[Clang][Comments] Add argument parsing for @throw @throws @exception (#84726)

hdoc · web-flow · commit fade04f81da9 · 2024-06-10T23:00:00.000+02:00
Doxygen allows for the `@throw`, `@throws`, and `@exception` commands to
have an attached argument indicating the type being thrown. Currently,
Clang's AST parsing doesn't support parsing out this argument from doc
comments. The result is missing compatibility with Doxygen.

This PR implements parsing of arguments for the `@throw`, `@throws`, and
`@exception` commands. Each command can only have one argument, matching
the semantics of Doxygen.
diff --git a/clang/include/clang/AST/CommentCommands.td b/clang/include/clang/AST/CommentCommands.td
@@ -132,9 +132,9 @@ def Tparam : BlockCommand<"tparam"> { let IsTParamCommand = 1; }
 // HeaderDoc command for template parameter documentation.
 def Templatefield : BlockCommand<"templatefield"> { let IsTParamCommand = 1; }
 
-def Throws    : BlockCommand<"throws"> { let IsThrowsCommand = 1; }
-def Throw     : BlockCommand<"throw"> { let IsThrowsCommand = 1; }
-def Exception : BlockCommand<"exception"> { let IsThrowsCommand = 1; }
+def Throws    : BlockCommand<"throws"> { let IsThrowsCommand = 1; let NumArgs = 1; }
+def Throw     : BlockCommand<"throw"> { let IsThrowsCommand = 1; let NumArgs = 1; }
+def Exception : BlockCommand<"exception"> { let IsThrowsCommand = 1; let NumArgs = 1;}
 
 def Deprecated : BlockCommand<"deprecated"> {
   let IsEmptyParagraphAllowed = 1;
diff --git a/clang/include/clang/AST/CommentParser.h b/clang/include/clang/AST/CommentParser.h
@@ -100,6 +100,11 @@ class Parser {
   ArrayRef<Comment::Argument>
   parseCommandArgs(TextTokenRetokenizer &Retokenizer, unsigned NumArgs);
 
+  /// Parse arguments for \throws command supported args are in form of class
+  /// or template.
+  ArrayRef<Comment::Argument>
+  parseThrowCommandArgs(TextTokenRetokenizer &Retokenizer, unsigned NumArgs);
+
   BlockCommandComment *parseBlockCommand();
   InlineCommandComment *parseInlineCommand();
 
diff --git a/clang/lib/AST/CommentParser.cpp b/clang/lib/AST/CommentParser.cpp
@@ -89,6 +89,31 @@ class TextTokenRetokenizer {
     }
   }
 
+  /// Extract a template type
+  bool lexTemplate(SmallString<32> &WordText) {
+    unsigned BracketCount = 0;
+    while (!isEnd()) {
+      const char C = peek();
+      WordText.push_back(C);
+      consumeChar();
+      switch (C) {
+      case '<': {
+        BracketCount++;
+        break;
+      }
+      case '>': {
+        BracketCount--;
+        if (!BracketCount)
+          return true;
+        break;
+      }
+      default:
+        break;
+      }
+    }
+    return false;
+  }
+
   /// Add a token.
   /// Returns true on success, false if there are no interesting tokens to
   /// fetch from lexer.
@@ -149,6 +174,54 @@ class TextTokenRetokenizer {
     addToken();
   }
 
+  /// Extract a type argument
+  bool lexType(Token &Tok) {
+    if (isEnd())
+      return false;
+
+    // Save current position in case we need to rollback because the type is
+    // empty.
+    Position SavedPos = Pos;
+
+    // Consume any leading whitespace.
+    consumeWhitespace();
+    SmallString<32> WordText;
+    const char *WordBegin = Pos.BufferPtr;
+    SourceLocation Loc = getSourceLocation();
+
+    while (!isEnd()) {
+      const char C = peek();
+      // For non-whitespace characters we check if it's a template or otherwise
+      // continue reading the text into a word.
+      if (!isWhitespace(C)) {
+        if (C == '<') {
+          if (!lexTemplate(WordText))
+            return false;
+        } else {
+          WordText.push_back(C);
+          consumeChar();
+        }
+      } else {
+        consumeChar();
+        break;
+      }
+    }
+
+    const unsigned Length = WordText.size();
+    if (Length == 0) {
+      Pos = SavedPos;
+      return false;
+    }
+
+    char *TextPtr = Allocator.Allocate<char>(Length + 1);
+
+    memcpy(TextPtr, WordText.c_str(), Length + 1);
+    StringRef Text = StringRef(TextPtr, Length);
+
+    formTokenWithChars(Tok, Loc, WordBegin, Length, Text);
+    return true;
+  }
+
   /// Extract a word -- sequence of non-whitespace characters.
   bool lexWord(Token &Tok) {
     if (isEnd())
@@ -304,6 +377,23 @@ Parser::parseCommandArgs(TextTokenRetokenizer &Retokenizer, unsigned NumArgs) {
   return llvm::ArrayRef(Args, ParsedArgs);
 }
 
+ArrayRef<Comment::Argument>
+Parser::parseThrowCommandArgs(TextTokenRetokenizer &Retokenizer,
+                              unsigned NumArgs) {
+  auto *Args = new (Allocator.Allocate<Comment::Argument>(NumArgs))
+      Comment::Argument[NumArgs];
+  unsigned ParsedArgs = 0;
+  Token Arg;
+
+  while (ParsedArgs < NumArgs && Retokenizer.lexType(Arg)) {
+    Args[ParsedArgs] = Comment::Argument{
+        SourceRange(Arg.getLocation(), Arg.getEndLocation()), Arg.getText()};
+    ParsedArgs++;
+  }
+
+  return llvm::ArrayRef(Args, ParsedArgs);
+}
+
 BlockCommandComment *Parser::parseBlockCommand() {
   assert(Tok.is(tok::backslash_command) || Tok.is(tok::at_command));
 
@@ -356,6 +446,9 @@ BlockCommandComment *Parser::parseBlockCommand() {
       parseParamCommandArgs(PC, Retokenizer);
     else if (TPC)
       parseTParamCommandArgs(TPC, Retokenizer);
+    else if (Info->IsThrowsCommand)
+      S.actOnBlockCommandArgs(
+          BC, parseThrowCommandArgs(Retokenizer, Info->NumArgs));
     else
       S.actOnBlockCommandArgs(BC, parseCommandArgs(Retokenizer, Info->NumArgs));
 
diff --git a/clang/lib/Index/CommentToXML.cpp b/clang/lib/Index/CommentToXML.cpp
@@ -546,7 +546,8 @@ class CommentASTToXMLConverter :
   void visitParagraphComment(const ParagraphComment *C);
 
   void appendParagraphCommentWithKind(const ParagraphComment *C,
-                                      StringRef Kind);
+                                      StringRef ParagraphKind,
+                                      StringRef PrependBodyText);
 
   void visitBlockCommandComment(const BlockCommandComment *C);
   void visitParamCommandComment(const ParamCommandComment *C);
@@ -680,24 +681,27 @@ CommentASTToXMLConverter::visitHTMLEndTagComment(const HTMLEndTagComment *C) {
   Result << ">&lt;/" << C->getTagName() << "&gt;</rawHTML>";
 }
 
-void
-CommentASTToXMLConverter::visitParagraphComment(const ParagraphComment *C) {
-  appendParagraphCommentWithKind(C, StringRef());
+void CommentASTToXMLConverter::visitParagraphComment(
+    const ParagraphComment *C) {
+  appendParagraphCommentWithKind(C, StringRef(), StringRef());
 }
 
 void CommentASTToXMLConverter::appendParagraphCommentWithKind(
-                                  const ParagraphComment *C,
-                                  StringRef ParagraphKind) {
-  if (C->isWhitespace())
+    const ParagraphComment *C, StringRef ParagraphKind,
+    StringRef PrependBodyText) {
+  if (C->isWhitespace() && PrependBodyText.empty())
     return;
 
   if (ParagraphKind.empty())
     Result << "<Para>";
   else
     Result << "<Para kind=\"" << ParagraphKind << "\">";
 
-  for (Comment::child_iterator I = C->child_begin(), E = C->child_end();
-       I != E; ++I) {
+  if (!PrependBodyText.empty())
+    Result << PrependBodyText << " ";
+
+  for (Comment::child_iterator I = C->child_begin(), E = C->child_end(); I != E;
+       ++I) {
     visit(*I);
   }
   Result << "</Para>";
@@ -706,8 +710,15 @@ void CommentASTToXMLConverter::appendParagraphCommentWithKind(
 void CommentASTToXMLConverter::visitBlockCommandComment(
     const BlockCommandComment *C) {
   StringRef ParagraphKind;
+  StringRef ExceptionType;
 
-  switch (C->getCommandID()) {
+  const unsigned CommandID = C->getCommandID();
+  const CommandInfo *Info = Traits.getCommandInfo(CommandID);
+  if (Info->IsThrowsCommand && C->getNumArgs() > 0) {
+    ExceptionType = C->getArgText(0);
+  }
+
+  switch (CommandID) {
   case CommandTraits::KCI_attention:
   case CommandTraits::KCI_author:
   case CommandTraits::KCI_authors:
@@ -732,7 +743,8 @@ void CommentASTToXMLConverter::visitBlockCommandComment(
     break;
   }
 
-  appendParagraphCommentWithKind(C->getParagraph(), ParagraphKind);
+  appendParagraphCommentWithKind(C->getParagraph(), ParagraphKind,
+                                 ExceptionType);
 }
 
 void CommentASTToXMLConverter::visitParamCommandComment(
diff --git a/clang/test/Index/comment-to-html-xml-conversion.cpp b/clang/test/Index/comment-to-html-xml-conversion.cpp
@@ -1046,82 +1046,101 @@ void comment_to_xml_conversion_todo_4();
 /// Aaa.
 /// \throws Bbb.
 void comment_to_xml_conversion_exceptions_1();
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_1:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_1</Name><USR>c:@F@comment_to_xml_conversion_exceptions_1#</USR><Declaration>void comment_to_xml_conversion_exceptions_1()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para> Bbb.</Para></Exceptions></Function>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_1:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_1</Name><USR>c:@F@comment_to_xml_conversion_exceptions_1#</USR><Declaration>void comment_to_xml_conversion_exceptions_1()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb. </Para></Exceptions></Function>]
 // CHECK-NEXT:  CommentAST=[
 // CHECK-NEXT:    (CXComment_FullComment
 // CHECK-NEXT:       (CXComment_Paragraph
 // CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
 // CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws]
-// CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Bbb.]))))]
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Bbb.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace)))]
 
 /// Aaa.
 /// \throw Bbb.
 void comment_to_xml_conversion_exceptions_2();
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_2:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_2</Name><USR>c:@F@comment_to_xml_conversion_exceptions_2#</USR><Declaration>void comment_to_xml_conversion_exceptions_2()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para> Bbb.</Para></Exceptions></Function>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_2:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_2</Name><USR>c:@F@comment_to_xml_conversion_exceptions_2#</USR><Declaration>void comment_to_xml_conversion_exceptions_2()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb. </Para></Exceptions></Function>]
 // CHECK-NEXT:  CommentAST=[
 // CHECK-NEXT:    (CXComment_FullComment
 // CHECK-NEXT:       (CXComment_Paragraph
 // CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
 // CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throw]
-// CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Bbb.]))))]
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throw] Arg[0]=Bbb.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace)))]
 
 /// Aaa.
 /// \exception Bbb.
 void comment_to_xml_conversion_exceptions_3();
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_3:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_3</Name><USR>c:@F@comment_to_xml_conversion_exceptions_3#</USR><Declaration>void comment_to_xml_conversion_exceptions_3()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para> Bbb.</Para></Exceptions></Function>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_3:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_3</Name><USR>c:@F@comment_to_xml_conversion_exceptions_3#</USR><Declaration>void comment_to_xml_conversion_exceptions_3()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb. </Para></Exceptions></Function>]
 // CHECK-NEXT:  CommentAST=[
 // CHECK-NEXT:    (CXComment_FullComment
 // CHECK-NEXT:       (CXComment_Paragraph
 // CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
 // CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[exception]
-// CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Bbb.]))))]
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[exception] Arg[0]=Bbb.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace)))]
 
 /// Aaa.
 /// \throws Bbb.
 /// \throws Ccc.
 /// \throws Ddd.
 void comment_to_xml_conversion_exceptions_4();
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_4:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_4</Name><USR>c:@F@comment_to_xml_conversion_exceptions_4#</USR><Declaration>void comment_to_xml_conversion_exceptions_4()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para> Bbb. </Para><Para> Ccc. </Para><Para> Ddd.</Para></Exceptions></Function>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_4:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_4</Name><USR>c:@F@comment_to_xml_conversion_exceptions_4#</USR><Declaration>void comment_to_xml_conversion_exceptions_4()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb. </Para><Para>Ccc. </Para><Para>Ddd. </Para></Exceptions></Function>]
 // CHECK-NEXT:  CommentAST=[
 // CHECK-NEXT:    (CXComment_FullComment
 // CHECK-NEXT:       (CXComment_Paragraph
 // CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
 // CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws]
-// CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Bbb.] HasTrailingNewline)
-// CHECK-NEXT:           (CXComment_Text Text=[ ] IsWhitespace)))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws]
-// CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Ccc.] HasTrailingNewline)
-// CHECK-NEXT:           (CXComment_Text Text=[ ] IsWhitespace)))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws]
-// CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Ddd.]))))]
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Bbb.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace))
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Ccc.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace))
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Ddd.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace)))]
 
 /// Aaa.
 /// \throws Bbb.
 /// \throw Ccc.
 void comment_to_xml_conversion_exceptions_5();
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_5:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_5</Name><USR>c:@F@comment_to_xml_conversion_exceptions_5#</USR><Declaration>void comment_to_xml_conversion_exceptions_5()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para> Bbb. </Para><Para> Ccc.</Para></Exceptions></Function>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_5:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_5</Name><USR>c:@F@comment_to_xml_conversion_exceptions_5#</USR><Declaration>void comment_to_xml_conversion_exceptions_5()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb. </Para><Para>Ccc. </Para></Exceptions></Function>]
+// CHECK-NEXT:  CommentAST=[
+// CHECK-NEXT:    (CXComment_FullComment
+// CHECK-NEXT:       (CXComment_Paragraph
+// CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
+// CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Bbb.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace))
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throw] Arg[0]=Ccc.
+// CHECK-NEXT:         (CXComment_Paragraph IsWhitespace)))]
+
+/// Aaa.
+/// \throws Bbb subsequent arg text
+void comment_to_xml_conversion_exceptions_6();
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_6:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_6</Name><USR>c:@F@comment_to_xml_conversion_exceptions_6#</USR><Declaration>void comment_to_xml_conversion_exceptions_6()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb subsequent arg text</Para></Exceptions></Function>]
 // CHECK-NEXT:  CommentAST=[
 // CHECK-NEXT:    (CXComment_FullComment
 // CHECK-NEXT:       (CXComment_Paragraph
 // CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
 // CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws]
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Bbb
 // CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Bbb.] HasTrailingNewline)
+// CHECK-NEXT:           (CXComment_Text Text=[subsequent arg text]))))]
+
+/// Aaa.
+/// \throws Bbb subsequent arg text
+/// \throw Ccc subsequent arg text
+void comment_to_xml_conversion_exceptions_7();
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: FunctionDecl=comment_to_xml_conversion_exceptions_7:{{.*}} FullCommentAsXML=[<Function file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_exceptions_7</Name><USR>c:@F@comment_to_xml_conversion_exceptions_7#</USR><Declaration>void comment_to_xml_conversion_exceptions_7()</Declaration><Abstract><Para> Aaa. </Para></Abstract><Exceptions><Para>Bbb subsequent arg text </Para><Para>Ccc subsequent arg text</Para></Exceptions></Function>]
+// CHECK-NEXT:  CommentAST=[
+// CHECK-NEXT:    (CXComment_FullComment
+// CHECK-NEXT:       (CXComment_Paragraph
+// CHECK-NEXT:         (CXComment_Text Text=[ Aaa.] HasTrailingNewline)
+// CHECK-NEXT:         (CXComment_Text Text=[ ] IsWhitespace))
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throws] Arg[0]=Bbb
+// CHECK-NEXT:         (CXComment_Paragraph
+// CHECK-NEXT:           (CXComment_Text Text=[subsequent arg text] HasTrailingNewline)
 // CHECK-NEXT:           (CXComment_Text Text=[ ] IsWhitespace)))
-// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throw]
+// CHECK-NEXT:       (CXComment_BlockCommand CommandName=[throw] Arg[0]=Ccc
 // CHECK-NEXT:         (CXComment_Paragraph
-// CHECK-NEXT:           (CXComment_Text Text=[ Ccc.]))))]
+// CHECK-NEXT:           (CXComment_Text Text=[subsequent arg text]))))]
 
 #endif
-
diff --git a/clang/unittests/AST/CommentParser.cpp b/clang/unittests/AST/CommentParser.cpp
