call.c (build_new_op): Give better error for syntactically correct...

	* call.c (build_new_op): Give better error for syntactically
 	correct, but semantically invalid, use of undeclared template.

From-SVN: r15506

gcc/cp/ChangeLog

 Tue Sep 16 14:06:56 1997  Jason Merrill  <jason@yorick.cygnus.com>
 
+	* call.c (build_new_op): Give better error for syntactically
+ 	correct, but semantically invalid, use of undeclared template.
+
 	* call.c (compare_qual): Handle pmfs.
 
 	* decl.c (store_parm_decls): last_parm_cleanup_insn is the insn

gcc/cp/call.c

@@ -4421,7 +4421,7 @@ build_user_type_conversion_1 (totype, expr, flags)
     (USER_CONV,
      (DECL_CONSTRUCTOR_P (cand->fn)
       ? totype : non_reference (TREE_TYPE (TREE_TYPE (cand->fn)))),
-     NULL_TREE, cand->fn, cand->convs, cand->basetype_path);
+     expr, cand->fn, cand->convs, cand->basetype_path);
   ICS_USER_FLAG (cand->second_conv) = 1;
   if (cand->viable == -1)
     ICS_BAD_FLAG (cand->second_conv) = 1;
@@ -4672,6 +4672,14 @@ build_new_op (code, flags, arg1, arg2, arg3)
       || arg3 == error_mark_node)
     return error_mark_node;
 
+  /* This can happen if a template takes all non-type parameters, e.g.
+     undeclared_template<1, 5, 72>a;  */
+  if (code == LT_EXPR && TREE_CODE (arg1) == TEMPLATE_DECL)
+    {
+      cp_error ("`%D' must be declared before use", arg1);
+      return error_mark_node;
+    }
+
   if (code == MODIFY_EXPR)
     {
       code2 = TREE_CODE (arg3);