Parse documentation for class aliases, fix for /// comments.

pkg/front_end/lib/src/fasta/source/outline_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.outline_builder;
 
 import 'package:kernel/ast.dart' show ProcedureKind;
 
 import '../../scanner/token.dart' show Token;
 
@@ skipping 267 matching lines @@
 
   @override
   void endClassDeclaration(
       int interfacesCount,
       Token beginToken,
       Token classKeyword,
       Token extendsKeyword,
       Token implementsKeyword,
       Token endToken) {
     debugEvent("endClassDeclaration");
-
-    String documentationComment = null;
-    if (beginToken.precedingComments != null) {
-      documentationComment = beginToken.precedingComments.lexeme;
-      // TODO(scheglov): Add support for line comments.
-    }
-
+    String documentationComment = _getDocumentationComment(beginToken);
     List<TypeBuilder> interfaces = popList(interfacesCount);
     TypeBuilder supertype = pop();
     List<TypeVariableBuilder> typeVariables = pop();
     int charOffset = pop();
     String name = pop();
     if (typeVariables != null && supertype is MixinApplicationBuilder) {
       supertype.typeVariables = typeVariables;
       supertype.subclassName = name;
     }
     int modifiers = Modifier.validate(pop());
@@ skipping 152 matching lines @@
     List<TypeBuilder> mixins = pop();
     TypeBuilder supertype = pop();
     push(
         library.addMixinApplication(supertype, mixins, withKeyword.charOffset));
   }
 
   @override
   void endNamedMixinApplication(Token beginToken, Token classKeyword,
       Token equals, Token implementsKeyword, Token endToken) {
     debugEvent("endNamedMixinApplication");
+    String documentationComment = _getDocumentationComment(beginToken);
     List<TypeBuilder> interfaces = popIfNotNull(implementsKeyword);
     TypeBuilder mixinApplication = pop();
     List<TypeVariableBuilder> typeVariables = pop();
     int charOffset = pop();
     String name = pop();
     int modifiers = Modifier.validate(pop());
     List<MetadataBuilder> metadata = pop();
-    library.addNamedMixinApplication(metadata, name, typeVariables, modifiers,
-        mixinApplication, interfaces, charOffset);
+    library.addNamedMixinApplication(documentationComment, metadata, name,
+        typeVariables, modifiers, mixinApplication, interfaces, charOffset);
     checkEmpty(beginToken.charOffset);
   }
 
   @override
   void endTypeArguments(int count, Token beginToken, Token endToken) {
     debugEvent("TypeArguments");
     push(popList(count) ?? NullValue.TypeArguments);
   }
 
   @override
@@ skipping 423 matching lines @@
   void addCompileTimeError(Message message, int charOffset) {
     library.addCompileTimeError(message, charOffset, uri);
   }
 
   @override
   Link<Token> handleMemberName(Link<Token> identifiers) {
     if (!enableNative || identifiers.isEmpty) return identifiers;
     return removeNativeClause(identifiers, stringExpectedAfterNative);
   }
 
+  /// Return the documentation comment for the entity that starts at the
+  /// given [token], or `null` if there is no preceding documentation comment.
+  String _getDocumentationComment(Token token) {
+    Token docToken = token.precedingComments;
+    if (docToken == null) return null;
+    var buffer = new StringBuffer();
+    while (docToken != null) {
+      String lexeme = docToken.lexeme;
+      if (lexeme.startsWith('///') || lexeme.startsWith('/**')) {

[Siggi Cherem (dart-lang), 2017/07/24 17:34:47]

I understand that the reason for this loop is to ensure comments like:
 /// line A1
 /// line A2

include both A1 and A2 (not just A1).

But it seems we are also concatenating to dartdocs like /** */ for example:
 /** line B1 */
 /** line B2 */

Is this the intent? Or is the dartdoc only supposed to be line B2 in this case?

If so, let's update the logic here accordingly.

Either way, let's add a test to ensure we are tracking the behavior we want.

[scheglov, 2017/07/24 19:13:38]

Done.

+        if (buffer.isNotEmpty) {
+          buffer.writeln();
+        }
+        buffer.write(lexeme);
+      }
+      docToken = docToken.next;
+    }
+    return buffer.toString();
+  }
+
   @override
   void debugEvent(String name) {
     // printEvent(name);
   }
 }