[libc++] avoid g++9 Wdeprecated-copy in __hash_table & __tree

[rlibby]

Summary

g++9 now warns if a copy assignment operator is specified and a default
copy constructor is implicitly generated, or vice versa. libc++ tripped
these warnings with some copy assignment operators which were declared
private and not defined. Avoid the warnings by declaring them with
delete.

I should say that I am putting this patch up for comment without having
done all due diligence. I am not an expert here in any case, I don't
have a strong grasp of what's going on here and whether this patch is in
the right direction.

This assumes that the intention of these declarations really had been to
prevent use of the operator=, and that the existing uses of the
implicitly generated default copy constructors are intended and okay.

I have also not yet done useful testing with libcxx. I have however
checked that after applying this patch to the libcxx imported into
FreeBSD, that I no longer see the Wdeprecated-copy warnings upon
building C++ programs with g++9.

[rlibby]

style: tabs->spaces

[EricWF]

Is this change against head? because I thought I already fixed this.

[rlibby]

In D71744#1793660, @EricWF wrote:

Is this change against head? because I thought I already fixed this.

Yes, I believe so. The patch is against 78d6a7767ed57b50122a161b91f59f19c9bd0d19 / trunk@375504 . Is there another branch I should be looking at?

[rlibby]

I was tracking stale source and @EricWF pointed me in the right direction.

include/__hash_table

 
 public:
     typedef typename __alloc_traits::pointer                pointer;
 private:
     typedef __hash_node_types<pointer> _NodeTypes;
 
     allocator_type& __na_;
 
-    __hash_node_destructor& operator=(const __hash_node_destructor&);
+    __hash_node_destructor& operator=(const __hash_node_destructor&)
+        _LIBCPP_EQUAL_DELETE;
 
 public:
     bool __value_constructed;
 
     _LIBCPP_INLINE_VISIBILITY
     explicit __hash_node_destructor(allocator_type& __na,
                                     bool __constructed = false) _NOEXCEPT
         : __na_(__na),

include/__tree

class __tree_node_destructor
     typedef allocator_traits<allocator_type>                __alloc_traits;
 
 public:
     typedef typename __alloc_traits::pointer                pointer;
 private:
     typedef __tree_node_types<pointer> _NodeTypes;
     allocator_type& __na_;
 
-    __tree_node_destructor& operator=(const __tree_node_destructor&);
+    __tree_node_destructor& operator=(const __tree_node_destructor&)
+        _LIBCPP_EQUAL_DELETE;
 
 public:
     bool __value_constructed;
 
     _LIBCPP_INLINE_VISIBILITY
     explicit __tree_node_destructor(allocator_type& __na, bool __val = false) _NOEXCEPT
         : __na_(__na),
           __value_constructed(__val)