LWG3712 chunk_view and slide_view should not be default_initializable

Author: burblebee

source/ranges.tex

@@ -10919,8 +10919,8 @@
   template<@\libconcept{view}@ V>
     requires @\libconcept{input_range}@<V>
   class chunk_view : public view_interface<chunk_view<V>> {
-    V @\exposid{base_}@ = V();                                        // \expos
-    range_difference_t<V> @\exposid{n_}@ = 0;                         // \expos
+    V @\exposid{base_}@;                                              // \expos
+    range_difference_t<V> @\exposid{n_}@;                             // \expos
     range_difference_t<V> @\exposid{remainder_}@ = 0;                 // \expos
 
     @\exposid{non-propagating-cache}@<iterator_t<V>> @\exposid{current_}@;       // \expos
@@ -10932,7 +10932,6 @@
     class @\exposid{inner-iterator}@;                                 // \expos
 
   public:
-    chunk_view() requires @\libconcept{default_initializable}@<V> = default;
     constexpr explicit chunk_view(V base, range_difference_t<V> n);
 
     constexpr V base() const & requires @\libconcept{copy_constructible}@<V> { return @\exposid{base_}@; }
@@ -11351,14 +11350,13 @@
   template<@\libconcept{view}@ V>
     requires @\libconcept{forward_range}@<V>
   class chunk_view<V> : public view_interface<chunk_view<V>> {
-    V @\exposid{base_}@ = V();                      // \expos
-    range_difference_t<V> @\exposid{n_}@ = 0;       // \expos
+    V @\exposid{base_}@;                            // \expos
+    range_difference_t<V> @\exposid{n_}@;           // \expos
 
     // \ref{range.chunk.fwd.iter}, class template \tcode{chunk_view::\exposid{iterator}}
     template<bool> class @\exposid{iterator}@;      // \expos
 
   public:
-    chunk_view() requires @\libconcept{default_initializable}@<V> = default;
     constexpr explicit chunk_view(V base, range_difference_t<V> n);
 
     constexpr V base() const & requires @\libconcept{copy_constructible}@<V> { return @\exposid{base_}@; }
@@ -11884,8 +11882,8 @@
   template<@\libconcept{forward_range}@ V>
     requires @\libconcept{view}@<V>
   class slide_view : public view_interface<slide_view<V>> {
-    V @\exposid{base_}@ = V();                      // \expos
-    range_difference_t<V> @\exposid{n_}@ = 0;       // \expos
+    V @\exposid{base_}@;                            // \expos
+    range_difference_t<V> @\exposid{n_}@;           // \expos
 
     // \ref{range.slide.iterator}, class template \tcode{slide_view::\exposid{iterator}}
     template<bool> class @\exposid{iterator}@;      // \expos
@@ -11894,7 +11892,6 @@
     class @\exposid{sentinel}@;                     // \expos
 
   public:
-    slide_view() requires @\libconcept{default_initializable}@<V> = default;
     constexpr explicit slide_view(V base, range_difference_t<V> n);
 
     constexpr auto begin()