Fix after P0600.

gcc/testsuite/ChangeLog
2019-02-20  Ulrich Drepper  <drepper@redhat.com>

	Fix after P0600.
	* g++.dg/init/new39.C: Don't just ignore result of new.

libstdc++/ChangeLog
2019-02-20  Ulrich Drepper  <drepper@redhat.com>

	Implement C++20 P0600r1.
	* include/backward/hash_map: Add nodiscard attribute to empty.
	* include/backward/hash_set: Likewise.
	* backward/hashtable.h: Likewise.
	* include/bits/basic_string.h: Likewise.
	* include/bits/forward_list.h: Likewise.
	* include/bits/hashtable.h: Likewise.
	* include/bits/regex.h: Likewise.
	* include/bits/stl_deque.h: Likewise.
	* include/bits/stl_list.h: Likewise.
	* include/bits/stl_map.h: Likewise.
	* include/bits/stl_multimap.h: Likewise.
	* include/bits/stl_multiset.h: Likewise.
	* include/bits/stl_queue.h: Likewise.
	* include/bits/stl_set.h: Likewise.
	* include/bits/stl_stack.h: Likewise.
	* include/bits/stl_tree.h: Likewise.
	* include/bits/stl_vector.h: Likewise.
	* include/bits/unordered_map.h: Likewise.
	* include/bits/unordered_set.h: Likewise.
	* include/debug/array: Likewise.
	* include/experimental/any: Likewise.
	* include/experimental/bits/fs_path.h: Likewise.
	* include/experimental/internet: Likewise.
	* include/experimental/string_view: Likewise.
	* include/ext/pb_ds/detail/bin_search_tree_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/binary_heap_/binary_heap_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/binary_heap_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/cc_hash_table_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/cc_hash_table_map_/size_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/gp_hash_table_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/left_child_next_sibling_heap_/info_fn_imps.hpp:
	Likewise.
	*
include/ext/pb_ds/detail/left_child_next_sibling_heap_/left_child_next_sibling_heap_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/list_update_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/list_update_map_/lu_map_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/ov_tree_map_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/ov_tree_map_/ov_tree_map_.hp:
	Likewise.
	* include/ext/pb_ds/detail/pat_trie_/info_fn_imps.hpp:
	Likewise.
	* include/ext/pb_ds/detail/pat_trie_/pat_trie_.hpp:
	Likewise.
	* include/ext/pb_ds/detail/rc_binomial_heap_/rc.hpp:
	Likewise.
	* include/ext/pb_ds/detail/tree_trace_base.hpp: Likewise.
	* include/ext/pb_ds/trie_policy.hpp: Likewise.
	* include/ext/rope: Likewise.
	* include/ext/slist: Likewise.
	* include/ext/vstring.h: Likewise.
	* include/profile/array: Likewise.
	* include/std/array: Likewise.
	* include/tr1/array: Likewise.
	* include/tr1/hashtable.h: Likewise.
	* include/tr1/regex: Likewise.
	* include/tr2/dynamic_bitset: Likewise.
	* include/bits/alloc_traits.h: Add nodiscard attribute to
	allocate.
	* include/experimental/memory_resource: Likewise.
	* include/ext/alloc_traits.h: Likewise.
	* include/ext/array_allocator.h: Likewise.
	* include/ext/bitmap_allocator.h: Likewise.
	* include/ext/debug_allocator.h: Likewise.
	* include/ext/extptr_allocator.h: Likewise.
	* include/ext/mt_allocator.h: Likewise.
	* include/ext/new_allocator.h: Likewise.
	* include/ext/pool_allocator.h: Likewise.
	* include/ext/throw_allocator.h: Likewise.
	* include/std/scoped_allocator: Likewise.
	* libsupc++/eh_alloc.cc: Likewise.
	* include/std/future: Add nodiscard attribute to async.
	* libsupc++/new: Add nodiscard attribute to new.

From-SVN: r268111

19 files changed, 21 insertions, 12 deletions

diff --git a/libstdc++-v3/include/ext/pb_ds/detail/bin_search_tree_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/bin_search_tree_/info_fn_imps.hpp
index 5e73955..4019f86 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/bin_search_tree_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/bin_search_tree_/info_fn_imps.hpp
@@ -39,6 +39,7 @@
  */
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/binary_heap_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/binary_heap_.hpp
index 40ddeed5..dbfd612 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/binary_heap_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/binary_heap_.hpp
@@ -144,7 +144,7 @@ namespace __gnu_pbds
 
       ~binary_heap();
 
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       inline size_type
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/info_fn_imps.hpp
index 29612fa..d81d550 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/binary_heap_/info_fn_imps.hpp
@@ -39,6 +39,7 @@
  */
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp
index 6706c1a..1a6affc 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp
@@ -271,7 +271,7 @@ namespace __gnu_pbds
       max_size() const;
 
       /// True if size() == 0.
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       /// Return current hash_fn.
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/info_fn_imps.hpp
index 7b5318b..9d38890 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/info_fn_imps.hpp
@@ -52,6 +52,7 @@ max_size() const
 { return m_entry_allocator.max_size(); }
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/size_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/size_fn_imps.hpp
index 500b92f..bcc1fc4 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/size_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/cc_hash_table_map_/size_fn_imps.hpp
@@ -46,6 +46,7 @@ size() const
 { return m_num_used_e; }
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp
index bcac913..90dfd50 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/gp_ht_map_.hpp
@@ -279,7 +279,7 @@ namespace __gnu_pbds
       max_size() const;
 
       /// True if size() == 0.
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       /// Return current hash_fn.
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/info_fn_imps.hpp
index 64fa975..464216e 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/gp_hash_table_map_/info_fn_imps.hpp
@@ -52,6 +52,7 @@ max_size() const
 { return s_entry_allocator.max_size(); }
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/info_fn_imps.hpp
index 8d31e5b..d12710a 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/info_fn_imps.hpp
@@ -39,6 +39,7 @@
  */
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/left_child_next_sibling_heap_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/left_child_next_sibling_heap_.hpp
index 746a3d8..32d67eb 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/left_child_next_sibling_heap_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/left_child_next_sibling_heap_/left_child_next_sibling_heap_.hpp
@@ -144,7 +144,7 @@ namespace __gnu_pbds
 
       ~left_child_next_sibling_heap();
 
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       inline size_type
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/info_fn_imps.hpp
index 2c44a51..5d2e81f 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/info_fn_imps.hpp
@@ -51,6 +51,7 @@ max_size() const
 { return s_entry_allocator.max_size(); }
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/lu_map_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/lu_map_.hpp
index e3539a5..a3c0fb4 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/lu_map_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/list_update_map_/lu_map_.hpp
@@ -198,7 +198,7 @@ namespace __gnu_pbds
       inline size_type
       max_size() const;
 
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       inline mapped_reference
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/info_fn_imps.hpp
index 26f33bf..81e7305 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/info_fn_imps.hpp
@@ -54,6 +54,7 @@ max_size() const
 { return s_value_alloc.max_size(); }
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/ov_tree_map_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/ov_tree_map_.hpp
index efebc35..0859da1 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/ov_tree_map_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/ov_tree_map_/ov_tree_map_.hpp
@@ -239,7 +239,7 @@ namespace __gnu_pbds
       inline size_type
       max_size() const;
 
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       inline size_type
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/info_fn_imps.hpp b/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/info_fn_imps.hpp
index 0f6eaf5..33fc3e1 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/info_fn_imps.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/info_fn_imps.hpp
@@ -39,6 +39,7 @@
  */
 
 PB_DS_CLASS_T_DEC
+_GLIBCXX_NODISCARD
 inline bool
 PB_DS_CLASS_C_DEC::
 empty() const
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/pat_trie_.hpp b/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/pat_trie_.hpp
index 13da3d4..3f7e054 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/pat_trie_.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/pat_trie_/pat_trie_.hpp
@@ -223,7 +223,7 @@ namespace __gnu_pbds
 	    }
 	}
 
-	inline bool
+	_GLIBCXX_NODISCARD inline bool
 	empty() const
 	{ return m_bag.empty(); }
       };
@@ -279,7 +279,7 @@ namespace __gnu_pbds
 
       ~PB_DS_PAT_TRIE_NAME();
 
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       inline size_type
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/rc_binomial_heap_/rc.hpp b/libstdc++-v3/include/ext/pb_ds/detail/rc_binomial_heap_/rc.hpp
index 2d1b4e7..5c996d1 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/rc_binomial_heap_/rc.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/rc_binomial_heap_/rc.hpp
@@ -87,7 +87,7 @@ namespace __gnu_pbds
       inline void
       pop();
 
-      inline bool
+      _GLIBCXX_NODISCARD inline bool
       empty() const;
 
       inline size_type
@@ -178,7 +178,7 @@ namespace __gnu_pbds
     }
 
     template<typename _Node, typename _Alloc>
-    inline bool
+    _GLIBCXX_NODISCARD inline bool
     rc<_Node, _Alloc>::
     empty() const
     {
diff --git a/libstdc++-v3/include/ext/pb_ds/detail/tree_trace_base.hpp b/libstdc++-v3/include/ext/pb_ds/detail/tree_trace_base.hpp
index 980ff97..3b349c7 100644
--- a/libstdc++-v3/include/ext/pb_ds/detail/tree_trace_base.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/detail/tree_trace_base.hpp
@@ -80,7 +80,7 @@ namespace __gnu_pbds
       void
       trace_node(node_const_iterator, size_type) const;
 
-      virtual bool
+      _GLIBCXX_NODISCARD virtual bool
       empty() const = 0;
 
       virtual node_const_iterator
diff --git a/libstdc++-v3/include/ext/pb_ds/trie_policy.hpp b/libstdc++-v3/include/ext/pb_ds/trie_policy.hpp
index 0b0683d..9c750aa 100644
--- a/libstdc++-v3/include/ext/pb_ds/trie_policy.hpp
+++ b/libstdc++-v3/include/ext/pb_ds/trie_policy.hpp
@@ -315,7 +315,7 @@ namespace __gnu_pbds
     typedef typename __rebind_ma::reference 		metadata_reference;
 
     /// Returns true if the container is empty.
-    virtual bool
+    _GLIBCXX_NODISCARD virtual bool
     empty() const = 0;
 
     /// Returns the iterator associated with the trie's first element.