[Clang] unrecognized html tag causing undesirable comment lexing

clang/docs/ReleaseNotes.rst

@@ -222,6 +222,7 @@ Bug Fixes to AST Handling
 - Fix incorrect name qualifiers applied to alias CTAD. (#GH136624)
 - Fixed ElaboratedTypes appearing within NestedNameSpecifier, which was not a
   legal representation. This is fixed because ElaboratedTypes don't exist anymore. (#GH43179) (#GH68670) (#GH92757)
+- Fix unrecognized html tag causing undesirable comment lexing (#GH152944)
 - Fix comment lexing of special command names (#GH152943)
 
 Miscellaneous Bug Fixes

clang/include/clang/AST/CommentHTMLTags.td

@@ -51,6 +51,11 @@ def Col     : Tag<"col"> { let EndTagForbidden = 1; }
 def Tr      : Tag<"tr"> { let EndTagOptional = 1; }
 def Th      : Tag<"th"> { let EndTagOptional = 1; }
 def Td      : Tag<"td"> { let EndTagOptional = 1; }
+def Summary : Tag<"summary">;
+def Details : Tag<"details">;
+def Mark    : Tag<"mark">;
+def Figure  : Tag<"figure">;
+def FigCaption : Tag<"figcaption">;
 
 // Define a list of attributes that are not safe to pass through to HTML
 // output if the input is untrusted.

clang/test/AST/ast-dump-comment.cpp

@@ -132,6 +132,15 @@ void Test_TemplatedFunctionVariadic(int arg, ...);
 // CHECK-NEXT:     ParagraphComment
 // CHECK-NEXT:       TextComment{{.*}} Text=" More arguments"
 
+/// \param[out] Aaa <summary>Short summary</summary>
+int Test_HTMLSummaryTag(int Aaa);
+// CHECK:     FunctionDecl{{.*}}Test_HTMLSummaryTag
+// CHECK:       ParamCommandComment{{.*}} [out] explicitly Param="Aaa"
+// CHECK-NEXT:    ParagraphComment
+// CHECK:           HTMLStartTagComment{{.*}} Name="summary"
+// CHECK-NEXT:        TextComment{{.*}} Text="Short summary"
+// CHECK-NEXT:        HTMLEndTagComment{{.*}} Name="summary"
+
 /// \thread_safe test for underscore in special command
 int Test_UnderscoreInSpecialCommand;
 // CHECK:      VarDecl{{.*}}Test_UnderscoreInSpecialCommand 'int'