Compute subtyped names.

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

 // Copyright (c) 2016, 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.
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 
 /**
  * Compute the set of external names referenced in the [unit].
  */
 Set<String> computeReferencedNames(CompilationUnit unit) {
   _ReferencedNamesComputer computer = new _ReferencedNamesComputer();
   unit.accept(computer);
   return computer.names;
 }
 
 /**
+ * Compute the set of names which are used in `extends`, `with` or `implements`
+ * clauses in the file. Import prefixes and type arguments are not included.
+ */
+Set<String> computeSubtypedNames(CompilationUnit unit) {
+  Set<String> subtypedNames = new Set<String>();
+
+  void _addSubtypedName(TypeName type) {
+    if (type != null) {
+      Identifier name = type.name;
+      if (name is SimpleIdentifier) {
+        subtypedNames.add(name.name);
+      } else if (name is PrefixedIdentifier) {
+        subtypedNames.add(name.identifier.name);
+      }
+    }
+  }
+
+  void _addSubtypedNames(List<TypeName> types) {
+    types?.forEach(_addSubtypedName);
+  }
+
+  for (CompilationUnitMember declaration in unit.declarations) {
+    if (declaration is ClassDeclaration) {
+      _addSubtypedName(declaration.extendsClause?.superclass);
+      _addSubtypedNames(declaration.withClause?.mixinTypes);
+      _addSubtypedNames(declaration.implementsClause?.interfaces);
+    }
+  }
+
+  return subtypedNames;
+}
+
+/**
  * Chained set of local names, that hide corresponding external names.
  */
 class _LocalNameScope {
   final _LocalNameScope enclosing;
   Set<String> names;
 
   _LocalNameScope(this.enclosing);
 
   factory _LocalNameScope.forBlock(_LocalNameScope enclosing, Block node) {
     _LocalNameScope scope = new _LocalNameScope(enclosing);
@@ skipping 241 matching lines @@
   }
 
   static bool _isNameExpressionLabel(AstNode parent) {
     if (parent is Label) {
       AstNode parent2 = parent?.parent;
       return parent2 is NamedExpression && parent2.name == parent;
     }
     return false;
   }
 }