diff --git a/codemaker/source/cppumaker/cpputype.cxx b/codemaker/source/cppumaker/cpputype.cxx
index 03fcd033beca..2c8f938e6bb1 100644
--- a/codemaker/source/cppumaker/cpputype.cxx
+++ b/codemaker/source/cppumaker/cpputype.cxx
@@ -1184,7 +1184,7 @@ void InterfaceType::dumpHppFile(
     out << "\n";
     addDefaultHxxIncludes(includes);
     includes.dump(out, &name_, !(m_cppuTypeLeak || m_cppuTypeDynamic));
-    out << "\n";
+    out << "\n#if defined LIBO_INTERNAL_ONLY\n#include <type_traits>\n#endif\n\n";
     dumpGetCppuType(out);
     out << "\n::css::uno::Type const & "
         << codemaker::cpp::scopedCppName(u2b(name_))
@@ -1194,7 +1194,15 @@ void InterfaceType::dumpHppFile(
     dumpType(out, name_, false, false, true);
     out << " >::get();\n";
     dec();
-    out << "}\n\n#endif // "<< headerDefine << "\n";
+    out << "}\n\n#if defined LIBO_INTERNAL_ONLY\nnamespace cppu::detail {\n";
+    if (name_ == "com.sun.star.uno.XInterface") {
+        out << "template<typename> struct IsUnoInterfaceType: ::std::false_type {};\n"
+               "template<typename T> inline constexpr auto isUnoInterfaceType ="
+                   " IsUnoInterfaceType<T>::value;\n";
+    }
+    out << "template<> struct IsUnoInterfaceType<";
+    dumpType(out, name_, false, false, true);
+    out << ">: ::std::true_type {};\n}\n#endif\n\n#endif // "<< headerDefine << "\n";
 }
 
 void InterfaceType::dumpAttributes(FileStream & out) const
diff --git a/include/unotools/weakref.hxx b/include/unotools/weakref.hxx
index 554bd433b687..1d9b29f82e70 100644
--- a/include/unotools/weakref.hxx
+++ b/include/unotools/weakref.hxx
@@ -42,7 +42,9 @@ namespace unotools
     behind it *is* thread-safe, so multiple threads can have their own
     WeakReferences to the same XWeak object.
 
-    @tparam interface_type type of interface
+    @tparam interface_type Must be a C++ implementation class type, not a UNO interface type.  (See
+    the C++20 requires-clause on the get member.  That clause is not put on the class as a whole to
+    avoid overly tight requirements on when interface_type needs to be complete.)
 */
 template <class interface_type>
 class SAL_WARN_UNUSED WeakReference : public com::sun::star::uno::WeakReferenceHelper
@@ -113,6 +115,9 @@ public:
          @return hard reference or null, if the weakly referenced interface has gone
     */
     rtl::Reference<interface_type> SAL_CALL get() const
+#if __cplusplus >= 202002L
+        requires(!cppu::detail::isUnoInterfaceType<interface_type>)
+#endif
     {
         css::uno::Reference<css::uno::XInterface> xInterface = WeakReferenceHelper::get();
         // If XInterface is an ambiguous base of interface_type, we have to use dynamic_cast,