LWG4085 ranges::generate_random's helper lambda should specify the return type

Author: burblebee

source/algorithms.tex

@@ -11934,7 +11934,8 @@
 \begin{itemdecl}
 template<class R, class G, class D>
   requires @\libconcept{output_range}@<R, invoke_result_t<D&, G&>> && @\libconcept{invocable}@<D&, G&> &&
-           @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>>
+           @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>> &&
+           is_arithmetic_v<invoke_result_t<D&, G&>>
 constexpr borrowed_iterator_t<R> ranges::generate_random(R&& r, G&& g, D&& d);
 \end{itemdecl}
 
@@ -11983,7 +11984,8 @@
 
 \begin{itemdecl}
 template<class G, class D, @\libconcept{output_iterator}@<invoke_result_t<D&, G&>> O, @\libconcept{sentinel_for}@<O> S>
-  requires @\libconcept{invocable}@<D&, G&> && @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>>
+  requires @\libconcept{invocable}@<D&, G&> && @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>> &&
+           is_arithmetic_v<invoke_result_t<D&, G&>>
 constexpr O ranges::generate_random(O first, S last, G&& g, D&& d);
 \end{itemdecl}
 

source/numerics.tex

@@ -1451,11 +1451,13 @@
 
     template<class R, class G, class D>
       requires @\libconcept{output_range}@<R, invoke_result_t<D&, G&>> && @\libconcept{invocable}@<D&, G&> &&
-               @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>>
+               @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>> &&
+               is_arithmetic_v<invoke_result_t<D&, G&>>
     constexpr borrowed_iterator_t<R> generate_random(R&& r, G&& g, D&& d);
 
     template<class G, class D, @\libconcept{output_iterator}@<invoke_result_t<D&, G&>> O, @\libconcept{sentinel_for}@<O> S>
-      requires @\libconcept{invocable}@<D&, G&> && @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>>
+      requires @\libconcept{invocable}@<D&, G&> && @\libconcept{uniform_random_bit_generator}@<remove_cvref_t<G>> &&
+               is_arithmetic_v<invoke_result_t<D&, G&>>
     constexpr O generate_random(O first, S last, G&& g, D&& d);
   }