Proposed resolution:

This wording is relative to N5008.

1. Modify [projected] as indicated:

   namespace std {
     template<class I, class Proj>
     struct projected-impl { // exposition only
       struct type { // exposition only
         […]
         // models weakly_incrementable
         indirect_result_t<Proj&, I> operator*() const; // not defined
       };
     };
     […]
   }
   

   indirect_result_t<Proj&, I> operator*() const;
   

   -?- Mandates: This function is not odr-used ([basic.def.odr]).

`std::projected::operator*` is only intentionally used for type calculation like `std::declval`. Currently, if one attempts to call it in a potentially evaluated expression, the program is ill-formed, no diagnostic required because the `operator*` is not defined.

It seems better to diagnose such misuse, as we are already diagnosing misuse of `std::declval` ([declval]/2). Implementation used to perform such misuse via `std::ranges::iter_move`, but libc++ and libstdc++ have already switched not to do this (see microsoft/STL#5555).