PR c++/71837 - pack expansion in init-capture

	* lambda.c (add_capture): Leave a pack expansion in a TREE_LIST.
	(build_lambda_object): Call build_x_compound_expr_from_list.
	* pt.c (tsubst) [DECLTYPE_TYPE]: Likewise.

From-SVN: r238733

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9ae7e67eb21902876b4e5729880f692396f819c0..87020979510d8b2d816ec8847aab3f7adb029f44 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,10 @@
 2016-07-25  Jason Merrill  <jason@redhat.com>
 
+       PR c++/71837
+       * lambda.c (add_capture): Leave a pack expansion in a TREE_LIST.
+       (build_lambda_object): Call build_x_compound_expr_from_list.
+       * pt.c (tsubst) [DECLTYPE_TYPE]: Likewise.
+
        PR c++/71833
        PR c++/54440
        * pt.c (coerce_template_parameter_pack): Fix logic for

diff --git a/gcc/cp/lambda.c b/gcc/cp/lambda.c
index 4d6d80fe128ddb6b95285f598a40f0fa2b738b58..9bf8a560d020be028160d9039623848272550023 100644 (file)
--- a/gcc/cp/lambda.c
+++ b/gcc/cp/lambda.c
@@ -79,6 +79,10 @@ build_lambda_object (tree lambda_expr)
          goto out;
        }
 
+      if (TREE_CODE (val) == TREE_LIST)
+       val = build_x_compound_expr_from_list (val, ELK_INIT,
+                                              tf_warning_or_error);
+
       if (DECL_P (val))
        mark_used (val);
 
@@ -449,7 +453,9 @@ add_capture (tree lambda, tree id, tree orig_init, bool by_reference_p,
       variadic = true;
     }
 
-  if (TREE_CODE (initializer) == TREE_LIST)
+  if (TREE_CODE (initializer) == TREE_LIST
+      /* A pack expansion might end up with multiple elements.  */
+      && !PACK_EXPANSION_P (TREE_VALUE (initializer)))
     initializer = build_x_compound_expr_from_list (initializer, ELK_INIT,
                                                   tf_warning_or_error);
   type = TREE_TYPE (initializer);

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 7dd6b25931d6ffad92e15deaf3b92abac22c4595..97d50001b146b211b9f287312571eb8f557c3650 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -13620,6 +13620,18 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
                                      /*function_p*/false,
                                      /*integral_constant_expression*/false);
 
+       if (DECLTYPE_FOR_INIT_CAPTURE (t))
+         {
+           if (type == NULL_TREE)
+             {
+               if (complain & tf_error)
+                 error ("empty initializer in lambda init-capture");
+               type = error_mark_node;
+             }
+           else if (TREE_CODE (type) == TREE_LIST)
+             type = build_x_compound_expr_from_list (type, ELK_INIT, complain);
+         }
+
        --cp_unevaluated_operand;
        --c_inhibit_evaluation_warnings;
 

diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init15.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init15.C
new file mode 100644 (file)
index 0000000..8b3e520
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init15.C
@@ -0,0 +1,13 @@
+// PR c++/71837
+// { dg-do compile { target c++14 } }
+
+template < typename ... Ts > void f (Ts ... args)
+{
+  [ts (args ...)] { return ts; } ();
+}
+
+int main ()
+{ 
+  f (0);
+  return 0;
+}

diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init15a.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init15a.C
new file mode 100644 (file)
index 0000000..166d650
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init15a.C
@@ -0,0 +1,14 @@
+// PR c++/71837
+// { dg-do compile { target c++14 } }
+
+template < typename ... Ts > void f (Ts ... args)
+{
+  [ts (args ...)] { return ts; } (); // { dg-error "" }
+}
+
+int main ()
+{ 
+  f ();                                // { dg-message "required" }
+  f (1,2);                     // { dg-message "required" }
+  return 0;
+}