procedure-attributes.metadata=methodOrSetterCalledDynamically:false,getterCalledDynamically:false,hasThisUses:false,hasNonThisUses:false,hasTearOffUses:false,methodOrSetterSelectorId:1,getterSelectorId:2]
   [@vm.closure-id=1]
-  late covariant-by-class final field () → core::List<self::Foo::T%> aField = [@vm.closure-id=1]() → core::List<self::Foo::T%> {
+  late covariant-by-class field () → core::List<self::Foo::T%> aField = [@vm.closure-id=1]() → core::List<self::Foo::T%> {
     return [@vm.inferred-type.metadata=dart.core::_GrowableList<dart.core::String>] core::_GrowableList::•<self::Foo::T%>(0);
   };
   synthetic constructor •() → self::Foo<self::Foo::T%>