fix

lib/html5_checker/content_model/content_checker.ml

···
   | Content_model.Nothing -> false
   | Content_model.Text -> true
   | Content_model.Transparent -> true (* Inherits parent *)
-  | Content_model.Categories _ -> false (* Elements only *)
+  | Content_model.Categories cats ->
+      (* Phrasing and Flow content include text *)
+      List.mem Content_category.Phrasing cats || List.mem Content_category.Flow cats
   | Content_model.Elements _ -> false (* Specific elements only *)
   | Content_model.Mixed _ -> true (* Text + elements *)
   | Content_model.One_or_more model -> allows_text model
···
 
   match spec_opt with
   | None ->
-      (* Unknown element - emit warning *)
-      Message_collector.add_typed collector
-        (Error_code.Unknown_element { name })
+      (* Unknown element - first check if it's allowed in current context *)
+      validate_child_element state name collector
   | Some spec ->
       (* Check prohibited ancestors *)
       check_prohibited_ancestors state name spec collector;

lib/html5_checker/error_code.ml

···
       (** The "id" attribute on a "map" element must have the same value as the "name" attribute. *)
   | List_attr_requires_datalist
       (** The "list" attribute of "input" must refer to a "datalist" element. *)
+  | Input_list_not_allowed
+      (** Attribute "list" is only allowed on certain input types. *)
   | Label_too_many_labelable
       (** The "label" element may contain at most one labelable descendant. *)
   | Label_for_id_mismatch
···
       (** Element "summary" is missing required attribute "role". *)
   | Summary_missing_attrs
       (** Element "summary" is missing one or more of [aria-checked, aria-level, role]. *)
+  | Summary_role_not_allowed
+      (** The "role" attribute must not be used on any "summary" for its parent "details". *)
   | Autocomplete_webauthn_on_select
       (** The value of "autocomplete" for "select" must not contain "webauthn". *)
   | Commandfor_invalid_target
···
   | Importmap_scopes_values_not_object
       (** The value of "scopes" property values must also be JSON objects. *)
   | Importmap_scopes_invalid_url
-      (** The "scopes" property must only contain valid URL values. *)
+      (** The "scopes" property keys must be valid URL strings. *)
+  | Importmap_scopes_value_invalid_url
+      (** The specifier map within "scopes" must only contain valid URL values. *)
 
   (* ===== Style Element ===== *)
   | Style_type_invalid
···
   | Unnecessary_role _ -> Warning
   | Aria_should_not_be_used _ -> Warning
   | Unknown_element _ -> Warning
+  | Not_nfc _ -> Warning
   | _ -> Error
 
 (** Get a short code string for categorization *)
···
   | Picture_missing_img -> "picture-missing-img"
   | Map_id_name_mismatch -> "map-id-name"
   | List_attr_requires_datalist -> "list-datalist"
+  | Input_list_not_allowed -> "list-not-allowed"
   | Label_too_many_labelable -> "label-multiple"
   | Label_for_id_mismatch -> "label-for-mismatch"
   | Role_on_label_ancestor -> "role-on-label"
···
   | Input_value_constraint _ -> "input-value"
   | Summary_missing_role -> "summary-role"
   | Summary_missing_attrs -> "summary-attrs"
+  | Summary_role_not_allowed -> "summary-role"
   | Autocomplete_webauthn_on_select -> "autocomplete"
   | Commandfor_invalid_target -> "commandfor"
   | Forbidden_codepoint _ -> "forbidden-codepoint"
···
   | Importmap_scopes_not_object -> "importmap"
   | Importmap_scopes_values_not_object -> "importmap"
   | Importmap_scopes_invalid_url -> "importmap"
+  | Importmap_scopes_value_invalid_url -> "importmap"
   | Style_type_invalid -> "style-type"
   | Headingoffset_invalid -> "headingoffset"
   | Media_empty -> "media-empty"
···
   | Bad_attr_value_generic { message } -> message
   | Duplicate_id { id } ->
       Printf.sprintf "Duplicate ID %s." (q id)
-  | Data_attr_invalid_name { reason } -> reason
+  | Data_attr_invalid_name { reason } ->
+      Printf.sprintf "%s attribute names %s." (q "data-*") reason
   | Data_attr_uppercase ->
       Printf.sprintf "%s attributes must not have characters from the range %s\xe2\x80\xa6%s in the name."
         (q "data-*") (q "A") (q "Z")
···
   | List_attr_requires_datalist ->
       Printf.sprintf "The %s attribute of the %s element must refer to a %s element."
         (q "list") (q "input") (q "datalist")
+  | Input_list_not_allowed ->
+      Printf.sprintf "Attribute %s is only allowed when the input type is %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, or %s."
+        (q "list") (q "color") (q "date") (q "datetime-local") (q "email") (q "month")
+        (q "number") (q "range") (q "search") (q "tel") (q "text") (q "time") (q "url") (q "week")
   | Label_too_many_labelable ->
       Printf.sprintf "The %s element may contain at most one %s, %s, %s, %s, %s, %s, or %s descendant."
         (q "label") (q "button") (q "input") (q "meter") (q "output") (q "progress") (q "select") (q "textarea")
···
   | Summary_missing_attrs ->
       Printf.sprintf "Element %s is missing one or more of the following attributes: [aria-checked, aria-level, role]."
         (q "summary")
+  | Summary_role_not_allowed ->
+      Printf.sprintf "The %s attribute must not be used on any %s element that is a summary for its parent %s element."
+        (q "role") (q "summary") (q "details")
   | Autocomplete_webauthn_on_select ->
       Printf.sprintf "The value of the %s attribute for the %s element must not contain %s."
         (q "autocomplete") (q "select") (q "webauthn")
···
       Printf.sprintf "The value of the %s property within the content of a %s element with a %s attribute whose value is %s must be a JSON object whose values are also JSON objects."
         (q "scopes") (q "script") (q "type") (q "importmap")
   | Importmap_scopes_invalid_url ->
+      Printf.sprintf "The value of the %s property within the content of a %s element with a %s attribute whose value is %s must be a JSON object whose keys are valid URL strings."
+        (q "scopes") (q "script") (q "type") (q "importmap")
+  | Importmap_scopes_value_invalid_url ->
       Printf.sprintf "A specifier map defined in a %s property within the content of a %s element with a %s attribute whose value is %s must only contain valid URL values."
         (q "scopes") (q "script") (q "type") (q "importmap")
 

lib/html5_checker/error_code.mli

···
   | Picture_missing_img
   | Map_id_name_mismatch
   | List_attr_requires_datalist
+  | Input_list_not_allowed
   | Label_too_many_labelable
   | Label_for_id_mismatch
   | Role_on_label_ancestor
···
   | Input_value_constraint of { constraint_type: string }
   | Summary_missing_role
   | Summary_missing_attrs
+  | Summary_role_not_allowed
   | Autocomplete_webauthn_on_select
   | Commandfor_invalid_target
 
···
   | Importmap_scopes_not_object
   | Importmap_scopes_values_not_object
   | Importmap_scopes_invalid_url
+  | Importmap_scopes_value_invalid_url
 
   (* Style Element *)
   | Style_type_invalid

lib/html5_checker/specialized/aria_checker.ml

···
       if name_lower = "summary" then begin
         let parent = get_parent_element state in
         let is_in_details = parent = Some "details" in
+        let has_role_attr = List.exists (fun (k, _) -> String.lowercase_ascii k = "role") attrs in
+        let has_aria_expanded = List.assoc_opt "aria-expanded" attrs <> None in
+        let has_aria_pressed = List.assoc_opt "aria-pressed" attrs <> None in
         if is_in_details then begin
           (* summary that is the first child of details *)
-          (* Cannot have role=paragraph (or other non-button roles) *)
-          if explicit_roles <> [] then begin
-            let first_role = List.hd explicit_roles in
-            if first_role <> "button" && first_role <> "none" && first_role <> "presentation" then
-              Message_collector.add_typed collector Error_code.Summary_missing_role
-          end;
+          if has_role_attr then
+            (* Must not have role attribute *)
+            Message_collector.add_typed collector Error_code.Summary_role_not_allowed
+          else if has_aria_pressed then
+            (* aria-pressed without role requires role *)
+            Message_collector.add_typed collector Error_code.Summary_missing_role
+          else if has_aria_expanded then
+            (* aria-expanded without role requires role *)
+            Message_collector.add_typed collector Error_code.Summary_missing_attrs
+        end else begin
+          (* summary NOT in details context - different rules apply *)
           (* If has aria-expanded or aria-pressed, must have role *)
-          let has_aria_expanded = List.assoc_opt "aria-expanded" attrs <> None in
-          let has_aria_pressed = List.assoc_opt "aria-pressed" attrs <> None in
           if (has_aria_expanded || has_aria_pressed) && explicit_roles = [] then begin
             if has_aria_pressed then
               Message_collector.add_typed collector Error_code.Summary_missing_role

lib/html5_checker/specialized/attr_restrictions_checker.ml

···
         | None -> "text"  (* default type is text *)
       in
       if not (List.mem input_type input_types_allowing_list) then
-        Message_collector.add_typed collector Error_code.List_attr_requires_datalist
+        Message_collector.add_typed collector Error_code.Input_list_not_allowed
     end
   end;
 
···
     | Some xmllang ->
       (match lang_value with
        | None ->
+         (* xml:lang without lang attribute *)
          Message_collector.add_typed collector Error_code.Xml_lang_without_lang
        | Some lang when String.lowercase_ascii lang <> String.lowercase_ascii xmllang ->
-         Message_collector.add_typed collector Error_code.Xml_lang_lang_mismatch
+         (* xml:lang and lang have different values - "lang present with same value" message *)
+         Message_collector.add_typed collector Error_code.Xml_lang_without_lang
        | _ -> ())
     | None -> ()
   end;

lib/html5_checker/specialized/importmap_checker.ml

···
   | ForbiddenProperty _ -> Error_code.Importmap_invalid_root
   | SlashKeyWithoutSlashValue _ -> Error_code.Importmap_key_trailing_slash
   | InvalidScopeKey -> Error_code.Importmap_scopes_invalid_url
-  | InvalidScopeValue _ -> Error_code.Importmap_scopes_invalid_url
+  | InvalidScopeValue _ -> Error_code.Importmap_scopes_value_invalid_url
   | ScopeValueNotObject -> Error_code.Importmap_scopes_values_not_object
 
 let end_element state ~name ~namespace collector =