Remove ABI-incompatible assertion code in any_view.hpp (#1816)

* Remove ABI-incompatible assertion code in any_view.hpp

If a provider of an any_view is built without NDEBUG defined, but a
consumer is built with NDEBUG defined, the consumer will crash due to
ABI-incompatibility in any_ref.

Repros on clang with sanitizers, and that's an easily shareable demo:
  https://godbolt.org/z/Go9qxnjrM

Can't get it to repro with a small example in gcc, even with sanitizers

Repros in a small example on windows with msvc using same cpp/hpp files
as above link - usually assertion failure in the assertion that this
commit removes, sometimes Access Violation, but always crashes one way
or another. No sanitizers needed to get a crash with msvc. It's just
not easily shareable.

---------

Co-authored-by: Matt Beardsley <[email protected]>
Co-authored-by: Eric Niebler <[email protected]>

Author: 3 people

include/range/v3/view/any_view.hpp

@@ -128,7 +128,9 @@ namespace ranges
 #ifndef NDEBUG
               , info_(&typeid(rtti_tag<T>))
 #endif
-            {}
+            {
+                (void)info_; // silence unused private member warning
+            }
             template<typename T>
             T & get() const noexcept
             {
@@ -138,9 +140,7 @@ namespace ranges
 
         private:
             void const volatile * obj_ = nullptr;
-#ifndef NDEBUG
             std::type_info const * info_ = nullptr;
-#endif
         };
 
         template<typename Base>