PR libstdc++/85965 move is_invocable assertions again

This is another attempt to reduce how often the assertions are
evaluated, so that code which doesn't try to use the function objects
doesn't need them to be invocable.

For _Rb_tree we access the _M_key_compare object directly, so can't put
the assertions in an accessor function for it. However, every invocation
of _M_key_compare is accompanied by a use of _S_key, so the assertions
can be put in there.  For _Hashtable there are member functions that are
consistently used to obtain a hash code or test for equality, so the
assertions can go in those members.

	PR libstdc++/85965
	* include/bits/hashtable.h (_Hashtable::~_Hashtable()): Remove static
	assertions from the destructor.
	* include/bits/hashtable_policy.h (_Hash_code_base::_M_hash_code):
	Move static_assert for hash function to here.
	(_Hash_table_base::_M_equals): Move static_assert for equality
	predicate to here.
	* include/bits/stl_tree.h (_Rb_tree::_S_value(_Const_Link_type)):
	Remove.
	(_Rb_tree::_S_key(_Const_Link_type)): Move assertions here. Access
	the value directly instead of calling _S_value.
	(_Rb_tree::_S_value(_Const_Base_ptr)): Remove.
	(_Rb_tree::_S_key(_Const_Base_ptr)): Do downcast and forward to
	_S_key(_Const_Link_type).
	* testsuite/23_containers/set/85965.cc: Check construction,
	destruction, assignment and size() do not trigger the assertions.
	* testsuite/23_containers/unordered_set/85965.cc: Likewise.
	* testsuite/23_containers/map/48101_neg.cc: Call find and adjust
	expected errors.
	* testsuite/23_containers/multimap/48101_neg.cc: Likewise.
	* testsuite/23_containers/multiset/48101_neg.cc: Likewise.
	* testsuite/23_containers/set/48101_neg.cc: Likewise.
	* testsuite/23_containers/unordered_map/48101_neg.cc: Likewise.
	* testsuite/23_containers/unordered_multimap/48101_neg.cc: Likewise.
	* testsuite/23_containers/unordered_multiset/48101_neg.cc: Likewise.
	* testsuite/23_containers/unordered_set/48101_neg.cc: Likewise.

From-SVN: r271323

libstdc++-v3/ChangeLog

 2019-05-17  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/85965
+	* include/bits/hashtable.h (_Hashtable::~_Hashtable()): Remove static
+	assertions from the destructor.
+	* include/bits/hashtable_policy.h (_Hash_code_base::_M_hash_code):
+	Move static_assert for hash function to here.
+	(_Hash_table_base::_M_equals): Move static_assert for equality
+	predicate to here.
+	* include/bits/stl_tree.h (_Rb_tree::_S_value(_Const_Link_type)):
+	Remove.
+	(_Rb_tree::_S_key(_Const_Link_type)): Move assertions here. Access
+	the value directly instead of calling _S_value.
+	(_Rb_tree::_S_value(_Const_Base_ptr)): Remove.
+	(_Rb_tree::_S_key(_Const_Base_ptr)): Do downcast and forward to
+	_S_key(_Const_Link_type).
+	* testsuite/23_containers/set/85965.cc: Check construction,
+	destruction, assignment and size() do not trigger the assertions.
+	* testsuite/23_containers/unordered_set/85965.cc: Likewise.
+	* testsuite/23_containers/map/48101_neg.cc: Call find and adjust
+	expected errors.
+	* testsuite/23_containers/multimap/48101_neg.cc: Likewise.
+	* testsuite/23_containers/multiset/48101_neg.cc: Likewise.
+	* testsuite/23_containers/set/48101_neg.cc: Likewise.
+	* testsuite/23_containers/unordered_map/48101_neg.cc: Likewise.
+	* testsuite/23_containers/unordered_multimap/48101_neg.cc: Likewise.
+	* testsuite/23_containers/unordered_multiset/48101_neg.cc: Likewise.
+	* testsuite/23_containers/unordered_set/48101_neg.cc: Likewise.
+
 	* include/bits/invoke.h [__cplusplus < 201703L] (__invoke_r<void>):
 	Use _GLIBCXX14_CONSTEXPR because void functions cannot be constexpr
 	in C++11.

libstdc++-v3/include/bits/hashtable.h

@@ -1351,12 +1351,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       clear();
       _M_deallocate_buckets();
-
-      static_assert(__is_invocable<const _H1&, const _Key&>{},
-	  "hash function must be invocable with an argument of key type");
-      static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
-	  "key equality predicate must be invocable with two arguments of "
-	  "key type");
     }
 
   template<typename _Key, typename _Value,

libstdc++-v3/include/bits/hashtable_policy.h

@@ -1283,7 +1283,11 @@ namespace __detail
 
       __hash_code
       _M_hash_code(const _Key& __k) const
-      { return _M_h1()(__k); }
+      {
+	static_assert(__is_invocable<const _H1&, const _Key&>{},
+	    "hash function must be invocable with an argument of key type");
+	return _M_h1()(__k);
+      }
 
       std::size_t
       _M_bucket_index(const _Key&, __hash_code __c, std::size_t __n) const
@@ -1363,7 +1367,11 @@ namespace __detail
 
       __hash_code
       _M_hash_code(const _Key& __k) const
-      { return _M_h1()(__k); }
+      {
+	static_assert(__is_invocable<const _H1&, const _Key&>{},
+	    "hash function must be invocable with an argument of key type");
+	return _M_h1()(__k);
+      }
 
       std::size_t
       _M_bucket_index(const _Key&, __hash_code __c,
@@ -1783,6 +1791,9 @@ namespace __detail
     bool
     _M_equals(const _Key& __k, __hash_code __c, __node_type* __n) const
     {
+      static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
+	  "key equality predicate must be invocable with two arguments of "
+	  "key type");
       return _Equal_hash_code<__node_type>::_S_equals(__c, *__n)
 	&& _M_eq()(__k, this->_M_extract()(__n->_M_v()));
     }

libstdc++-v3/include/bits/stl_tree.h

@@ -759,13 +759,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_end() const _GLIBCXX_NOEXCEPT
       { return &this->_M_impl._M_header; }
 
-      static const_reference
-      _S_value(_Const_Link_type __x)
-      { return *__x->_M_valptr(); }
-
       static const _Key&
       _S_key(_Const_Link_type __x)
-      { return _KeyOfValue()(_S_value(__x)); }
+      {
+#if __cplusplus >= 201103L
+	// If we're asking for the key we're presumably using the comparison
+	// object, and so this is a good place to sanity check it.
+	static_assert(__is_invocable<_Compare&, const _Key&, const _Key&>{},
+		      "comparison object must be invocable "
+		      "with two arguments of key type");
+# if __cplusplus >= 201703L
+	// _GLIBCXX_RESOLVE_LIB_DEFECTS
+	// 2542. Missing const requirements for associative containers
+	if constexpr (__is_invocable<_Compare&, const _Key&, const _Key&>{})
+	  static_assert(
+	      is_invocable_v<const _Compare&, const _Key&, const _Key&>,
+	      "comparison object must be invocable as const");
+# endif // C++17
+#endif // C++11
+
+	return _KeyOfValue()(*__x->_M_valptr());
+      }
 
       static _Link_type
       _S_left(_Base_ptr __x) _GLIBCXX_NOEXCEPT
@@ -783,13 +797,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _S_right(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT
       { return static_cast<_Const_Link_type>(__x->_M_right); }
 
-      static const_reference
-      _S_value(_Const_Base_ptr __x)
-      { return *static_cast<_Const_Link_type>(__x)->_M_valptr(); }
-
       static const _Key&
       _S_key(_Const_Base_ptr __x)
-      { return _KeyOfValue()(_S_value(__x)); }
+      { return _S_key(static_cast<_Const_Link_type>(__x)); }
 
       static _Base_ptr
       _S_minimum(_Base_ptr __x) _GLIBCXX_NOEXCEPT
@@ -974,21 +984,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
 
       ~_Rb_tree() _GLIBCXX_NOEXCEPT
-      {
-	_M_erase(_M_begin());
-
-#if __cplusplus >= 201103L
-	static_assert(__is_invocable<_Compare&, const _Key&, const _Key&>{},
-		      "comparison object must be invocable "
-		      "with two arguments of key type");
-# if __cplusplus >= 201703L
-      // _GLIBCXX_RESOLVE_LIB_DEFECTS
-      // 2542. Missing const requirements for associative containers
-	static_assert(is_invocable_v<const _Compare&, const _Key&, const _Key&>,
-		      "comparison object must be invocable as const");
-# endif // C++17
-#endif // C++11
-      }
+      { _M_erase(_M_begin()); }
 
       _Rb_tree&
       operator=(const _Rb_tree& __x);

libstdc++-v3/testsuite/23_containers/map/48101_neg.cc

@@ -24,9 +24,13 @@ void
 test01()
 {
   std::map<int, int, std::less<int*>> c;
+  c.find(1);  // { dg-error "here" }
   std::map<int, int, std::allocator<int>> c2;
+  c2.find(2); // { dg-error "here" }
 }
 
 // { dg-error "_Compare = std::less<int.>" "" { target *-*-* } 0 }
 // { dg-error "_Compare = std::allocator<int>" "" { target *-*-* } 0 }
 // { dg-error "comparison object must be invocable" "" { target *-*-* } 0 }
+// { dg-prune-output "no match for call" }
+// { dg-prune-output "invalid conversion" }

libstdc++-v3/testsuite/23_containers/multimap/48101_neg.cc

@@ -24,9 +24,13 @@ void
 test01()
 {
   std::multimap<int, int, std::less<int*>> c;
+  c.find(1);  // { dg-error "here" }
   std::multimap<int, int, std::allocator<int>> c2;
+  c2.find(2); // { dg-error "here" }
 }
 
 // { dg-error "_Compare = std::less<int.>" "" { target *-*-* } 0 }
 // { dg-error "_Compare = std::allocator<int>" "" { target *-*-* } 0 }
 // { dg-error "comparison object must be invocable" "" { target *-*-* } 0 }
+// { dg-prune-output "no match for call" }
+// { dg-prune-output "invalid conversion" }

libstdc++-v3/testsuite/23_containers/multiset/48101_neg.cc

@@ -24,9 +24,12 @@ test01()
 {
   std::multiset<const int> c;		   // { dg-error "here" }
   std::multiset<int, std::less<long*>> c2;
+  c2.find(2);				   // { dg-error "here" }
 }
 
 // { dg-error "non-const, non-volatile value_type" "" { target *-*-* } 0 }
 // { dg-error "comparison object must be invocable" "" { target *-*-* } 0 }
 // { dg-prune-output "std::allocator<.* has no member named " }
 // { dg-prune-output "must have the same value_type as its allocator" }
+// { dg-prune-output "no match for call" }
+// { dg-prune-output "invalid conversion" }

libstdc++-v3/testsuite/23_containers/set/48101_neg.cc

@@ -24,9 +24,12 @@ test01()
 {
   std::set<const int> c;	      // { dg-error "here" }
   std::set<int, std::less<long*>> c2;
+  c2.find(2);				   // { dg-error "here" }
 }
 
 // { dg-error "non-const, non-volatile value_type" "" { target *-*-* } 0 }
 // { dg-error "comparison object must be invocable" "" { target *-*-* } 0 }
 // { dg-prune-output "std::allocator<.* has no member named " }
 // { dg-prune-output "must have the same value_type as its allocator" }
+// { dg-prune-output "no match for call" }
+// { dg-prune-output "invalid conversion" }

libstdc++-v3/testsuite/23_containers/set/85965.cc

@@ -27,3 +27,12 @@ struct Foo
   // PR libstdc++/85965
   std::set<Derived*, std::less<Base*>> s;
 };
+
+std::size_t
+test01(std::set<Derived*, std::less<Base*>> s)
+{
+  // these operations should not require the comparison object
+  auto copy = s;
+  copy = s;
+  return s.size();
+}

libstdc++-v3/testsuite/23_containers/unordered_map/48101_neg.cc

@@ -24,8 +24,10 @@ test01()
 {
   using namespace std;
   unordered_map<int, int, equal_to<int>, hash<int>> c2;
+  c2.find(2); // { dg-error "here" }
 }
 
 // { dg-error "hash function must be invocable" "" { target *-*-* } 0 }
 // { dg-error "key equality predicate must be invocable" "" { target *-*-* } 0 }
 // { dg-prune-output "use of deleted function" }
+// { dg-prune-output "no match for call" }

libstdc++-v3/testsuite/23_containers/unordered_multimap/48101_neg.cc

@@ -24,8 +24,10 @@ test01()
 {
   using namespace std;
   unordered_multimap<int, int, equal_to<int>, hash<int>> c2;
+  c2.find(2); // { dg-error "here" }
 }
 
 // { dg-error "hash function must be invocable" "" { target *-*-* } 0 }
 // { dg-error "key equality predicate must be invocable" "" { target *-*-* } 0 }
 // { dg-prune-output "use of deleted function" }
+// { dg-prune-output "no match for call" }

libstdc++-v3/testsuite/23_containers/unordered_multiset/48101_neg.cc

@@ -25,6 +25,7 @@ test01()
   using namespace std;
   unordered_multiset<const int, hash<int>> c;		// { dg-error "here" }
   unordered_multiset<int, equal_to<int>, hash<int>> c2;
+  c2.find(2);					    // { dg-error "here" }
 }
 
 // { dg-error "non-const, non-volatile value_type" "" { target *-*-* } 0 }
@@ -32,3 +33,4 @@ test01()
 // { dg-error "key equality predicate must be invocable" "" { target *-*-* } 0 }
 // { dg-prune-output "use of deleted function" }
 // { dg-prune-output "must have the same value_type as its allocator" }
+// { dg-prune-output "no match for call" }

libstdc++-v3/testsuite/23_containers/unordered_set/48101_neg.cc

@@ -25,6 +25,7 @@ test01()
   using namespace std;
   unordered_set<const int, hash<int>> c;	    // { dg-error "here" }
   unordered_set<int, equal_to<int>, hash<int>> c2;
+  c2.find(2);					    // { dg-error "here" }
 }
 
 // { dg-error "non-const, non-volatile value_type" "" { target *-*-* } 0 }
@@ -32,3 +33,4 @@ test01()
 // { dg-error "key equality predicate must be invocable" "" { target *-*-* } 0 }
 // { dg-prune-output "use of deleted function" }
 // { dg-prune-output "must have the same value_type as its allocator" }
+// { dg-prune-output "no match for call" }

libstdc++-v3/testsuite/23_containers/unordered_set/85965.cc

@@ -27,3 +27,12 @@ struct Foo
   // PR libstdc++/85965
   std::unordered_set<Derived*, std::equal_to<Base*>, std::hash<Base*>> u;
 };
+
+std::size_t
+test01(std::unordered_set<Derived*, std::equal_to<Base*>, std::hash<Base*>> s)
+{
+  // these operations should not require the comparison object
+  auto copy = s;
+  copy = s;
+  return s.size();
+}