c++: access of dtor named by qualified template-id [PR100918]

Here, when resolving the destructor named by Inner<int>::~Inner<int>
(which is valid until C++20) we end up in cp_parser_lookup_name called
indirectly from cp_parser_template_id to look up the name Inner from
the scope Inner<int>.  The lookup naturally finds the injected-class-name,
and because the flag is_template is true, we adjust this lookup result
to the TEMPLATE_DECL Inner.  We then check access of this adjusted
lookup result.  But this access check fails because the lookup scope is
Inner<int> and the context_for_name_lookup for the TEMPLATE_DECL is
Outer (whereas for the injected-class-name it's also Inner<int>).

The simplest fix seems to be to check access of the original lookup
result (the injected-class-name) instead of the adjusted result (the
TEMPLATE_DECL).  So this patch moves the access check in
cp_parser_lookup_name to before the injected-class-name adjustment.

	PR c++/100918

gcc/cp/ChangeLog:

	* parser.c (cp_parser_lookup_name): Check access of the lookup
	result before we potentially adjust an injected-class-name to
	its TEMPLATE_DECL.

gcc/testsuite/ChangeLog:

	* g++.dg/template/access38.C: New test.

1 files changed, 13 insertions, 11 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 0649bf9..24f248a 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -29505,6 +29505,19 @@ cp_parser_lookup_name (cp_parser *parser, tree name,
   if (!decl || decl == error_mark_node)
     return error_mark_node;
 
+  /* If we have resolved the name of a member declaration, check to
+     see if the declaration is accessible.  When the name resolves to
+     set of overloaded functions, accessibility is checked when
+     overload resolution is done.  If we have a TREE_LIST, then the lookup
+     is either ambiguous or it found multiple injected-class-names, the
+     accessibility of which is trivially satisfied.
+
+     During an explicit instantiation, access is not checked at all,
+     as per [temp.explicit].  */
+  if (DECL_P (decl))
+    check_accessibility_of_qualified_id (decl, object_type, parser->scope,
+					 tf_warning_or_error);
+
   /* Pull out the template from an injected-class-name (or multiple).  */
   if (is_template)
     decl = maybe_get_template_decl_from_type_decl (decl);
@@ -29531,17 +29544,6 @@ cp_parser_lookup_name (cp_parser *parser, tree name,
 	      || TREE_CODE (decl) == UNBOUND_CLASS_TEMPLATE
 	      || BASELINK_P (decl));
 
-  /* If we have resolved the name of a member declaration, check to
-     see if the declaration is accessible.  When the name resolves to
-     set of overloaded functions, accessibility is checked when
-     overload resolution is done.
-
-     During an explicit instantiation, access is not checked at all,
-     as per [temp.explicit].  */
-  if (DECL_P (decl))
-    check_accessibility_of_qualified_id (decl, object_type, parser->scope,
-					 tf_warning_or_error);
-
   maybe_record_typedef_use (decl);
 
   return cp_expr (decl, name_location);