diff --git a/example/include/geographic.h b/example/include/geographic.h
index 2eae3e50..b3268393 100644
--- a/example/include/geographic.h
+++ b/example/include/geographic.h
@@ -92,29 +92,38 @@ std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>&
 
 inline namespace literals {
 
-constexpr latitude<long double> operator"" _N(long double v) { return v * mp_units::si::degree; }
-constexpr latitude<long double> operator"" _S(long double v) { return -v * mp_units::si::degree; }
-constexpr longitude<long double> operator"" _E(long double v) { return v * mp_units::si::degree; }
-constexpr longitude<long double> operator"" _W(long double v) { return -v * mp_units::si::degree; }
+constexpr latitude<long double> operator"" _N(long double v) { return latitude<long double>{v * mp_units::si::degree}; }
+constexpr latitude<long double> operator"" _S(long double v)
+{
+  return latitude<long double>{-v * mp_units::si::degree};
+}
+constexpr longitude<long double> operator"" _E(long double v)
+{
+  return longitude<long double>{v * mp_units::si::degree};
+}
+constexpr longitude<long double> operator"" _W(long double v)
+{
+  return longitude<long double>{-v * mp_units::si::degree};
+}
 constexpr latitude<std::int64_t> operator"" _N(unsigned long long v)
 {
   gsl_ExpectsAudit(std::in_range<std::int64_t>(v));
-  return static_cast<std::int64_t>(v) * mp_units::si::degree;
+  return latitude<std::int64_t>{static_cast<std::int64_t>(v) * mp_units::si::degree};
 }
 constexpr latitude<std::int64_t> operator"" _S(unsigned long long v)
 {
   gsl_ExpectsAudit(std::in_range<std::int64_t>(v));
-  return -static_cast<std::int64_t>(v) * mp_units::si::degree;
+  return latitude<std::int64_t>{-static_cast<std::int64_t>(v) * mp_units::si::degree};
 }
 constexpr longitude<std::int64_t> operator"" _E(unsigned long long v)
 {
   gsl_ExpectsAudit(std::in_range<std::int64_t>(v));
-  return static_cast<std::int64_t>(v) * mp_units::si::degree;
+  return longitude<std::int64_t>{static_cast<std::int64_t>(v) * mp_units::si::degree};
 }
 constexpr longitude<std::int64_t> operator"" _W(unsigned long long v)
 {
   gsl_ExpectsAudit(std::in_range<std::int64_t>(v));
-  return -static_cast<std::int64_t>(v) * mp_units::si::degree;
+  return longitude<std::int64_t>{-static_cast<std::int64_t>(v) * mp_units::si::degree};
 }
 
 }  // namespace literals
diff --git a/src/core/include/mp_units/quantity.h b/src/core/include/mp_units/quantity.h
index fd719de4..4862870e 100644
--- a/src/core/include/mp_units/quantity.h
+++ b/src/core/include/mp_units/quantity.h
@@ -138,7 +138,8 @@ public:
   quantity(quantity&&) = default;
 
   template<detail::QuantityConvertibleTo<quantity> Q>
-  constexpr explicit(false) quantity(const Q& q) : number_(detail::sudo_cast<quantity>(q).number())
+  constexpr explicit(!std::convertible_to<typename Q::rep, Rep>) quantity(const Q& q) :
+      number_(detail::sudo_cast<quantity>(q).number())
   {
   }