Class template argument deduction in new-expression

	Class template argument deduction in new-expression
	* init.c (build_new): Handle deduction from no initializer.
	* parser.c (cp_parser_new_expression): Don't require a single
	expression for class template deduction.
	* typeck2.c (cxx_incomplete_type_diagnostic): Fix diagnostic for
	class template placeholder.
	* pt.c (tsubst_copy) [TEMPLATE_DECL]: Handle dependent context.
	(tsubst_copy_and_build) [TEMPLATE_ID_EXPR]: Handle SCOPE_REF.
	(redeclare_class_template): Set TEMPLATE_TYPE_PARM_FOR_CLASS.

From-SVN: r245826

1 files changed, 7 insertions, 3 deletions

diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 7ded37e..191fe13 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -3478,15 +3478,19 @@ build_new (vec<tree, va_gc> **placement, tree type, tree nelts,
   if (type == error_mark_node)
     return error_mark_node;
 
-  if (nelts == NULL_TREE && vec_safe_length (*init) == 1
+  if (nelts == NULL_TREE
       /* Don't do auto deduction where it might affect mangling.  */
       && (!processing_template_decl || at_function_scope_p ()))
     {
       tree auto_node = type_uses_auto (type);
       if (auto_node)
 	{
-	  tree d_init = (**init)[0];
-	  d_init = resolve_nondeduced_context (d_init, complain);
+	  tree d_init = NULL_TREE;
+	  if (vec_safe_length (*init) == 1)
+	    {
+	      d_init = (**init)[0];
+	      d_init = resolve_nondeduced_context (d_init, complain);
+	    }
 	  type = do_auto_deduction (type, d_init, auto_node);
 	}
     }