On Mon, Feb 28, 2022 at 12:31:37PM -0400, Jason Merrill wrote:
> On 2/22/22 17:46, Marek Polacek wrote:
> > Here we have a forward declaration of Parameter for which we create
> > an implicit typedef, which is a TYPE_DECL. Then, when looking it up
> > at template definition time, cp_parser_template_id gets (since r12-6754)
> > this TYPE_DECL which it can't handle.
>
> Hmm, getting that global TYPE_DECL from lookup seems like a bug; isn't the
> lookup earlier in cp_parser_template_name in object scope?
Yes, it is (in Function), but I think we do the pre-DR1835 lookup. For
this->template Parameter<R>();
we don't find Parameter in the object expression's type (Function), so we do
unqualified lookup in the enclosing context and find the global Parameter
TYPE_DECL. This is implemented in cp_parser_lookup_name:
decl = lookup_member (object_type, name, ...);
if (!decl)
decl = lookup_name (name, ...);
[basic.lookup.qual.general] now says that we only perform unqualified lookup
if the object type isn't dependent. But I don't think we can fix this by
implementing DR1835 because that would only help in C++23(?).
My v1 patch is wrong in any case; I've come up with template-keyword4.C
where we find a TYPE_DECL which is not an implicit typedef.
Since cp_parser_template_id is only able to handle these TYPE_DECLs:
18353 else if (TREE_CODE (templ) == TYPE_DECL
18354 && TREE_CODE (TREE_TYPE (templ)) == TYPENAME_TYPE)
this v2 patch fixes the problem by repeating lookup of TYPE_DECLs whose
TREE_TYPE is *not* TYPENAME_TYPE. That fixes my testcases and doesn't
regress any.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Here we have a forward declaration of Parameter for which we create
an implicit typedef, which is a TYPE_DECL. Then, when looking it up
at template definition time, cp_parser_template_id gets (since r12-6754)
this TYPE_DECL which it can't handle.
This patch defers lookup for TYPE_DECLs that cp_parser_template_id can't
handle, a la r12-6879.
PR c++/104608
gcc/cp/ChangeLog:
* parser.cc (cp_parser_template_name): Repeat lookup of
TYPE_DECLs.
gcc/testsuite/ChangeLog:
* g++.dg/parse/template-keyword3.C: New test.
* g++.dg/parse/template-keyword4.C: New test.
---
gcc/cp/parser.cc | 5 ++++-
gcc/testsuite/g++.dg/parse/template-keyword3.C | 12 ++++++++++++
gcc/testsuite/g++.dg/parse/template-keyword4.C | 17 +++++++++++++++++
3 files changed, 33 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/parse/template-keyword3.C
create mode 100644 gcc/testsuite/g++.dg/parse/template-keyword4.C
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 03d99aba13e..02c34bf964e 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -18681,7 +18681,10 @@ cp_parser_template_name (cp_parser* parser,
return error_mark_node;
}
else if ((!DECL_P (decl) && !is_overloaded_fn (decl))
- || TREE_CODE (decl) == USING_DECL)
+ || TREE_CODE (decl) == USING_DECL
+ /* cp_parser_template_id can only handle some TYPE_DECLs. */
+ || (TREE_CODE (decl) == TYPE_DECL
+ && TREE_CODE (TREE_TYPE (decl)) != TYPENAME_TYPE))
/* Repeat the lookup at instantiation time. */
decl = identifier;
}
diff --git a/gcc/testsuite/g++.dg/parse/template-keyword3.C
b/gcc/testsuite/g++.dg/parse/template-keyword3.C
new file mode 100644
index 00000000000..59fe0fc180b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/template-keyword3.C
@@ -0,0 +1,12 @@
+// PR c++/104608
+
+class Parameter;
+template <typename R> class Function
+: public R
+{
+ Function();
+};
+template <typename R>
+Function<R>::Function() {
+ this->template Parameter<R>();
+}
diff --git a/gcc/testsuite/g++.dg/parse/template-keyword4.C
b/gcc/testsuite/g++.dg/parse/template-keyword4.C
new file mode 100644
index 00000000000..c688094bcf2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/template-keyword4.C
@@ -0,0 +1,17 @@
+// PR c++/104608
+// { dg-do compile { target c++11 } }
+
+class S;
+using Parameter = S;
+typedef S Parameter2;
+
+template <typename R> class Function
+: public R
+{
+ Function();
+};
+template <typename R>
+Function<R>::Function() {
+ this->template Parameter<R>();
+ this->template Parameter2<R>();
+}
base-commit: 4a1c20df82c9e14478d79fbe1ae9690a36285ac1
--
2.35.1
