libray imported extensions

Change-Id: Ibe2f772886b42cf0ccc577a55106dc33cf690b7c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108662
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

pkg/analyzer/lib/src/dart/resolver/scope.dart

@@ -364,6 +364,11 @@ class LibraryImportScope extends Scope {
    */
   Map<String, Map<String, Element>> _definedPrefixedNames;
 
+  /**
+   * Cache of public extensions defined in this library's imported namespaces.
+   */
+  List<ExtensionElement> _extensions;
+
   /**
    * Initialize a newly created scope representing the names imported into the
    * [_definingLibrary].
@@ -372,6 +377,22 @@ class LibraryImportScope extends Scope {
     _createImportedNamespaces();
   }
 
+  @override
+  List<ExtensionElement> get extensions {
+    if (_extensions == null) {
+      _extensions = [];
+      for (var namespace in _importedNamespaces) {
+        for (var element in namespace.definedNames.values) {
+          if (element is ExtensionElement &&
+              element.name.isNotEmpty /* named */) {
+            _extensions.add(element);
+          }
+        }
+      }
+    }
+    return _extensions;
+  }
+
   @override
   void define(Element element) {
     if (!Scope.isPrivateName(element.displayName)) {
@@ -579,7 +600,8 @@ class LibraryScope extends EnclosedScope {
   }
 
   @override
-  List<ExtensionElement> get extensions => _extensions;
+  List<ExtensionElement> get extensions =>
+      enclosingScope.extensions.toList()..addAll(_extensions);
 
   /**
    * Add to this scope all of the public top-level names that are defined in the
@@ -776,6 +798,9 @@ class NamespaceBuilder {
     for (ClassElement element in compilationUnit.enums) {
       _addIfPublic(definedNames, element);
     }
+    for (ExtensionElement element in compilationUnit.extensions) {
+      _addIfPublic(definedNames, element);
+    }
     for (FunctionElement element in compilationUnit.functions) {
       _addIfPublic(definedNames, element);
     }

pkg/analyzer/test/generated/resolver_test.dart

@@ -275,6 +275,35 @@ class LibraryImportScopeTest extends ResolverTestCase {
         importedType);
   }
 
+  void test_extensions_imported() {
+    var context = AnalysisContextFactory.contextWithCore(
+        resourceProvider: resourceProvider);
+
+    var extension = ExtensionElementImpl.forNode(
+        AstTestFactory.identifier3('test_extension'));
+
+    var importedUnit1 = ElementFactory.compilationUnit('/imported1.dart');
+    importedUnit1.extensions = <ExtensionElement>[extension];
+
+    var importedLibraryName = 'imported_lib';
+    var importedLibrary = LibraryElementImpl(context, null, importedLibraryName,
+        0, importedLibraryName.length, false);
+    importedLibrary.definingCompilationUnit = importedUnit1;
+
+    var importingLibraryName = 'importing_lib';
+    var importingLibrary = LibraryElementImpl(context, null,
+        importingLibraryName, 0, importingLibraryName.length, false);
+    importingLibrary.definingCompilationUnit =
+        ElementFactory.compilationUnit('/importing.dart');
+
+    var importElement = ImportElementImpl(0);
+    importElement.importedLibrary = importedLibrary;
+    importingLibrary.imports = <ImportElement>[importElement];
+
+    expect(
+        LibraryImportScope(importingLibrary).extensions, contains(extension));
+  }
+
   void test_prefixedAndNonPrefixed() {
     AnalysisContext context = AnalysisContextFactory.contextWithCore(
         resourceProvider: resourceProvider);
@@ -352,6 +381,43 @@ class LibraryScopeTest extends ResolverTestCase {
 
     expect(LibraryScope(library).extensions, contains(extension));
   }
+
+  void test_extensions_imported() {
+    var context = AnalysisContextFactory.contextWithCore(
+        resourceProvider: resourceProvider);
+
+    var importedUnit1 = ElementFactory.compilationUnit('/imported1.dart');
+    var importedExtension = ExtensionElementImpl.forNode(
+        AstTestFactory.identifier3('test_extension'));
+    var unnamedImportedExtension = ExtensionElementImpl.forNode(null);
+    importedUnit1.extensions = [importedExtension, unnamedImportedExtension];
+
+    var importedLibraryName = 'imported_lib';
+    var importedLibrary = LibraryElementImpl(context, null, importedLibraryName,
+        0, importedLibraryName.length, false);
+    importedLibrary.definingCompilationUnit = importedUnit1;
+
+    var importingLibraryName = 'importing_lib';
+    var importingLibrary = LibraryElementImpl(context, null,
+        importingLibraryName, 0, importingLibraryName.length, false);
+
+    var localExtension = ExtensionElementImpl.forNode(
+        AstTestFactory.identifier3('test_extension'));
+
+    var importingUnit = ElementFactory.compilationUnit('/importing.dart');
+    importingUnit.extensions = [localExtension];
+    importingLibrary.definingCompilationUnit = importingUnit;
+
+    var importElement = ImportElementImpl(0);
+    importElement.importedLibrary = importedLibrary;
+    importingLibrary.imports = [importElement];
+
+    var libraryExtensions = LibraryScope(importingLibrary).extensions;
+
+    expect(libraryExtensions, contains(localExtension));
+    expect(libraryExtensions, contains(importedExtension));
+    expect(libraryExtensions, isNot(contains(unnamedImportedExtension)));
+  }
 }
 
 @reflectiveTest