We had been representing a template non-type parameter as the plain
TEMPLATE_PARM_INDEX in the CLASSTYPE_TI_ARGS of the template, even for a
reference. But when we substitute into that, the reference
automatically decays, so it gets wrapped in an INDIRECT_REF that then
doesn't compare the same as the TEMPLATE_PARM_INDEX by itself. We've
worked around that in tsubst_template_arg by stripping the INDIRECT_REF
again, but tsubst_pack_expansion wasn't doing that. Rather than add the
same code there, I decided to call convert_from_reference when building
the TI_ARGS, so that we don't need any special handling later.
Tested x86_64-pc-linux-gnu, applying to trunk and 4.8.
commit 598166a22b0b94663860c279dd6a51fc8e73eb74
Author: Jason Merrill <ja...@redhat.com>
Date: Mon Jan 27 13:12:05 2014 -0500
PR c++/58606
* pt.c (template_parm_to_arg): Call convert_from_reference.
(tsubst_template_arg): Don't strip reference refs.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4414e49..661143a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -3854,6 +3854,7 @@ template_parm_to_arg (tree t)
SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
(vec, TREE_VEC_LENGTH (vec));
#endif
+ t = convert_from_reference (t);
TREE_VEC_ELT (vec, 0) = make_pack_expansion (t);
t = make_node (NONTYPE_ARGUMENT_PACK);
@@ -9281,10 +9282,6 @@ tsubst_template_arg (tree t, tree args, tsubst_flags_t complain, tree in_decl)
/*integral_constant_expression_p=*/true);
if (!(complain & tf_warning))
--c_inhibit_evaluation_warnings;
- /* Preserve the raw-reference nature of T. */
- if (TREE_TYPE (t) && TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE
- && REFERENCE_REF_P (r))
- r = TREE_OPERAND (r, 0);
}
return r;
}
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic146.C b/gcc/testsuite/g++.dg/cpp0x/variadic146.C
new file mode 100644
index 0000000..0c91db5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic146.C
@@ -0,0 +1,9 @@
+// PR c++/58606
+// { dg-require-effective-target c++11 }
+
+template<int&...I> struct A
+{
+ template<typename> struct B;
+
+ template<typename T> struct B<T*> {};
+};
