Replace CPP2_TYPEOF to get full type of x

CPP2_TYPEOF revoves cv-qualifiers which matters to matching overloads

Author: filipsajdak

include/cpp2util.h

@@ -1789,13 +1789,13 @@ inline constexpr auto as_( auto&& x ) -> decltype(auto)
 {
     if constexpr (narrowing<C, CPP2_TYPEOF(x)>) {
         static_assert(
-            program_violates_type_safety_guarantee<C, CPP2_TYPEOF(x)>,
+            program_violates_type_safety_guarantee<C, decltype(x)>,
             "'as' does not allow unsafe narrowing conversions - if you're sure you want this, use `unsafe_narrow<T>()` to force the conversion"
         );
     }
     else if constexpr( requires{ { as<C>(CPP2_FORWARD(x)) } -> std::same_as<nonesuch_>; } ) {
         static_assert(
-            program_violates_type_safety_guarantee<C, CPP2_TYPEOF(x)>,
+            program_violates_type_safety_guarantee<C, decltype(x)>,
             "No safe 'as' cast available - please check your cast"
         );
     }
@@ -1808,13 +1808,13 @@ inline constexpr auto as_() -> decltype(auto)
 {
     if constexpr ( !requires { as<C, x>(); }) {
         static_assert(
-            program_violates_type_safety_guarantee<C, CPP2_TYPEOF(x)>,
+            program_violates_type_safety_guarantee<C, decltype(x)>,
             "No safe 'as' cast available - please check your cast"
         );
     }
     if constexpr( requires { {as<C, x>()} -> std::same_as<nonesuch_>; } ) {
         static_assert(
-            program_violates_type_safety_guarantee<C, CPP2_TYPEOF(x)>,
+            program_violates_type_safety_guarantee<C, decltype(x)>,
             "Literal cannot be narrowed using 'as' -  if you're sure you want this, use 'unsafe_narrow<T>()' to force the conversion"
         );
     }