diff --git a/include/clang/AST/Comment.h b/include/clang/AST/Comment.h
index 78b703d..f00993b 100644
--- a/include/clang/AST/Comment.h
+++ b/include/clang/AST/Comment.h
@@ -570,13 +570,16 @@
 
   /// Paragraph argument.
   ParagraphComment *Paragraph;
-
+  
+  /// Header Doc command, if true
+  bool HDCommand;
+  
   BlockCommandComment(CommentKind K,
                       SourceLocation LocBegin,
                       SourceLocation LocEnd,
                       unsigned CommandID) :
       BlockContentComment(K, LocBegin, LocEnd),
-      Paragraph(NULL) {
+      Paragraph(NULL), HDCommand(false) {
     setLocation(getCommandNameBeginLoc());
     BlockCommandCommentBits.CommandID = CommandID;
   }
@@ -586,7 +589,7 @@
                       SourceLocation LocEnd,
                       unsigned CommandID) :
       BlockContentComment(BlockCommandCommentKind, LocBegin, LocEnd),
-      Paragraph(NULL) {
+      Paragraph(NULL), HDCommand(false) {
     setLocation(getCommandNameBeginLoc());
     BlockCommandCommentBits.CommandID = CommandID;
   }
@@ -657,6 +660,14 @@
     if (NewLocEnd.isValid())
       setSourceRange(SourceRange(getLocStart(), NewLocEnd));
   }
+  
+  bool getHDCommand() const LLVM_READONLY {
+    return HDCommand;
+  }
+  
+  void setHDCommand(bool HDC) {
+    HDCommand = HDC;
+  }
 };
 
 /// Doxygen \\param command.
diff --git a/include/clang/AST/CommentLexer.h b/include/clang/AST/CommentLexer.h
index b90414b..240a8ea 100644
--- a/include/clang/AST/CommentLexer.h
+++ b/include/clang/AST/CommentLexer.h
@@ -75,6 +75,9 @@
   /// unused (command spelling can be found with CommandTraits).  Otherwise,
   /// contains the length of the string that starts at TextPtr.
   unsigned IntVal;
+  
+  /// This command is a Header Doc command (command starts with '@').
+  bool     HDCommand;
 
 public:
   SourceLocation getLocation() const LLVM_READONLY { return Loc; }
@@ -122,6 +125,10 @@
     return IntVal;
   }
 
+  bool getHDCommand() const LLVM_READONLY {
+    return HDCommand;
+  }
+  
   void setCommandID(unsigned ID) {
     assert(is(tok::command));
     IntVal = ID;
diff --git a/include/clang/Basic/DiagnosticCommentKinds.td b/include/clang/Basic/DiagnosticCommentKinds.td
index e6dfe5b..f8a2af3 100644
--- a/include/clang/Basic/DiagnosticCommentKinds.td
+++ b/include/clang/Basic/DiagnosticCommentKinds.td
@@ -44,18 +44,18 @@
 // Commands
 
 def warn_doc_block_command_empty_paragraph : Warning<
-  "empty paragraph passed to '\\%0' command">,
+  "empty paragraph passed to '%select{\\|@}0%1' command">,
   InGroup<Documentation>, DefaultIgnore;
 
 def warn_doc_block_command_duplicate : Warning<
-  "duplicated command '\\%0'">,
+  "duplicated command '%select{\\|@}0%1'">,
   InGroup<Documentation>, DefaultIgnore;
 
 def note_doc_block_command_previous : Note<
-  "previous command '\\%0' here">;
+  "previous command '%select{\\|@}0%1' here">;
 
 def note_doc_block_command_previous_alias : Note<
-  "previous command '\\%0' (an alias of '\\%1') here">;
+  "previous command '%select{\\|@}0%1' (an alias of '\\%2') here">;
 
 // \param command
 
@@ -111,14 +111,14 @@
 // \returns command
 
 def warn_doc_returns_not_attached_to_a_function_decl : Warning<
-  "'\\%0' command used in a comment that is not attached to "
+  "'%select{\\|@}0%1' command used in a comment that is not attached to "
   "a function or method declaration">,
   InGroup<Documentation>, DefaultIgnore;
 
 def warn_doc_returns_attached_to_a_void_function : Warning<
-  "'\\%0' command used in a comment that is attached to a "
+  "'%select{\\|@}0%1' command used in a comment that is attached to a "
   "%select{function returning void|constructor|destructor|"
-  "method returning void}1">,
+  "method returning void}2">,
   InGroup<Documentation>, DefaultIgnore;
 
 // \deprecated command
@@ -134,7 +134,7 @@
 // verbatim block commands
 
 def warn_verbatim_block_end_without_start : Warning<
-  "'\\%0' command does not terminate a verbatim text block">,
+  "'%select{\\|@}0%1' command does not terminate a verbatim text block">,
   InGroup<Documentation>, DefaultIgnore;
 
 } // end of documentation issue category
diff --git a/lib/AST/CommentLexer.cpp b/lib/AST/CommentLexer.cpp
index cee086e..da865d2 100644
--- a/lib/AST/CommentLexer.cpp
+++ b/lib/AST/CommentLexer.cpp
@@ -298,6 +298,7 @@
     switch(*TokenPtr) {
       case '\\':
       case '@': {
+        T.HDCommand = (*TokenPtr == '@');
         TokenPtr++;
         if (TokenPtr == CommentEnd) {
           formTextToken(T, TokenPtr);
diff --git a/lib/AST/CommentParser.cpp b/lib/AST/CommentParser.cpp
index 952c10c..f5c933e 100644
--- a/lib/AST/CommentParser.cpp
+++ b/lib/AST/CommentParser.cpp
@@ -313,15 +313,18 @@
     PC = S.actOnParamCommandStart(Tok.getLocation(),
                                   Tok.getEndLocation(),
                                   Tok.getCommandID());
+    PC->setHDCommand(Tok.getHDCommand());
   } else if (Info->IsTParamCommand) {
     IsTParam = true;
     TPC = S.actOnTParamCommandStart(Tok.getLocation(),
                                     Tok.getEndLocation(),
                                     Tok.getCommandID());
+    TPC->setHDCommand(Tok.getHDCommand());
   } else {
     BC = S.actOnBlockCommandStart(Tok.getLocation(),
                                   Tok.getEndLocation(),
                                   Tok.getCommandID());
+    BC->setHDCommand(Tok.getHDCommand());
   }
   consumeToken();
 
@@ -569,6 +572,7 @@
       if (Info->IsVerbatimBlockEndCommand) {
         Diag(Tok.getLocation(),
              diag::warn_verbatim_block_end_without_start)
+          << Tok.getHDCommand()
           << Info->Name
           << SourceRange(Tok.getLocation(), Tok.getEndLocation());
         consumeToken();
diff --git a/lib/AST/CommentSema.cpp b/lib/AST/CommentSema.cpp
index 73e49e7..3227138 100644
--- a/lib/AST/CommentSema.cpp
+++ b/lib/AST/CommentSema.cpp
@@ -432,6 +432,7 @@
     if (!DiagLoc.isValid())
       DiagLoc = Command->getCommandNameRange(Traits).getEnd();
     Diag(DiagLoc, diag::warn_doc_block_command_empty_paragraph)
+      << Command->getHDCommand()
       << Command->getCommandName(Traits)
       << Command->getSourceRange();
   }
@@ -459,6 +460,7 @@
       }
       Diag(Command->getLocation(),
            diag::warn_doc_returns_attached_to_a_void_function)
+        << Command->getHDCommand()
         << Command->getCommandName(Traits)
         << DiagKind
         << Command->getSourceRange();
@@ -470,6 +472,7 @@
   
   Diag(Command->getLocation(),
        diag::warn_doc_returns_not_attached_to_a_function_decl)
+    << Command->getHDCommand()
     << Command->getCommandName(Traits)
     << Command->getSourceRange();
 }
@@ -502,15 +505,18 @@
   StringRef CommandName = Command->getCommandName(Traits);
   StringRef PrevCommandName = PrevCommand->getCommandName(Traits);
   Diag(Command->getLocation(), diag::warn_doc_block_command_duplicate)
+      << Command->getHDCommand()
       << CommandName
       << Command->getSourceRange();
   if (CommandName == PrevCommandName)
     Diag(PrevCommand->getLocation(), diag::note_doc_block_command_previous)
+        << PrevCommand->getHDCommand()
         << PrevCommandName
         << PrevCommand->getSourceRange();
   else
     Diag(PrevCommand->getLocation(),
          diag::note_doc_block_command_previous_alias)
+        << PrevCommand->getHDCommand()
         << PrevCommandName
         << CommandName;
 }
diff --git a/test/Sema/warn-documentation.cpp b/test/Sema/warn-documentation.cpp
index e2e49e5..d166ae0 100644
--- a/test/Sema/warn-documentation.cpp
+++ b/test/Sema/warn-documentation.cpp
@@ -862,28 +862,28 @@
 
 // We used to crash on this.  PR15068
 
-// expected-warning@+2 {{empty paragraph passed to '\param' command}}
-// expected-warning@+2 {{empty paragraph passed to '\param' command}}
+// expected-warning@+2 {{empty paragraph passed to '@param' command}}
+// expected-warning@+2 {{empty paragraph passed to '@param' command}}
 ///@param x
 ///@param y
 int test_nocrash10(int x, int y);
 
-// expected-warning@+2 {{empty paragraph passed to '\param' command}} expected-warning@+2 {{parameter 'x' not found in the function declaration}}
-// expected-warning@+2 {{empty paragraph passed to '\param' command}} expected-warning@+2 {{parameter 'y' not found in the function declaration}}
+// expected-warning@+2 {{empty paragraph passed to '@param' command}} expected-warning@+2 {{parameter 'x' not found in the function declaration}}
+// expected-warning@+2 {{empty paragraph passed to '@param' command}} expected-warning@+2 {{parameter 'y' not found in the function declaration}}
 ///@param x
 ///@param y
 int test_nocrash11();
 
-// expected-warning@+3 {{empty paragraph passed to '\param' command}} expected-warning@+3 {{parameter 'x' not found in the function declaration}}
-// expected-warning@+3 {{empty paragraph passed to '\param' command}} expected-warning@+3 {{parameter 'y' not found in the function declaration}}
+// expected-warning@+3 {{empty paragraph passed to '@param' command}} expected-warning@+3 {{parameter 'x' not found in the function declaration}}
+// expected-warning@+3 {{empty paragraph passed to '@param' command}} expected-warning@+3 {{parameter 'y' not found in the function declaration}}
 /**
 @param x
 @param y
 **/
 int test_nocrash12();
 
-// expected-warning@+2 {{empty paragraph passed to '\param' command}}
-// expected-warning@+1 {{empty paragraph passed to '\param' command}}
+// expected-warning@+2 {{empty paragraph passed to '@param' command}}
+// expected-warning@+1 {{empty paragraph passed to '@param' command}}
 ///@param x@param y
 int test_nocrash13(int x, int y);
 
@@ -895,3 +895,15 @@
 /// \headerfile foo.h 
 int test_duplicate_headerfile1(int);
 
+
+// rdar://13066276
+// expected-warning@+1 {{'@return' command used in a comment that is not attached to a function or method declaration}}
+/** @return s */
+struct s* f(void);
+struct s;
+
+// expected-warning@+1 {{'\return' command used in a comment that is not attached to a function or method declaration}}
+/** \return s */
+struct q* g(void);
+struct q;
+