Macro. Code optimizer. Update initializers of final fields, when has const constructor.

Change-Id: I7a0097e240c2e54c47e6a24cb07054f656950ea8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/353582
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Phil Quitslund <pquitslund@google.com>

Author: scheglov

pkg/analyzer/lib/src/summary2/library_builder.dart

@@ -191,7 +191,7 @@ class LibraryBuilder {
   /// The fields that were speculatively created as [ConstFieldElementImpl],
   /// but we want to clear [ConstVariableElement.constantInitializer] for it
   /// if the class will not end up with a `const` constructor. We don't know
-  /// at the time when we create them, because of future augmentations, use
+  /// at the time when we create them, because of future augmentations, user
   /// written or macro generated.
   final Set<ConstFieldElementImpl> finalInstanceFields = Set.identity();
 
@@ -555,6 +555,7 @@ class LibraryBuilder {
       augmentation: augmentation,
     ).perform(updateConstants: () {
       MacroUpdateConstantsForOptimizedCode(
+        libraryElement: element,
         unitNode: mergedUnit,
         codeEdits: optimizedCodeEdits,
         unitElement: unitElement,

pkg/analyzer/lib/src/summary2/macro_merge.dart

@@ -235,6 +235,9 @@ class MacroElementsMerger {
 }
 
 class MacroUpdateConstantsForOptimizedCode {
+  /// The container of [unitElement].
+  final LibraryElementImpl libraryElement;
+
   /// The parsed merged code.
   final ast.CompilationUnit unitNode;
 
@@ -245,7 +248,11 @@ class MacroUpdateConstantsForOptimizedCode {
   /// The merged element, with elements in the same order as in [unitNode].
   final CompilationUnitElementImpl unitElement;
 
+  /// The names of classes that have a `const` constructor.
+  final Set<String> _namesOfConstClasses = {};
+
   MacroUpdateConstantsForOptimizedCode({
+    required this.libraryElement,
     required this.unitNode,
     required this.codeEdits,
     required this.unitElement,
@@ -263,6 +270,7 @@ class MacroUpdateConstantsForOptimizedCode {
   /// The same elements, in the same order.
   /// If not, we have a bug in [MacroElementsMerger].
   void perform() {
+    _findConstClasses();
     var nodeRecords = _orderedForNodes();
     var elementRecords = _orderedForElement();
     assert(nodeRecords.length == elementRecords.length);
@@ -295,6 +303,21 @@ class MacroUpdateConstantsForOptimizedCode {
     }
   }
 
+  void _findConstClasses() {
+    for (var element in libraryElement.topLevelElements) {
+      if (element is! ClassElementImpl) continue;
+      if (element.isAugmentation) continue;
+
+      var augmented = element.augmented;
+      if (augmented == null) continue;
+
+      var hasConst = augmented.constructors.any((e) => e.isConst);
+      if (hasConst) {
+        _namesOfConstClasses.add(element.name);
+      }
+    }
+  }
+
   List<(ElementImpl, ast.AstNodeImpl)> _orderedForElement() {
     var result = <(ElementImpl, ast.AstNodeImpl)>[];
 
@@ -390,22 +413,31 @@ class MacroUpdateConstantsForOptimizedCode {
 
     void addVariableList(
       ast.VariableDeclarationListImpl variableList,
-      List<ast.AnnotationImpl> metadata,
-    ) {
+      List<ast.AnnotationImpl> metadata, {
+      required bool withFinals,
+    }) {
       for (var variable in variableList.variables) {
         addMetadata(variable, metadata);
-        if (variableList.isConst) {
+
+        if (variableList.isConst || variableList.isFinal && withFinals) {
           if (variable.initializer case var initializer?) {
             result.add((variable, initializer));
           }
         }
       }
     }
 
-    void addInterfaceMembers(List<ast.ClassMemberImpl> members) {
+    void addInterfaceMembers(
+      List<ast.ClassMemberImpl> members, {
+      required bool hasConstConstructor,
+    }) {
       for (var field in members) {
         if (field is ast.FieldDeclarationImpl) {
-          addVariableList(field.fields, field.metadata);
+          addVariableList(
+            field.fields,
+            field.metadata,
+            withFinals: hasConstConstructor && !field.isStatic,
+          );
         }
       }
 
@@ -438,13 +470,22 @@ class MacroUpdateConstantsForOptimizedCode {
     for (var class_ in unitNode.declarations) {
       if (class_ is ast.ClassDeclarationImpl) {
         addAnnotatedNode(class_);
-        addInterfaceMembers(class_.members);
+        addInterfaceMembers(
+          class_.members,
+          hasConstConstructor: _namesOfConstClasses.contains(
+            class_.name.lexeme,
+          ),
+        );
       }
     }
 
     for (var topVariable in unitNode.declarations) {
       if (topVariable is ast.TopLevelVariableDeclarationImpl) {
-        addVariableList(topVariable.variables, topVariable.metadata);
+        addVariableList(
+          topVariable.variables,
+          topVariable.metadata,
+          withFinals: false,
+        );
       }
     }
 

pkg/analyzer/test/src/summary/macro_test.dart

@@ -2861,7 +2861,7 @@ augment class A {
 ''');
   }
 
-  test_codeOptimizer_constant_classField_constant() async {
+  test_codeOptimizer_constant_classField_const() async {
     newFile('$testPackageLibPath/a.dart', r'''
 const a = 0;
 ''');
@@ -2913,6 +2913,107 @@ augment class B {
 ''');
   }
 
+  test_codeOptimizer_constant_classField_final_hasConstConstructor() async {
+    newFile('$testPackageLibPath/a.dart', r'''
+const a = 0;
+''');
+
+    var library = await buildLibrary(r'''
+import 'append.dart';
+import 'a.dart';
+
+@DeclareInType('  final x = {{package:test/a.dart@a}};')
+class B {
+  const B();
+}
+''');
+
+    configuration.forCodeOptimizer();
+    checkElementText(library, r'''
+library
+  imports
+    package:test/append.dart
+    package:test/a.dart
+  augmentationImports
+    package:test/test.macro.dart
+      macroGeneratedCode
+---
+library augment 'test.dart';
+
+import 'package:test/a.dart';
+
+augment class B {
+  final x = a;
+}
+---
+      imports
+        package:test/a.dart
+      definingUnit
+        classes
+          augment class B @75
+            augmentationTarget: self::@class::B
+            fields
+              final x @87
+                type: int
+                shouldUseTypeForInitializerInference: false
+                constantInitializer
+                  SimpleIdentifier
+                    token: a @91
+                    staticElement: package:test/a.dart::@getter::a
+                    staticType: int
+            accessors
+              synthetic get x @-1
+                returnType: int
+''');
+  }
+
+  test_codeOptimizer_constant_classField_final_noConstConstructor() async {
+    newFile('$testPackageLibPath/a.dart', r'''
+const a = 0;
+''');
+
+    var library = await buildLibrary(r'''
+import 'append.dart';
+import 'a.dart';
+
+@DeclareInType('  final x = {{package:test/a.dart@a}};')
+class B {}
+''');
+
+    configuration.forCodeOptimizer();
+    checkElementText(library, r'''
+library
+  imports
+    package:test/append.dart
+    package:test/a.dart
+  augmentationImports
+    package:test/test.macro.dart
+      macroGeneratedCode
+---
+library augment 'test.dart';
+
+import 'package:test/a.dart';
+
+augment class B {
+  final x = a;
+}
+---
+      imports
+        package:test/a.dart
+      definingUnit
+        classes
+          augment class B @75
+            augmentationTarget: self::@class::B
+            fields
+              final x @87
+                type: int
+                shouldUseTypeForInitializerInference: false
+            accessors
+              synthetic get x @-1
+                returnType: int
+''');
+  }
+
   test_codeOptimizer_constant_classField_namedType() async {
     newFile('$testPackageLibPath/a.dart', r'''
 class A<T> {}