From 1b7ac92269bc3ed399572600e1722790c6903f7c Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 7 Jan 2014 16:28:33 -0500
Subject: re PR c++/58856 (spurious 'wrong number of template arguments' error
 for template alias)

	PR c++/58856
	* pt.c (num_innermost_template_parms): New.
	(get_underlying_template): Use it.

From-SVN: r206406
---
 gcc/cp/ChangeLog                           |  4 ++++
 gcc/cp/pt.c                                | 11 +++++++++++
 gcc/testsuite/g++.dg/cpp0x/alias-decl-39.C | 11 +++++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/alias-decl-39.C

(limited to 'gcc')

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index cdb376d..bf2a593 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2014-01-07  Jason Merrill  <jason@redhat.com>
 
+	PR c++/58856
+	* pt.c (num_innermost_template_parms): New.
+	(get_underlying_template): Use it.
+
 	PR c++/58965
 	* mangle.c (write_guarded_var_name): Handle null DECL_NAME.
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 98d7365..2e7cf60 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -5149,6 +5149,15 @@ alias_template_specialization_p (const_tree t)
 	  && DECL_ALIAS_TEMPLATE_P (TYPE_TI_TEMPLATE (t)));
 }
 
+/* Return the number of innermost template parameters in TMPL.  */
+
+static int
+num_innermost_template_parms (tree tmpl)
+{
+  tree parms = INNERMOST_TEMPLATE_PARMS (DECL_TEMPLATE_PARMS (tmpl));
+  return TREE_VEC_LENGTH (parms);
+}
+
 /* Return either TMPL or another template that it is equivalent to under DR
    1286: An alias that just changes the name of a template is equivalent to
    the other template.  */
@@ -5164,6 +5173,8 @@ get_underlying_template (tree tmpl)
 	{
 	  tree sub = TYPE_TI_TEMPLATE (result);
 	  if (PRIMARY_TEMPLATE_P (sub)
+	      && (num_innermost_template_parms (tmpl)
+		  == num_innermost_template_parms (sub))
 	      && same_type_p (result, TREE_TYPE (sub)))
 	    {
 	      /* The alias type is equivalent to the pattern of the
diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-39.C b/gcc/testsuite/g++.dg/cpp0x/alias-decl-39.C
new file mode 100644
index 0000000..9fe5538
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-39.C
@@ -0,0 +1,11 @@
+// PR c++/58856
+// { dg-require-effective-target c++11 }
+
+template <typename T>
+struct U1 {};
+
+template <typename T1, typename... Ts>
+using U2 = U1<T1>;
+
+template <typename T1, typename... Ts>
+using U3 = U2<T1, Ts...>;
-- 
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