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C++ PATCH for c++/58466 (ICE with variadics and partial specialization)

Message ID 52E96A65.8090109@redhat.com
State New
Headers show

Commit Message

Jason Merrill Jan. 29, 2014, 8:53 p.m. UTC 
Here the problem was that when we built up A<'X'> the arguments to A 
were 'X' and the empty set for the parameter pack.  When we then use 
that to deduce the arguments for C, we got confused by the empty set and 
tried to treat it as another argument, leading to bad times.  Fixed by 
calling expand_template_argument_pack in unify_pack_expansion.

Tested x86_64-pc-linux-gnu, applying to trunk.
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Patch

commit 8494bec4e85a987375b3e1044574ddb89fa6e120
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Jan 29 15:37:41 2014 -0500

    	PR c++/58466
    	* pt.c (unify_pack_expansion): Call expand_template_argument_pack.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 943255d..9be9171 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16897,6 +16897,9 @@  unify_pack_expansion (tree tparms, tree targs, tree packed_parms,
   tree pattern = PACK_EXPANSION_PATTERN (parm);
   tree pack, packs = NULL_TREE;
   int i, start = TREE_VEC_LENGTH (packed_parms) - 1;
+
+  packed_args = expand_template_argument_pack (packed_args);
+
   int len = TREE_VEC_LENGTH (packed_args);
 
   /* Determine the parameter packs we will be deducing from the
diff --git a/gcc/testsuite/g++.dg/cpp0x/variadic147.C b/gcc/testsuite/g++.dg/cpp0x/variadic147.C
new file mode 100644
index 0000000..7f606d8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic147.C
@@ -0,0 +1,10 @@ 
+// PR c++/58466
+// { dg-require-effective-target c++11 }
+
+template<char, char...> struct A;
+
+template<typename> struct B;
+
+template<char... C> struct B<A<C...>> {};
+
+B<A<'X'>> b;