+/* Core DR 115: In contexts where deduction is done and fails, or in
+ contexts where deduction is not done, if a template argument list is
+ specified and it, along with any default template arguments, identifies
+ a single function template specialization, then the template-id is an
+ lvalue for the function template specialization. */
+
+tree
+resolve_nondeduced_context (tree orig_expr)
+{
+ tree expr, offset, baselink;
+ bool addr;
+
+ if (!type_unknown_p (orig_expr))
+ return orig_expr;
+
+ expr = orig_expr;
+ addr = false;
+ offset = NULL_TREE;
+ baselink = NULL_TREE;
+
+ if (TREE_CODE (expr) == ADDR_EXPR)
+ {
+ expr = TREE_OPERAND (expr, 0);
+ addr = true;
+ }
+ if (TREE_CODE (expr) == OFFSET_REF)
+ {
+ offset = expr;
+ expr = TREE_OPERAND (expr, 1);
+ }
+ if (TREE_CODE (expr) == BASELINK)
+ {
+ baselink = expr;
+ expr = BASELINK_FUNCTIONS (expr);
+ }
+
+ if (TREE_CODE (expr) == TEMPLATE_ID_EXPR)
+ {
+ int good = 0;
+ tree goodfn = NULL_TREE;
+
+ /* If we got some explicit template args, we need to plug them into
+ the affected templates before we try to unify, in case the
+ explicit args will completely resolve the templates in question. */
+
+ tree expl_subargs = TREE_OPERAND (expr, 1);
+ tree arg = TREE_OPERAND (expr, 0);
+ tree badfn = NULL_TREE;
+ tree badargs = NULL_TREE;
+
+ for (; arg; arg = OVL_NEXT (arg))
+ {
+ tree fn = OVL_CURRENT (arg);
+ tree subargs, elem;
+
+ 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 && !any_dependent_template_arguments_p (subargs))
+ {
+ elem = instantiate_template (fn, subargs, tf_none);
+ if (elem == error_mark_node)
+ {
+ badfn = fn;
+ badargs = subargs;
+ }
+ else if (elem && (!goodfn || !decls_match (goodfn, elem)))
+ {
+ goodfn = elem;
+ ++good;
+ }
+ }
+ --processing_template_decl;
+ }
+ if (good == 1)
+ {
+ expr = goodfn;
+ if (baselink)
+ expr = build_baselink (BASELINK_BINFO (baselink),
+ BASELINK_ACCESS_BINFO (baselink),
+ expr, BASELINK_OPTYPE (baselink));
+ if (offset)
+ expr = build2 (OFFSET_REF, TREE_TYPE (expr),
+ TREE_OPERAND (offset, 0), expr);
+ if (addr)
+ expr = build_address (expr);
+ return expr;
+ }
+ else if (good == 0 && badargs)
+ /* There were no good options and at least one bad one, so let the
+ user know what the problem is. */
+ instantiate_template (badfn, badargs, tf_warning_or_error);
+ }
+ return orig_expr;
+}
+