PR c++/88136 - -Wdeprecated-copy false positives

Deprecating the copy operations because the class has a user-provided
destructor turns out to have too many false positives; this patch adjusts
-Wdeprecated-copy to only deprecate if the other copy operation is
user-provided.  To get the earlier behavior, people can explicitly request
it with -Wdeprecated-copy-dtor.

gcc/c-family/
	* c.opt (Wdeprecated-copy-dtor): New.
	(Wdeprecated-copy): Move to -Wextra.
gcc/cp/
	* class.c (classtype_has_depr_implicit_copy): Rename from
	classtype_has_user_copy_or_dtor.
	* method.c (lazily_declare_fn): Adjust.
	* decl2.c (cp_warn_deprecated_use): Refer to -Wdeprecated-copy-dtor
	if deprecation is due to a destructor.

From-SVN: r266867

5 files changed, 27 insertions, 13 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 1a3e73e..601ca78a 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,12 @@
+2018-12-06  Jason Merrill  <jason@redhat.com>
+
+	PR c++/88136 - -Wdeprecated-copy false positives
+	* class.c (classtype_has_depr_implicit_copy): Rename from
+	classtype_has_user_copy_or_dtor.
+	* method.c (lazily_declare_fn): Adjust.
+	* decl2.c (cp_warn_deprecated_use): Refer to -Wdeprecated-copy-dtor
+	if deprecation is due to a destructor.
+
 2018-12-06  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/88373 - wrong parse error with ~.
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 5726151..9c175f8 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -5233,7 +5233,7 @@ classtype_has_non_deleted_move_ctor (tree t)
    operator, or destructor, returns that function.  Otherwise, null.  */
 
 tree
-classtype_has_user_copy_or_dtor (tree t)
+classtype_has_depr_implicit_copy (tree t)
 {
   if (!CLASSTYPE_LAZY_COPY_CTOR (t))
     for (ovl_iterator iter (CLASSTYPE_CONSTRUCTORS (t)); iter; ++iter)
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 636e53a..3645965 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6273,7 +6273,7 @@ extern bool type_has_constexpr_default_constructor (tree);
 extern bool type_has_virtual_destructor		(tree);
 extern bool classtype_has_move_assign_or_move_ctor_p (tree, bool user_declared);
 extern bool classtype_has_non_deleted_move_ctor (tree);
-extern tree classtype_has_user_copy_or_dtor	(tree);
+extern tree classtype_has_depr_implicit_copy	(tree);
 extern bool type_build_ctor_call		(tree);
 extern bool type_build_dtor_call		(tree);
 extern void explain_non_literal_class		(tree);
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index f996a27..15b0393 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -5298,18 +5298,23 @@ cp_warn_deprecated_use (tree decl, tsubst_flags_t complain)
       && DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)
       && copy_fn_p (decl))
     {
-      auto_diagnostic_group d;
-      /* Don't warn about system library classes (c++/86342).  */
-      if (!DECL_IN_SYSTEM_HEADER (decl))
-	warned = warning (OPT_Wdeprecated_copy,
-			  "implicitly-declared %qD is deprecated", decl);
-      if (warned)
+      if (warn_deprecated_copy
+	  /* Don't warn about system library classes (c++/86342).  */
+	  && (!DECL_IN_SYSTEM_HEADER (decl)
+	      || global_dc->dc_warn_system_headers))
 	{
+	  auto_diagnostic_group d;
 	  tree ctx = DECL_CONTEXT (decl);
-	  tree other = classtype_has_user_copy_or_dtor (ctx);
-	  inform (DECL_SOURCE_LOCATION (other),
-		  "because %qT has user-provided %qD",
-		  ctx, other);
+	  tree other = classtype_has_depr_implicit_copy (ctx);
+	  int opt = (DECL_DESTRUCTOR_P (other)
+		     ? OPT_Wdeprecated_copy_dtor
+		     : OPT_Wdeprecated_copy);
+	  warned = warning (opt, "implicitly-declared %qD is deprecated",
+			    decl);
+	  if (warned)
+	    inform (DECL_SOURCE_LOCATION (other),
+		    "because %qT has user-provided %qD",
+		    ctx, other);
 	}
     }
   else
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 936dad4..fd023e2 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -2380,7 +2380,7 @@ lazily_declare_fn (special_function_kind sfk, tree type)
     {
       if (classtype_has_move_assign_or_move_ctor_p (type, true))
 	DECL_DELETED_FN (fn) = true;
-      else if (classtype_has_user_copy_or_dtor (type))
+      else if (classtype_has_depr_implicit_copy (type))
 	/* The implicit definition of a copy constructor as defaulted is
 	   deprecated if the class has a user-declared copy assignment operator
 	   or a user-declared destructor. The implicit definition of a copy