re PR c++/28058 (ICE in inline_forbidden_p)

	PR c++/28058
	* pt.c (register_specialization): Return error_mark_node for
	specialization-after-instantiation.
	* decl2.c (mark_used): Mark the main function used when one of its
	clones is used.
	
	PR c++/28058
	* g++.dg/template/spec31.C: New test.

From-SVN: r116491

gcc/cp/ChangeLog

+2006-08-27  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/28058
+	* pt.c (register_specialization): Return error_mark_node for
+	specialization-after-instantiation.
+	* decl2.c (mark_used): Mark the main function used when one of its
+	clones is used.
+	
 2006-08-27  Lee Millward  <lee.millward@codesourcery.com>
 
         PR c++/26573

gcc/cp/decl2.c

@@ -3494,6 +3494,8 @@ mark_used (tree decl)
     }
 
   TREE_USED (decl) = 1;
+  if (DECL_CLONED_FUNCTION_P (decl))
+    TREE_USED (DECL_CLONED_FUNCTION (decl)) = 1;
   /* If we don't need a value, then we don't need to synthesize DECL.  */
   if (skip_evaluation)
     return;

gcc/cp/pt.c

@@ -1163,7 +1163,7 @@ register_specialization (tree spec, tree tmpl, tree args, bool is_friend)
 	    {
 	      error ("specialization of %qD after instantiation",
 		     fn);
-	      return spec;
+	      return error_mark_node;
 	    }
 	  else
 	    {

gcc/testsuite/ChangeLog

+2006-08-27  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/28058
+	* g++.dg/template/spec31.C: New test.
+
 2006-08-27  Lee Millward  <lee.millward@codesourcery.com>
 
         PR c++/26573

gcc/testsuite/g++.dg/template/spec31.C

+// PR c++/28058
+
+template<int> struct A
+{
+  A() {}
+};
+
+A<0> a;
+
+template<> A<0>::A() {} // { dg-error "specialization" }