re PR c++/23896 (boost::tie() = std::pair doesn't compile)

	PR c++/23896
	* pt.c (tsubst_aggr_type): Make sure skip_evaluation is false when
	processing template arguments.

	PR c++/23896
	* g++.dg/template/static17.C: New test.

From-SVN: r104336

gcc/cp/ChangeLog

 2005-09-15  Mark Mitchell  <mark@codesourcery.com>
 
+	PR c++/23896
+	* pt.c (tsubst_aggr_type): Make sure skip_evaluation is false when
+	processing template arguments.
+
 	* pt.c (check_explicit_instantiation_namespace): Fix typo.
 
 	PR c++/13140

gcc/cp/pt.c

@@ -6069,6 +6069,11 @@ tsubst_aggr_type (tree t,
 	  tree argvec;
 	  tree context;
 	  tree r;
+	  bool saved_skip_evaluation;
+
+	  /* In "sizeof(X<I>)" we need to evaluate "I".  */
+	  saved_skip_evaluation = skip_evaluation;
+	  skip_evaluation = false;
 
 	  /* First, determine the context for the type we are looking
 	     up.  */
@@ -6089,12 +6094,17 @@ tsubst_aggr_type (tree t,
 	  argvec = tsubst_template_args (TYPE_TI_ARGS (t), args,
 					 complain, in_decl);
 	  if (argvec == error_mark_node)
-	    return error_mark_node;
-
+	    r = error_mark_node;
+	  else
+	    {
 	      r = lookup_template_class (t, argvec, in_decl, context,
 					 entering_scope, complain);
+	      r = cp_build_qualified_type_real (r, TYPE_QUALS (t), complain);
+	    }
 	  
-	  return cp_build_qualified_type_real (r, TYPE_QUALS (t), complain);
+	  skip_evaluation = saved_skip_evaluation;
+
+	  return r;
 	}
       else
 	/* This is not a template type, so there's nothing to do.  */

gcc/testsuite/ChangeLog

+2005-09-15  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23896
+	* g++.dg/template/static17.C: New test.
+
 2005-09-15  Joseph S. Myers  <joseph@codesourcery.com>
 
 	PR c++/23139

gcc/testsuite/g++.dg/template/static17.C

+// PR c++/23896
+
+template <int> struct X {}; 
+ 
+template <typename T> struct length { 
+  static const int value = 2; 
+}; 
+ 
+template <typename T> void foo () { 
+  sizeof(X<length<T>::value>); 
+} 
+ 
+template void foo<int>();