diff --git a/example/measurement.cpp b/example/measurement.cpp
index f517cbaa..935ef345 100644
--- a/example/measurement.cpp
+++ b/example/measurement.cpp
@@ -81,7 +81,7 @@ public:
 #if __GNUC__ >= 10
 
   [[nodiscard]] friend constexpr auto operator<=>(const measurement& lhs, const measurement& rhs) = default;
-  [[nodiscard]] friend constexpr bool operator==(const measurement& lhs, const measurement& rhs) = default;
+  [[nodiscard]] friend constexpr bool operator==(const measurement& lhs, const measurement& rhs) = default; // TODO op== not needed (gcc bug)
 
 #else
 
diff --git a/src/include/units/base_dimension.h b/src/include/units/base_dimension.h
index 5b8d020f..40dbc1bc 100644
--- a/src/include/units/base_dimension.h
+++ b/src/include/units/base_dimension.h
@@ -50,7 +50,7 @@ namespace units {
 template<basic_fixed_string Symbol, Unit U>
   requires U::is_named
 struct base_dimension {
-  using base_type_workaround = base_dimension; // TODO Replace with is_derived_from_instantiation when fixed
+  using base_type_workaround = base_dimension; // TODO Replace with is_base_dimension when fixed
   static constexpr auto symbol = Symbol;
   using base_unit = U;
 };
diff --git a/src/include/units/quantity.h b/src/include/units/quantity.h
index acbc276b..c8789c4e 100644
--- a/src/include/units/quantity.h
+++ b/src/include/units/quantity.h
@@ -220,6 +220,8 @@ public:
     return *this;
   }
 
+  // Hidden Friends
+  // Below friend functions are to be found via argument-dependent lookup only
 #if __GNUC__ >= 10
 
   template<typename D2, typename U2, typename Rep2>
@@ -355,7 +357,7 @@ template<typename D1, typename U1, typename Rep1, typename D2, typename U2, type
 
 template<typename D1, typename U1, typename Rep1, typename D2, typename U2, typename Rep2>
 [[nodiscard]] constexpr Quantity AUTO operator*(const quantity<D1, U1, Rep1>& lhs, const quantity<D2, U2, Rep2>& rhs)
-  requires detail::basic_arithmetic<Rep1, Rep2> && (!equivalent_dim<D1, dim_invert<D2>>)  // TODO equivalent_derived_dim?
+  requires detail::basic_arithmetic<Rep1, Rep2> && (!equivalent_dim<D1, dim_invert<D2>>)
 {
   using dim = dimension_multiply<D1, D2>;
   using ratio1 = ratio_divide<typename U1::ratio, typename dimension_unit<D1>::ratio>;
@@ -405,7 +407,7 @@ template<typename D1, typename U1, typename Rep1, typename D2, typename U2, type
 
 template<typename D1, typename U1, typename Rep1, typename D2, typename U2, typename Rep2>
 [[nodiscard]] constexpr Quantity AUTO operator/(const quantity<D1, U1, Rep1>& lhs, const quantity<D2, U2, Rep2>& rhs)
-  requires detail::basic_arithmetic<Rep1, Rep2> && (!equivalent_dim<D1, D2>)  // TODO equivalent_derived_dim?
+  requires detail::basic_arithmetic<Rep1, Rep2> && (!equivalent_dim<D1, D2>)
 {
   Expects(rhs.count() != 0);
 
diff --git a/src/include/units/unit.h b/src/include/units/unit.h
index 7ce63081..0a4cf121 100644
--- a/src/include/units/unit.h
+++ b/src/include/units/unit.h
@@ -135,10 +135,6 @@ struct named_scaled_unit : downcast_child<Child, scaled_unit<ratio_multiply<R, t
  */
 template<typename Child, Prefix P, Unit U>
   requires std::same_as<typename P::prefix_type, typename U::prefix_type>
-// TODO replace with the below code when gcc will stop to crash on it ;-)
-// struct prefixed_unit : named_scaled_unit<Child, P::symbol + U::symbol, typename P::prefix_type,
-//                                    ratio_multiply<typename P::ratio, typename U::ratio>,
-//                                    typename U::reference> {};
 struct prefixed_unit :
     downcast_child<Child, scaled_unit<ratio_multiply<typename P::ratio, typename U::ratio>, typename U::reference>> {
   static constexpr bool is_named = true;