re PR c++/34950 (ICE in svn boost math toolkit)

        PR c++/34950
        * pt.c (resolve_overloaded_unification): Set processing_template_decl
        while we look for possible bindings.

From-SVN: r132455

gcc/cp/ChangeLog

+2008-02-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/34950
+	* pt.c (resolve_overloaded_unification): Set processing_template_decl
+	while we look for possible bindings.
+
 2008-02-19  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/35028

gcc/cp/pt.c

@@ -12137,6 +12137,7 @@ resolve_overloaded_unification (tree tparms,
 	  if (TREE_CODE (fn) != TEMPLATE_DECL)
 	    continue;
 
+	  ++processing_template_decl;
 	  subargs = get_bindings (fn, DECL_TEMPLATE_RESULT (fn),
 				  expl_subargs, /*check_ret=*/false);
 	  if (subargs)
@@ -12145,6 +12146,7 @@ resolve_overloaded_unification (tree tparms,
 	      good += try_one_overload (tparms, targs, tempargs, parm,
 					elem, strict, sub_strict, addr_p);
 	    }
+	  --processing_template_decl;
 	}
     }
   else if (TREE_CODE (arg) != OVERLOAD

gcc/testsuite/g++.dg/template/explicit-args1.C

+// PR c++/34950
+
+template <class T = int> struct policy {
+    typedef int unnecessary;
+};
+
+template <class Policy> struct A {
+    typedef int type;
+    typedef typename Policy::unnecessary unused;
+};
+
+template <class T> struct S {
+    typedef int type;
+    typedef typename A<T>::type unused;
+};
+
+template <class, class T> typename S<T>::type         foo();
+template <class>                   S<policy<> >::type foo();
+
+template <typename T> int def(T);
+const int i = def(foo<int>);