diff --git a/kernel/sigtools.h b/kernel/sigtools.h
index 4e97bb775..094d73941 100644
--- a/kernel/sigtools.h
+++ b/kernel/sigtools.h
@@ -138,6 +138,8 @@ struct SigPool
 template <typename T, class Compare = std::less<T>>
 struct SigSet
 {
+	static_assert(!std::is_pointer<T>::value || !std::is_same<Compare, std::less<T>>::value, "Explicit `Compare' class require for SigSet with pointer-type values!");
+
 	struct bitDef_t : public std::pair<RTLIL::Wire*, int> {
 		bitDef_t() : std::pair<RTLIL::Wire*, int>(NULL, 0) { }
 		bitDef_t(const RTLIL::SigBit &bit) : std::pair<RTLIL::Wire*, int>(bit.wire, bit.offset) { }