re PR c++/92869 (C++17 wrongly reports aggregate type as not-aggregate (when…

re PR c++/92869 (C++17 wrongly reports aggregate type as not-aggregate (when explicitly defaulted ctors are added))

	PR c++/92869
	* class.c (finish_struct): For C++17 and earlier, check
	type_has_user_provided_or_explicit_constructor rather than
	TYPE_HAS_USER_CONSTRUCTOR whether to set CLASSTYPE_NON_AGGREGATE.

	* g++.dg/cpp0x/aggr3.C: New test.

From-SVN: r279241

gcc/cp/ChangeLog

+2019-12-11  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92869
+	* class.c (finish_struct): For C++17 and earlier, check
+	type_has_user_provided_or_explicit_constructor rather than
+	TYPE_HAS_USER_CONSTRUCTOR whether to set CLASSTYPE_NON_AGGREGATE.
+
 2019-12-11  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/92878 - Parenthesized init of aggregates in new-expression.

gcc/cp/class.c

@@ -7474,7 +7474,13 @@ finish_struct (tree t, tree attributes)
       /* Remember current #pragma pack value.  */
       TYPE_PRECISION (t) = maximum_field_alignment;
 
-      if (TYPE_HAS_USER_CONSTRUCTOR (t))
+      if (cxx_dialect < cxx2a)
+	{
+	  if (!CLASSTYPE_NON_AGGREGATE (t)
+	      && type_has_user_provided_or_explicit_constructor (t))
+	    CLASSTYPE_NON_AGGREGATE (t) = 1;
+	}
+      else if (TYPE_HAS_USER_CONSTRUCTOR (t))
 	CLASSTYPE_NON_AGGREGATE (t) = 1;
 
       /* Fix up any variants we've already built.  */

gcc/testsuite/ChangeLog

+2019-12-11  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92869
+	* g++.dg/cpp0x/aggr3.C: New test.
+
 2019-12-11  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/92878 - Parenthesized init of aggregates in new-expression.

gcc/testsuite/g++.dg/cpp0x/aggr3.C

+// PR c++/92869
+// { dg-do compile { target c++11 } }
+
+struct A {
+  A () = default;
+  A (const A &) = default;
+  A (A &&) = default;
+  int arr[3];
+};
+
+template <typename T, int N>
+struct B {
+  B () = default;
+  B (const B &) = default;
+  B (B &&) = default;
+  T arr[N];
+};
+
+A a = { { 1, 2, 3 } };		// { dg-error "could not convert" "" { target c++2a } }
+B<int, 3> b = { { 1, 2, 3 } };	// { dg-error "could not convert" "" { target c++2a } }