2 files changed, 26 insertions, 2 deletions
diff --git a/absl/flags/flag.h b/absl/flags/flag.h
index 4927757b8fbe..85900ef81b33 100644
--- a/absl/flags/flag.h
+++ b/absl/flags/flag.h
@@ -121,7 +121,7 @@ class Flag {
   bool IsModified() const { return GetImpl()->IsModified(); }
   void SetModified(bool is_modified) { GetImpl()->SetModified(is_modified); }
   bool IsSpecifiedOnCommandLine() const {
-    GetImpl()->IsSpecifiedOnCommandLine();
+    return GetImpl()->IsSpecifiedOnCommandLine();
   }
   absl::string_view Typename() const { return GetImpl()->Typename(); }
   std::string Filename() const { return GetImpl()->Filename(); }
diff --git a/absl/flags/internal/usage.cc b/absl/flags/internal/usage.cc
index 03048514ae0b..181c35c61901 100644
--- a/absl/flags/internal/usage.cc
+++ b/absl/flags/internal/usage.cc
@@ -47,6 +47,27 @@ namespace absl {
 namespace flags_internal {
 namespace {
 
+absl::string_view TypenameForHelp(const flags_internal::CommandLineFlag& flag) {
+  // Only report names of v1 built-in types
+#define HANDLE_V1_BUILTIN_TYPE(t) \
+  if (flag.IsOfType<t>()) {       \
+    return #t;                    \
+  }
+
+  HANDLE_V1_BUILTIN_TYPE(bool);
+  HANDLE_V1_BUILTIN_TYPE(int32_t);
+  HANDLE_V1_BUILTIN_TYPE(int64_t);
+  HANDLE_V1_BUILTIN_TYPE(uint64_t);
+  HANDLE_V1_BUILTIN_TYPE(double);
+#undef HANDLE_V1_BUILTIN_TYPE
+
+  if (flag.IsOfType<std::string>()) {
+    return "string";
+  }
+
+  return "";
+}
+
 // This class is used to emit an XML element with `tag` and `text`.
 // It adds opening and closing tags and escapes special characters in the text.
 // For example:
@@ -186,7 +207,7 @@ void FlagHelpHumanReadable(const flags_internal::CommandLineFlag& flag,
 
   // Flag data type (for V1 flags only).
   if (!flag.IsAbseilFlag() && !flag.IsRetired()) {
-    printer.Write(absl::StrCat("type: ", flag.Typename(), ";"));
+    printer.Write(absl::StrCat("type: ", TypenameForHelp(flag), ";"));
   }
 
   // The listed default value will be the actual default from the flag
@@ -223,6 +244,9 @@ void FlagsHelpImpl(std::ostream& out, flags_internal::FlagKindFilter filter_cb,
   } else {
     // XML schema is not a part of our public API for now.
     out << "<?xml version=\"1.0\"?>\n"
+        << "<!-- This output should be used with care. We do not report type "
+           "names for flags with user defined types -->\n"
+        << "<!-- Prefer flag only_check_args for validating flag inputs -->\n"
         // The document.
         << "<AllFlags>\n"
         // The program name and usage.