Hi,
a few days ago I noticed that for, say, g++.dg/parse/qualified2.C we
were issuing two additional misleading errors after the first one,
mentioning in particular a certain "unnamed class" (I'm reproducing only
the error messages proper):
namespace Glib {
template <typename> class Value {};
template <> class Glib::Value<int> {}; // { dg-error "" }
}
qualified2.C:3:29: error: extra qualification not allowed [\-fpermissive\]
qualified2.C:3:46: error: explicit specialization of non-template
‘Glib::<unnamed class>’
qualified2.C:3:47: error: abstract declarator ‘Glib::<unnamed class>’
used as declaration
Let's see if I can explain clearly enough what I think it's going on.
In cp_parser_class_head, upon the permerror about the extra
qualification, we try to do error recovery, which is particularly
tricky, because we are dealing with a permerror thus we have to make
sure that in case of -fpermissive everything remains internally
consistent anyway. In this context, clearing 'nested_name_specifier' and
'num_templates' doesn't seem a good idea because it does *not* give us
an internal state similar to the one normally obtained when the nested
name specifier is not there, the reason being that, earlier in the
function, when a nested name specifier really isn't there we try
cp_parser_template_id or in case cp_parser_identifier, which set the
locale 'id' and possibly 'template_id' and 'num_templates', whereas
during error recovery we remain so to speak completely empty handed.
Thus, what about not clearing anything? That seems to work at least for
the two testcases below and doesn't cause regressions.
Thanks, Paolo.
/////////////////////////////
/cp
2019-10-18 Paolo Carlini <paolo.carl...@oracle.com>
* parser.c (cp_parser_class_head): Improve error recovery upon
extra qualification error.
/testsuite
2019-10-18 Paolo Carlini <paolo.carl...@oracle.com>
* g++.dg/parse/qualified2.C: Tighten dg-error directive.
* g++.old-deja/g++.other/decl5.C: Don't expect redundant error.
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 277149)
+++ cp/parser.c (working copy)
@@ -24178,12 +24178,8 @@ cp_parser_class_head (cp_parser* parser,
... [or] the definition or explicit instantiation of a
class member of a namespace outside of its namespace. */
if (scope == nested_name_specifier)
- {
- permerror (nested_name_specifier_token_start->location,
- "extra qualification not allowed");
- nested_name_specifier = NULL_TREE;
- num_templates = 0;
- }
+ permerror (nested_name_specifier_token_start->location,
+ "extra qualification not allowed");
}
/* An explicit-specialization must be preceded by "template <>". If
it is not, try to recover gracefully. */
Index: testsuite/g++.dg/parse/qualified2.C
===================================================================
--- testsuite/g++.dg/parse/qualified2.C (revision 277144)
+++ testsuite/g++.dg/parse/qualified2.C (working copy)
@@ -1,4 +1,4 @@
namespace Glib {
template <typename> class Value {};
- template <> class Glib::Value<int> {}; // { dg-error "" }
+ template <> class Glib::Value<int> {}; // { dg-error "29:extra
qualification" }
}
Index: testsuite/g++.old-deja/g++.other/decl5.C
===================================================================
--- testsuite/g++.old-deja/g++.other/decl5.C (revision 277144)
+++ testsuite/g++.old-deja/g++.other/decl5.C (working copy)
@@ -12,7 +12,6 @@ struct A {
int A::m; // { dg-error "extra qualification" }
struct e;
struct A::e {int i;}; // { dg-error "extra qualification" "qual" }
- // { dg-error "anonymous struct" "anon" { target *-*-* } .-1 }
struct A::expand { // { dg-error "qualified name" }
int m;
};
