re PR c++/22137 (Internal error: Segmentation fault (program cc1plus))

[thirdparty/gcc.git] / gcc / cp / typeck.c

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index d39b53ae967b2c1583979446bd8a644db94cbc7e..bc34a40380688146fb6730af72961eaeda890c8f 100644 (file)
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -1841,16 +1841,69 @@ lookup_destructor (tree object, tree scope, tree dtor_name)
   return expr;
 }
 
+/* An expression of the form "A::template B" has been resolved to
+   DECL.  Issue a diagnostic if B is not a template or template
+   specialization.  */
+
+void
+check_template_keyword (tree decl)
+{
+  /* The standard says:
+
+      [temp.names]
+
+      If a name prefixed by the keyword template is not a member
+      template, the program is ill-formed.
+
+     DR 228 removed the restriction that the template be a member
+     template.  
+     
+     DR 96, if accepted would add the further restriction that explcit
+     template arguments must be provided if the template keyword is
+     used, but, as of 2005-10-16, that DR is still in "drafting".  If
+     this DR is accepted, then the semantic checks here can be
+     simplified, as the entity named must in fact be a template
+     specialization, rather than, as at present, a set of overloaded
+     functions containing at least one template function.  */
+  if (TREE_CODE (decl) != TEMPLATE_DECL
+      && TREE_CODE (decl) != TEMPLATE_ID_EXPR)
+    {
+      if (!is_overloaded_fn (decl))
+       pedwarn ("%qD is not a template", decl);
+      else
+       {
+         tree fns;
+         if (BASELINK_P (decl))
+           fns = BASELINK_FUNCTIONS (decl);
+         while (fns)
+           {
+             tree fn = OVL_CURRENT (fns);
+             if (TREE_CODE (fn) == TEMPLATE_DECL
+                 || TREE_CODE (fn) == TEMPLATE_ID_EXPR)
+               break;
+             if (TREE_CODE (fn) == FUNCTION_DECL
+                 && DECL_USE_TEMPLATE (fn)
+                 && PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (fn)))
+               break;
+             fns = OVL_NEXT (fns);
+           }
+         if (!fns)
+           pedwarn ("%qD is not a template", decl);
+       }
+    }
+}
+
 /* This function is called by the parser to process a class member
    access expression of the form OBJECT.NAME.  NAME is a node used by
    the parser to represent a name; it is not yet a DECL.  It may,
    however, be a BASELINK where the BASELINK_FUNCTIONS is a
    TEMPLATE_ID_EXPR.  Templates must be looked up by the parser, and
    there is no reason to do the lookup twice, so the parser keeps the
-   BASELINK.  */
+   BASELINK.  TEMPLATE_P is true iff NAME was explicitly declared to
+   be a template via the use of the "A::template B" syntax.  */
 
 tree
-finish_class_member_access_expr (tree object, tree name)
+finish_class_member_access_expr (tree object, tree name, bool template_p)
 {
   tree expr;
   tree object_type;
@@ -1995,6 +2048,9 @@ finish_class_member_access_expr (tree object, tree name)
   if (TREE_DEPRECATED (member))
     warn_deprecated_use (member);
 
+  if (template_p)
+    check_template_keyword (member);
+
   expr = build_class_member_access_expr (object, member, access_path,
                                         /*preserve_reference=*/false);
   if (processing_template_decl && expr != error_mark_node)