Elements. Write more ElementImpl as references, not as fragments.

Change-Id: Id41267ca30bb04a79156d106b87bdc08f0566673
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/431781
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -110,7 +110,7 @@ testFineAfterLibraryAnalyzerHook;
 // TODO(scheglov): Clean up the list of implicitly analyzed files.
 class AnalysisDriver {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 461;
+  static const int DATA_VERSION = 462;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/dart/constant/evaluation.dart

@@ -3026,6 +3026,7 @@ class _InstanceCreationEvaluator {
   ///
   /// Returns an [InvalidConstant] if one is found, or `null` otherwise.
   InvalidConstant? _checkFields() {
+    var substitution = Substitution.fromInterfaceType(_constructor.returnType);
     var fields = _constructor.declaration.enclosingElement3.fields;
     for (var field in fields) {
       if ((field.isFinal || field.isConst) &&
@@ -3040,7 +3041,7 @@ class _InstanceCreationEvaluator {
           continue;
         }
         // Match the value and the type.
-        var fieldType = FieldMember.from(field, _constructor.returnType).type;
+        var fieldType = substitution.substituteType(field.type);
         if (!typeSystem.runtimeTypeMatch(fieldValue, fieldType)) {
           var isRuntimeException = hasTypeParameterReference(field.type);
           var errorNode = field.constantInitializer ?? _errorNode;

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

@@ -7642,9 +7642,6 @@ class MixinElementImpl2 extends InterfaceElementImpl2 implements MixinElement {
   @override
   final MixinFragmentImpl firstFragment;
 
-  @override
-  List<InterfaceTypeImpl> superclassConstraints = [];
-
   MixinElementImpl2(this.reference, this.firstFragment) {
     reference.element2 = this;
     firstFragment.augmentedInternal = this;
@@ -7665,6 +7662,11 @@ class MixinElementImpl2 extends InterfaceElementImpl2 implements MixinElement {
   @override
   bool get isBase => firstFragment.isBase;
 
+  @override
+  List<InterfaceTypeImpl> get superclassConstraints {
+    return [for (var fragment in fragments) ...fragment.superclassConstraints];
+  }
+
   /// Names of methods, getters, setters, and operators that this mixin
   /// declaration super-invokes.  For setters this includes the trailing "=".
   /// The list will be empty if this class is not a mixin declaration.

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

@@ -615,21 +615,16 @@ class FieldMember extends VariableMember
   @override
   void visitChildren2<T>(ElementVisitor2<T> visitor) {}
 
-  /// If the given [element]'s type is different when any type parameters from the
-  /// defining type's declaration are replaced with the actual type arguments
-  /// from the [definingType], create a field member representing the given
-  /// field. Return the member that was created, or the base field if no member
-  /// was created.
-  static FieldElementOrMember from(
-    FieldFragmentImpl element,
-    InterfaceType definingType,
+  static FieldElement2OrMember from(
+    FieldElementImpl2 element,
+    MapSubstitution substitution,
   ) {
-    if (definingType.typeArguments.isEmpty) {
+    if (substitution.map.isEmpty) {
       return element;
     }
     return FieldMember(
-      declaration: element,
-      substitution: Substitution.fromInterfaceType(definingType),
+      declaration: element.firstFragment,
+      substitution: substitution,
     );
   }
 

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

@@ -16,8 +16,16 @@ enum DirectiveUriKind {
   withNothing,
 }
 
-// TODO(scheglov): remove once we untangle Element2 from Fragment in storage.
-enum ElementKind2 { importPrefix, other }
+enum ElementTag {
+  null_,
+  dynamic_,
+  never_,
+  multiplyDefined,
+  memberWithTypeArguments,
+  elementImpl,
+  // TODO(scheglov): remove once we untangle Element2 from Fragment in storage.
+  viaFragment,
+}
 
 enum ImportElementPrefixKind { isDeferred, isNotDeferred, isNull }
 

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

@@ -230,16 +230,16 @@ abstract class InstanceElementBuilder<
   }
 
   void _addFirstFragment() {
-    var firstFragment = this.firstFragment;
-    var element = firstFragment.element;
-
-    if (element is MixinElementImpl2) {
-      if (firstFragment is MixinFragmentImpl) {
-        element.superclassConstraints.addAll(
-          firstFragment.superclassConstraints,
-        );
-      }
-    }
+    // TODO(scheglov): restore eventually
+    // var firstFragment = this.firstFragment;
+    // var element = firstFragment.element;
+    // if (element is MixinElementImpl2) {
+    //   if (firstFragment is MixinFragmentImpl) {
+    //     element.superclassConstraints.addAll(
+    //       firstFragment.superclassConstraints,
+    //     );
+    //   }
+    // }
   }
 }
 

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

@@ -1894,9 +1894,6 @@ class MixinElementLinkedData extends ElementLinkedData<MixinFragmentImpl> {
     element.superclassConstraints = reader._readInterfaceTypeList();
     element.interfaces = reader._readInterfaceTypeList();
 
-    var augmented = element.augmentedInternal;
-    augmented.superclassConstraints = reader._readInterfaceTypeList();
-
     applyConstantOffsets?.perform();
   }
 }
@@ -1962,13 +1959,37 @@ class ResolutionReader {
   }
 
   Element? readElement() {
-    var kind = readEnum(ElementKind2.values);
+    var kind = readEnum(ElementTag.values);
     switch (kind) {
-      case ElementKind2.importPrefix:
+      case ElementTag.null_:
+        return null;
+      case ElementTag.dynamic_:
+        return DynamicElementImpl2.instance;
+      case ElementTag.never_:
+        return NeverElementImpl2.instance;
+      case ElementTag.multiplyDefined:
+        return null;
+      case ElementTag.memberWithTypeArguments:
+        var elementImpl = readElement() as ElementImpl2;
+        var enclosing = elementImpl.enclosingElement as InstanceElementImpl2;
+
+        var typeArguments = _readTypeList();
+        var substitution = Substitution.fromPairs2(
+          enclosing.typeParameters2,
+          typeArguments,
+        );
+
+        if (elementImpl is ExecutableElementImpl2) {
+          return ExecutableMember.from(elementImpl, substitution);
+        } else {
+          elementImpl as FieldElementImpl2;
+          return FieldMember.from(elementImpl, substitution);
+        }
+      case ElementTag.elementImpl:
         var referenceIndex = _reader.readUInt30();
         var reference = _referenceReader.referenceOfIndex(referenceIndex);
-        return reference.element2 as PrefixElementImpl2;
-      case ElementKind2.other:
+        return _elementFactory.elementOfReference3(reference);
+      case ElementTag.viaFragment:
         // TODO(scheglov): eventually stop using fragments here.
         var fragment = readFragmentOrMember();
         switch (fragment) {

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

@@ -451,9 +451,6 @@ class BundleWriter {
       _resolutionSink._writeTypeList(fragment.superclassConstraints);
       _resolutionSink._writeTypeList(fragment.interfaces);
 
-      var element = fragment.element;
-      _resolutionSink._writeTypeList(element.superclassConstraints);
-
       _writeList(
         fragment.fields.where((e) => !e.isSynthetic).toList(),
         _writeFieldElement,
@@ -698,33 +695,46 @@ class ResolutionSink extends _SummaryDataWriter {
     required _BundleWriterReferences references,
   }) : _references = references;
 
-  // TODO(scheglov): Triage places where we write elements.
-  // Some of then cannot be members, e.g. type names.
   void writeElement(Element? element) {
     switch (element) {
-      case PrefixElementImpl2():
-        writeEnum(ElementKind2.importPrefix);
-        var reference = element.reference;
+      case null:
+        writeEnum(ElementTag.null_);
+      case DynamicElementImpl2():
+        writeEnum(ElementTag.dynamic_);
+      case NeverElementImpl2():
+        writeEnum(ElementTag.never_);
+      case MultiplyDefinedElementImpl2():
+        writeEnum(ElementTag.multiplyDefined);
+      case Member element:
+        writeEnum(ElementTag.memberWithTypeArguments);
+
+        var baseElement = element.baseElement;
+        writeElement(baseElement);
+
+        var typeArguments = _enclosingClassTypeArguments(
+          baseElement,
+          element.substitution.map,
+        );
+        _writeTypeList(typeArguments);
+      // TODO(scheglov): give reference to each element below
+      case ConstructorElementImpl2():
+      case FieldElementImpl2():
+      case FormalParameterElementImpl():
+      case GetterElementImpl():
+      case MethodElementImpl2():
+      case SetterElementImpl():
+      case TypeParameterElementImpl2():
+        // TODO(scheglov): eventually stop using fragments here.
+        writeEnum(ElementTag.viaFragment);
+        writeByte(Tag.RawElement);
+        _writeElement(element);
+      case ElementImpl2():
+        writeEnum(ElementTag.elementImpl);
+        var reference = element.reference!;
         var referenceIndex = _references._indexOfReference(reference);
         writeUInt30(referenceIndex);
       default:
-        // TODO(scheglov): eventually stop using fragments here.
-        writeEnum(ElementKind2.other);
-        if (element case Member element) {
-          var baseElement = element.baseElement;
-
-          var typeArguments = _enclosingClassTypeArguments(
-            baseElement,
-            element.substitution.map,
-          );
-
-          writeByte(Tag.MemberWithTypeArguments);
-          _writeElement(baseElement);
-          _writeTypeList(typeArguments);
-        } else {
-          writeByte(Tag.RawElement);
-          _writeElement(element);
-        }
+        throw StateError('${element.runtimeType}');
     }
   }
 

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

@@ -354,7 +354,6 @@ class LibraryBuilder {
           if (element.superclassConstraints.isEmpty) {
             shouldResetClassHierarchies = true;
             interfaceFragment.superclassConstraints = [objectType];
-            element.superclassConstraints = [objectType];
           }
       }
     }

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

@@ -106,12 +106,9 @@ class LinkedElementFactory {
     return Namespace(exportedNames);
   }
 
-  LibraryElementImpl? createLibraryElementForReading(Uri uri) {
+  LibraryElementImpl createLibraryElementForReading(Uri uri) {
     var sourceFactory = analysisContext.sourceFactory;
-    var librarySource = sourceFactory.forUri2(uri);
-
-    // The URI cannot be resolved, we don't know the library.
-    if (librarySource == null) return null;
+    var librarySource = sourceFactory.forUri2(uri)!;
 
     var reader = _libraryReaders[uri];
     if (reader == null) {
@@ -206,6 +203,31 @@ class LinkedElementFactory {
     return elementOfReference(reference)?.asElement2;
   }
 
+  Element elementOfReference3(Reference reference) {
+    if (reference.element2 case var element?) {
+      return element;
+    }
+
+    if (reference.isLibrary) {
+      var uri = uriCache.parse(reference.name);
+      return createLibraryElementForReading(uri);
+    }
+
+    var parentRef = reference.parentNotContainer;
+    var parentElement = elementOfReference(parentRef);
+
+    // Only classes delay creating children.
+    if (parentElement is ClassFragmentImpl) {
+      parentElement.linkedData?.readMembers(parentElement);
+    }
+
+    var element = reference.element2;
+    if (element == null) {
+      throw StateError('Expected existing element: $reference');
+    }
+    return element;
+  }
+
   bool hasLibrary(Uri uri) {
     // We already have the element, linked or read.
     if (rootReference['$uri']?.element is LibraryElementImpl) {