Augment. Support multiple augmentations of the same element in the sa…

…me container.

The same mechanism is now also used to handle (not allowed) duplicate
declarations.

Change-Id: I814abcb15b7f2e7248701f754b7af1fdcb74f31a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/328900
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

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

@@ -88,7 +88,7 @@ import 'package:analyzer/src/utilities/uri_cache.dart';
 /// TODO(scheglov) Clean up the list of implicitly analyzed files.
 class AnalysisDriver implements AnalysisDriverGeneric {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 310;
+  static const int DATA_VERSION = 311;
 
   /// 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/element/display_string_builder.dart

@@ -299,6 +299,12 @@ class ElementDisplayStringBuilder {
   }
 
   void writeVariableElement(VariableElement element) {
+    switch (element) {
+      case FieldElement(isAugmentation: true):
+      case TopLevelVariableElement(isAugmentation: true):
+        _write('augment ');
+    }
+
     _writeType(element.type);
     _write(' ');
     _write(element.displayName);

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

@@ -6375,6 +6375,19 @@ abstract class PropertyInducingElementImpl
     setModifier(Modifier.SHOULD_USE_TYPE_FOR_INITIALIZER_INFERENCE, true);
   }
 
+  /// Return `true` if this variable needs the setter.
+  bool get hasSetter {
+    if (isConst) {
+      return false;
+    }
+
+    if (isLate) {
+      return !isFinal || !hasInitializer;
+    }
+
+    return !isFinal;
+  }
+
   @override
   bool get isConstantEvaluated => true;
 
@@ -6450,36 +6463,26 @@ abstract class PropertyInducingElementImpl
     return _type!;
   }
 
-  /// Return `true` if this variable needs the setter.
-  bool get _hasSetter {
-    if (isConst) {
-      return false;
-    }
-
-    if (isLate) {
-      return !isFinal || !hasInitializer;
-    }
-
-    return !isFinal;
-  }
-
   void bindReference(Reference reference) {
     this.reference = reference;
     reference.element = this;
   }
 
-  void createImplicitAccessors(Reference enclosingRef, String name) {
-    getter = PropertyAccessorElementImpl_ImplicitGetter(
+  PropertyAccessorElementImpl createImplicitGetter(Reference reference) {
+    assert(getter == null);
+    return getter = PropertyAccessorElementImpl_ImplicitGetter(
       this,
-      reference: enclosingRef.getChild('@getter').getChild(name),
+      reference: reference,
     );
+  }
 
-    if (_hasSetter) {
-      setter = PropertyAccessorElementImpl_ImplicitSetter(
-        this,
-        reference: enclosingRef.getChild('@setter').getChild(name),
-      );
-    }
+  PropertyAccessorElementImpl createImplicitSetter(Reference reference) {
+    assert(hasSetter);
+    assert(setter == null);
+    return setter = PropertyAccessorElementImpl_ImplicitSetter(
+      this,
+      reference: reference,
+    );
   }
 
   void setLinkedData(Reference reference, ElementLinkedData linkedData) {

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

@@ -717,7 +717,7 @@ class LibraryReader {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
 
     final reference = _readReference();
-    final name = reference.name;
+    final name = reference.elementName;
 
     var element = ClassElementImpl(name, -1);
 
@@ -790,7 +790,7 @@ class LibraryReader {
     return _reader.readTypedList(() {
       var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
       final reference = _readReference();
-      final name = reference.name.ifEqualThen('new', '');
+      final name = reference.elementName.ifEqualThen('new', '');
       var element = ConstructorElementImpl(name, -1);
       var linkedData = ConstructorElementLinkedData(
         reference: reference,
@@ -895,7 +895,7 @@ class LibraryReader {
   ) {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
     final reference = _readReference();
-    final name = reference.name;
+    final name = reference.elementName;
 
     var element = EnumElementImpl(name, -1);
 
@@ -980,7 +980,7 @@ class LibraryReader {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
 
     final reference = _readReference();
-    final name = _reader.readBool() ? reference.name : null;
+    final name = _reader.readBool() ? reference.elementName : null;
 
     var element = ExtensionElementImpl(name, -1);
     element.setLinkedData(
@@ -1023,7 +1023,7 @@ class LibraryReader {
   ) {
     final resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
     final reference = _readReference();
-    final name = reference.name;
+    final name = reference.elementName;
 
     final element = ExtensionTypeElementImpl(name, -1);
     element.setLinkedData(
@@ -1073,8 +1073,12 @@ class LibraryReader {
     Reference classReference,
   ) {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
+
     final reference = _readReference();
-    final name = reference.name;
+    final getterReference = _readOptionalReference();
+    final setterReference = _readOptionalReference();
+
+    final name = reference.elementName;
     var isConstElement = _reader.readBool();
 
     FieldElementImpl element;
@@ -1096,7 +1100,12 @@ class LibraryReader {
     element.typeInferenceError = _readTopLevelInferenceError();
 
     if (!element.isAugmentation) {
-      element.createImplicitAccessors(classReference, name);
+      if (getterReference != null) {
+        element.createImplicitGetter(getterReference);
+      }
+      if (element.hasSetter && setterReference != null) {
+        element.createImplicitSetter(setterReference);
+      }
     }
 
     return element;
@@ -1136,7 +1145,7 @@ class LibraryReader {
     unitElement.functions = _reader.readTypedList(() {
       var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
       final reference = _readReference();
-      final name = reference.name;
+      final name = reference.elementName;
 
       var element = FunctionElementImpl(name, -1);
 
@@ -1258,7 +1267,7 @@ class LibraryReader {
     return _reader.readTypedList(() {
       var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
       final reference = _readReference();
-      final name = reference.name;
+      final name = reference.elementName;
       var element = MethodElementImpl(name, -1);
       var linkedData = MethodElementLinkedData(
         reference: reference,
@@ -1281,7 +1290,7 @@ class LibraryReader {
   ) {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
     final reference = _readReference();
-    final name = reference.name;
+    final name = reference.elementName;
 
     var element = MixinElementImpl(name, -1);
 
@@ -1335,18 +1344,24 @@ class LibraryReader {
     }
   }
 
+  /// Read the reference of a non-local element.
+  Reference? _readOptionalReference() {
+    return _reader.readOptionalObject(
+      (reader) => _readReference(),
+    );
+  }
+
   /// TODO(scheglov) Deduplicate parameter reading implementation.
   List<ParameterElementImpl> _readParameters(
     ElementImpl enclosingElement,
     Reference enclosingReference,
   ) {
-    var containerRef = enclosingReference.getChild('@parameter');
     return _reader.readTypedList(() {
       var name = _reader.readStringReference();
       var isDefault = _reader.readBool();
       var isInitializingFormal = _reader.readBool();
       var isSuperFormal = _reader.readBool();
-      var reference = containerRef.getChild(name);
+      var reference = _readReference();
 
       var kindIndex = _reader.readByte();
       var kind = ResolutionReader._formalParameterKind(kindIndex);
@@ -1445,7 +1460,7 @@ class LibraryReader {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
 
     final reference = _readReference();
-    final name = reference.name;
+    final name = reference.elementName;
 
     var element = PropertyAccessorElementImpl(name, -1);
     PropertyAccessorElementFlags.read(_reader, element);
@@ -1557,8 +1572,12 @@ class LibraryReader {
     Reference unitReference,
   ) {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
+
     final reference = _readReference();
-    final name = reference.name;
+    final getterReference = _readOptionalReference();
+    final setterReference = _readOptionalReference();
+
+    final name = reference.elementName;
     var isConst = _reader.readBool();
 
     TopLevelVariableElementImpl element;
@@ -1579,7 +1598,13 @@ class LibraryReader {
     element.isConst = isConst;
     TopLevelVariableElementFlags.read(_reader, element);
     element.typeInferenceError = _readTopLevelInferenceError();
-    element.createImplicitAccessors(unitReference, name);
+
+    if (getterReference != null) {
+      element.createImplicitGetter(getterReference);
+    }
+    if (element.hasSetter && setterReference != null) {
+      element.createImplicitSetter(setterReference);
+    }
 
     return element;
   }
@@ -1613,7 +1638,7 @@ class LibraryReader {
   ) {
     var resolutionOffset = _baseResolutionOffset + _reader.readUInt30();
     final reference = _readReference();
-    final name = reference.name;
+    final name = reference.elementName;
 
     var isFunctionTypeAliasBased = _reader.readBool();
 

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

@@ -378,6 +378,8 @@ class BundleWriter {
   void _writeFieldElement(FieldElementImpl element) {
     _sink.writeUInt30(_resolutionSink.offset);
     _writeReference(element);
+    _writeOptionalReference(element.getter);
+    _writeOptionalReference(element.setter);
     _sink.writeBool(element is ConstFieldElementImpl);
     FieldElementFlags.write(_sink, element);
     _sink._writeTopLevelInferenceError(element.typeInferenceError);
@@ -559,13 +561,21 @@ class BundleWriter {
     }
   }
 
+  /// Write the reference of a non-local element.
+  void _writeOptionalReference(ElementImpl? element) {
+    _sink.writeOptionalObject(element, (element) {
+      _writeReference(element);
+    });
+  }
+
   /// TODO(scheglov) Deduplicate parameter writing implementation.
   void _writeParameterElement(ParameterElement element) {
     element as ParameterElementImpl;
     _sink._writeStringReference(element.name);
     _sink.writeBool(element is ConstVariableElement);
     _sink.writeBool(element.isInitializingFormal);
     _sink.writeBool(element.isSuperFormal);
+    _writeReference(element);
     _sink._writeFormalParameterKind(element);
     ParameterElementFlags.write(_sink, element);
 
@@ -623,6 +633,8 @@ class BundleWriter {
   void _writeTopLevelVariableElement(TopLevelVariableElementImpl element) {
     _sink.writeUInt30(_resolutionSink.offset);
     _writeReference(element);
+    _writeOptionalReference(element.getter);
+    _writeOptionalReference(element.setter);
     _sink.writeBool(element.isConst);
     TopLevelVariableElementFlags.write(_sink, element);
     _sink._writeTopLevelInferenceError(element.typeInferenceError);