diff --git a/clang/include/clang/AST/CommentSema.h b/clang/include/clang/AST/CommentSema.h
--- a/clang/include/clang/AST/CommentSema.h
+++ b/clang/include/clang/AST/CommentSema.h
@@ -188,7 +188,9 @@
 
   /// Emit diagnostics about duplicate block commands that should be
   /// used only once per comment, e.g., \and \\returns.
-  void checkBlockCommandDuplicate(const BlockCommandComment *Command);
+  void
+  checkBlockCommandDuplicate(const BlockCommandComment *Command,
+                             const BlockCommandComment *Sema::*LastOccurrence);
 
   void checkDeprecatedCommand(const BlockCommandComment *Comment);
 
diff --git a/clang/lib/AST/CommentSema.cpp b/clang/lib/AST/CommentSema.cpp
--- a/clang/lib/AST/CommentSema.cpp
+++ b/clang/lib/AST/CommentSema.cpp
@@ -55,7 +55,9 @@
   BlockCommandComment *BC = new (Allocator) BlockCommandComment(LocBegin, LocEnd,
                                                                 CommandID,
                                                                 CommandMarker);
-  checkContainerDecl(BC);
+  const CommandInfo *Info = Traits.getCommandInfo(CommandID);
+  if (Info->IsRecordLikeDetailCommand)
+    checkContainerDecl(BC);
   return BC;
 }
 
@@ -67,13 +69,20 @@
 void Sema::actOnBlockCommandFinish(BlockCommandComment *Command,
                                    ParagraphComment *Paragraph) {
   Command->setParagraph(Paragraph);
-  checkBlockCommandEmptyParagraph(Command);
-  checkBlockCommandDuplicate(Command);
+  const CommandInfo *Info = Traits.getCommandInfo(Command->getCommandID());
+  if (!Info->IsEmptyParagraphAllowed)
+    checkBlockCommandEmptyParagraph(Command);
+  if (Info->IsBriefCommand)
+    checkBlockCommandDuplicate(Command, &Sema::BriefCommand);
+  else if (Info->IsHeaderfileCommand)
+    checkBlockCommandDuplicate(Command, &Sema::HeaderfileCommand);
   if (ThisDeclInfo) {
     // These checks only make sense if the comment is attached to a
     // declaration.
-    checkReturnsCommand(Command);
-    checkDeprecatedCommand(Command);
+    if (Info->IsReturnsCommand)
+      checkReturnsCommand(Command);
+    if (Info->IsDeprecatedCommand)
+      checkDeprecatedCommand(Command);
   }
 }
 
@@ -96,10 +105,6 @@
 }
 
 void Sema::checkFunctionDeclVerbatimLine(const BlockCommandComment *Comment) {
-  const CommandInfo *Info = Traits.getCommandInfo(Comment->getCommandID());
-  if (!Info->IsFunctionDeclarationCommand)
-    return;
-
   unsigned DiagSelect;
   switch (Comment->getCommandID()) {
     case CommandTraits::KCI_function:
@@ -129,9 +134,6 @@
 }
 
 void Sema::checkContainerDeclVerbatimLine(const BlockCommandComment *Comment) {
-  const CommandInfo *Info = Traits.getCommandInfo(Comment->getCommandID());
-  if (!Info->IsRecordLikeDeclarationCommand)
-    return;
   unsigned DiagSelect;
   switch (Comment->getCommandID()) {
     case CommandTraits::KCI_class:
@@ -168,8 +170,7 @@
 }
 
 void Sema::checkContainerDecl(const BlockCommandComment *Comment) {
-  const CommandInfo *Info = Traits.getCommandInfo(Comment->getCommandID());
-  if (!Info->IsRecordLikeDetailCommand || isRecordLikeDecl())
+  if (isRecordLikeDecl())
     return;
   unsigned DiagSelect;
   switch (Comment->getCommandID()) {
@@ -275,6 +276,8 @@
 void Sema::actOnParamCommandFinish(ParamCommandComment *Command,
                                    ParagraphComment *Paragraph) {
   Command->setParagraph(Paragraph);
+  assert(
+      !Traits.getCommandInfo(Command->getCommandID())->IsEmptyParagraphAllowed);
   checkBlockCommandEmptyParagraph(Command);
 }
 
@@ -358,6 +361,8 @@
 void Sema::actOnTParamCommandFinish(TParamCommandComment *Command,
                                     ParagraphComment *Paragraph) {
   Command->setParagraph(Paragraph);
+  assert(
+      !Traits.getCommandInfo(Command->getCommandID())->IsEmptyParagraphAllowed);
   checkBlockCommandEmptyParagraph(Command);
 }
 
@@ -450,8 +455,12 @@
                               CommandID,
                               TextBegin,
                               Text);
-  checkFunctionDeclVerbatimLine(VL);
-  checkContainerDeclVerbatimLine(VL);
+
+  const CommandInfo *Info = Traits.getCommandInfo(CommandID);
+  if (Info->IsFunctionDeclarationCommand)
+    checkFunctionDeclVerbatimLine(VL);
+  if (Info->IsRecordLikeDeclarationCommand)
+    checkContainerDeclVerbatimLine(VL);
   return VL;
 }
 
@@ -561,9 +570,6 @@
 }
 
 void Sema::checkBlockCommandEmptyParagraph(BlockCommandComment *Command) {
-  if (Traits.getCommandInfo(Command->getCommandID())->IsEmptyParagraphAllowed)
-    return;
-
   ParagraphComment *Paragraph = Command->getParagraph();
   if (Paragraph->isWhitespace()) {
     SourceLocation DiagLoc;
@@ -579,9 +585,6 @@
 }
 
 void Sema::checkReturnsCommand(const BlockCommandComment *Command) {
-  if (!Traits.getCommandInfo(Command->getCommandID())->IsReturnsCommand)
-    return;
-
   assert(ThisDeclInfo && "should not call this check on a bare comment");
 
   // We allow the return command for all @properties because it can be used
@@ -624,25 +627,16 @@
     << Command->getSourceRange();
 }
 
-void Sema::checkBlockCommandDuplicate(const BlockCommandComment *Command) {
-  const CommandInfo *Info = Traits.getCommandInfo(Command->getCommandID());
+void Sema::checkBlockCommandDuplicate(
+    const BlockCommandComment *Command,
+    const BlockCommandComment *Sema::*LastOccurrence) {
   const BlockCommandComment *PrevCommand = nullptr;
-  if (Info->IsBriefCommand) {
-    if (!BriefCommand) {
-      BriefCommand = Command;
-      return;
-    }
-    PrevCommand = BriefCommand;
-  } else if (Info->IsHeaderfileCommand) {
-    if (!HeaderfileCommand) {
-      HeaderfileCommand = Command;
-      return;
-    }
-    PrevCommand = HeaderfileCommand;
-  } else {
-    // We don't want to check this command for duplicates.
+  if (!(this->*LastOccurrence)) {
+    this->*LastOccurrence = Command;
     return;
   }
+  PrevCommand = this->*LastOccurrence;
+
   StringRef CommandName = Command->getCommandName(Traits);
   StringRef PrevCommandName = PrevCommand->getCommandName(Traits);
   Diag(Command->getLocation(), diag::warn_doc_block_command_duplicate)
@@ -663,9 +657,6 @@
 }
 
 void Sema::checkDeprecatedCommand(const BlockCommandComment *Command) {
-  if (!Traits.getCommandInfo(Command->getCommandID())->IsDeprecatedCommand)
-    return;
-
   assert(ThisDeclInfo && "should not call this check on a bare comment");
 
   const Decl *D = ThisDeclInfo->CommentDecl;