Verify type annotations on public APIs (#24).

lib/src/ast.dart

 // Copyright (c) 2015, 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.
 
 /// Common AST helpers.
 library linter.src.ast;
 
 import 'package:analyzer/src/generated/ast.dart'
     show
         AssignmentExpression,
         AstNode,
         Block,
         BlockFunctionBody,
         ClassDeclaration,
         ClassMember,
         ClassTypeAlias,
         ConstructorDeclaration,
         Declaration,
         EnumConstantDeclaration,
         EnumDeclaration,
         Expression,
         ExpressionFunctionBody,
         ExpressionStatement,
         FieldDeclaration,
         FunctionDeclaration,
         FunctionTypeAlias,
+        Identifier,
         MethodDeclaration,
         ReturnStatement,
         SimpleIdentifier,
         TopLevelVariableDeclaration,
         TypeParameter,
         VariableDeclaration;
 import 'package:analyzer/src/generated/element.dart'
     show
         Element,
         GeneralizingElementVisitor,
@@ skipping 199 matching lines @@
   }
   if (node is TypeParameter) {
     return node.name;
   }
   if (node is VariableDeclaration) {
     return node.name;
   }
   return null;
 }
 
+/// Check if the given identifier has a private name.
+bool isPrivate(SimpleIdentifier identifier) =>
+    identifier != null ? Identifier.isPrivateName(identifier.name) : false;
+
 /// An [Element] processor function type.
 /// If `true` is returned, children of [element] will be visited.
 typedef bool ElementProcessor(Element element);
 
 /// A [GeneralizingElementVisitor] adapter for [ElementProcessor].
 class _ElementVisitorAdapter extends GeneralizingElementVisitor {
   final ElementProcessor processor;
   _ElementVisitorAdapter(this.processor);
 
   @override
   void visitElement(Element element) {
     bool visitChildren = processor(element);
     if (visitChildren == true) {
       element.visitChildren(this);
     }
   }
 }