Re-land "Add support for metadata on type variables to Fasta parser." (with fixes).

pkg/front_end/lib/src/fasta/analyzer/ast_builder.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.
 
 library fasta.analyzer.ast_builder;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast_factory.dart' show AstFactory;
 import 'package:analyzer/dart/ast/standard_ast_factory.dart' as standard;
 import 'package:analyzer/dart/ast/token.dart' as analyzer show Token;
@@ skipping 144 matching lines @@
   }
 
   void endArguments(int count, Token beginToken, Token endToken) {
     debugEvent("Arguments");
     List expressions = popList(count);
     ArgumentList arguments = ast.argumentList(
         toAnalyzerToken(beginToken), expressions, toAnalyzerToken(endToken));
     push(ast.methodInvocation(null, null, null, null, arguments));
   }
 
+  void endMetadata(Token beginToken, Token periodBeforeName, Token endToken) {

[Paul Berry, 2017/03/15 16:14:52]

Note: Konstantin introduced an implementation of this method in
08eba174cc9d5ba028f9f0d53a35f1d2190d834e, so it is no longer needed in this CL.

+    debugEvent("Metadata");
+    ArgumentList arguments = pop();
+    SimpleIdentifier constructorName = popIfNotNull(periodBeforeName);
+    var typeArguments = pop();
+    assert(typeArguments == null); // TODO(paulberry)
+    Identifier name = pop();
+    push(ast.annotation(toAnalyzerToken(beginToken), name,
+        toAnalyzerToken(periodBeforeName), constructorName, arguments));
+  }
+
   void handleIdentifier(Token token, IdentifierContext context) {
     debugEvent("handleIdentifier");
     analyzer.Token analyzerToken = toAnalyzerToken(token);
 
     if (context.inSymbol) {
       push(analyzerToken);
       return;
     }
 
     SimpleIdentifier identifier = ast.simpleIdentifier(analyzerToken,
@@ skipping 1205 matching lines @@
 
   @override
   void endTypeVariable(Token token, Token extendsOrSuper) {
     // TODO(paulberry): set up scopes properly to resolve parameters and type
     // variables.  Note that this is tricky due to the handling of initializers
     // in constructors, so the logic should be shared with BodyBuilder as much
     // as possible.
     debugEvent("TypeVariable");
     TypeAnnotation bound = pop();
     SimpleIdentifier name = pop();
-    List<Annotation> metadata = null; // TODO(paulberry)
-    // TODO(paulberry): capture doc comments.  See dartbug.com/28851.
-    Comment comment = null;
+    List<Annotation> metadata = pop();
+    Comment comment = pop();
     push(ast.typeParameter(
         comment, metadata, name, toAnalyzerToken(extendsOrSuper), bound));
   }
 
   @override
   void endTypeVariables(int count, Token beginToken, Token endToken) {
     debugEvent("TypeVariables");
     List<TypeParameter> typeParameters = popList(count);
     push(ast.typeParameterList(toAnalyzerToken(beginToken), typeParameters,
         toAnalyzerToken(endToken)));
@@ skipping 322 matching lines @@
       } else if (identical('static', s)) {
         staticKeyword = token;
       } else if (identical('var', s)) {
         finalConstOrVarKeyword = token;
       } else {
         internalError('Unhandled modifier: $s');
       }
     }
   }
 }