Hi Jason,
On 22 Aug 2024, at 19:28, Jason Merrill wrote:
> On 8/22/24 12:51 PM, Simon Martin wrote:
>> We currently ICE upon the following invalid code, because we don't
>> check the
>> number of template parameters in member class template
>> specializations. This
>> patch fixes the PR by adding such a check.
>>
>> === cut here ===
>> template <typename T> struct x {
>> template <typename U> struct y {
>> typedef T result2;
>> };
>> };
>> template<> template<typename U, typename> struct x<int>::y {
>> typedef double result2;
>> };
>> int main() {
>> x<int>::y<int>::result2 xxx2;
>> }
>> === cut here ===
>>
>> Successfully tested on x86_64-pc-linux-gnu.
>>
>> PR c++/115716
>>
>> gcc/cp/ChangeLog:
>>
>> * pt.cc (maybe_process_partial_specialization): Check number of
>> template parameters in specialization.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * g++.dg/template/spec42.C: New test.
>>
>> ---
>> gcc/cp/pt.cc | 14 ++++++++++++++
>> gcc/testsuite/g++.dg/template/spec42.C | 17 +++++++++++++++++
>> 2 files changed, 31 insertions(+)
>> create mode 100644 gcc/testsuite/g++.dg/template/spec42.C
>>
>> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
>> index bc3ad5edcc5..db8c2a3b4de 100644
>> --- a/gcc/cp/pt.cc
>> +++ b/gcc/cp/pt.cc
>> @@ -1173,6 +1173,20 @@ maybe_process_partial_specialization (tree
>> type)
>> type, inst);
>> }
>> + /* Check that the number of template parameters matches the
>> template
>> + being specialized. */
>> + gcc_assert (current_template_parms);
>> + if (TREE_VEC_LENGTH (INNERMOST_TEMPLATE_ARGS
>> + (CLASSTYPE_TI_ARGS (type)))
>> + != TREE_VEC_LENGTH (INNERMOST_TEMPLATE_PARMS
>> + (current_template_parms)))
>> + {
>> + error ("wrong number of template parameters for %qT", type);
>> + inform (DECL_SOURCE_LOCATION (tmpl), "from definition of
>> %q#D",
>> + tmpl);
>
> How about printing the numbers for each place?
>
> What if the mismatch is other than in the number of parameters? Can
> you use template_parameter_lists_equivalent_p? Or if that's
> complicated, compare current_template_args() to CLASSTYPE_TI_ARGS
> (type)?
>
Thanks for the review. After checking further, I believe we just miss a
call to redeclare_class_template, that will catch various template
parameter mismatch and properly report them.
This is what the updated attached patch does, successfully tested on
x86_64-pc-linux-gnu. OK for trunk?
Thanks,
Simon
> Jason
From 7e817c158e7d2e83e0283c3fa892370dbf9a238a Mon Sep 17 00:00:00 2001
From: Simon Martin <si...@nasilyan.com>
Date: Sun, 25 Aug 2024 21:59:31 +0200
Subject: [PATCH] c++: Check template parameters in member class template
specialization [PR115716]
We currently ICE upon the following invalid code, because we don't check
that the template parameters in a member class template specialization
are correct.
=== cut here ===
template <typename T> struct x {
template <typename U> struct y {
typedef T result2;
};
};
template<> template<typename U, typename> struct x<int>::y {
typedef double result2;
};
int main() {
x<int>::y<int>::result2 xxx2;
}
=== cut here ===
This patch fixes the PR by calling redeclare_class_template.
Successfully tested on x86_64-pc-linux-gnu.
PR c++/115716
gcc/cp/ChangeLog:
* pt.cc (maybe_process_partial_specialization): Call
redeclare_class_template.
gcc/testsuite/ChangeLog:
* g++.dg/template/spec42.C: New test.
* g++.dg/template/spec43.C: New test.
---
gcc/cp/pt.cc | 5 +++++
gcc/testsuite/g++.dg/template/spec42.C | 17 +++++++++++++++++
gcc/testsuite/g++.dg/template/spec43.C | 18 ++++++++++++++++++
3 files changed, 40 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/template/spec42.C
create mode 100644 gcc/testsuite/g++.dg/template/spec43.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index bc3ad5edcc5..24a6241d3a5 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -1173,6 +1173,11 @@ maybe_process_partial_specialization (tree type)
type, inst);
}
+ /* Make sure that the specialization is valid. */
+ if (!redeclare_class_template (type, current_template_parms,
+ current_template_constraints ()))
+ return error_mark_node;
+
/* Mark TYPE as a specialization. And as a result, we only
have one level of template argument for the innermost
class template. */
diff --git a/gcc/testsuite/g++.dg/template/spec42.C
b/gcc/testsuite/g++.dg/template/spec42.C
new file mode 100644
index 00000000000..cac1264fc9f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/spec42.C
@@ -0,0 +1,17 @@
+// PR c++/115716
+// { dg-do compile }
+template <typename T> struct x {
+ template <typename U> struct y { // { dg-note "used 1 template parameter" }
+ typedef T result2;
+ };
+};
+
+template<>
+template<typename U, typename>
+struct x<int>::y { // { dg-error "redeclared with 2 template parameters" }
+ typedef double result2;
+};
+
+int main() {
+ x<int>::y<int>::result2 xxx2;
+}
diff --git a/gcc/testsuite/g++.dg/template/spec43.C
b/gcc/testsuite/g++.dg/template/spec43.C
new file mode 100644
index 00000000000..d33659dd506
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/spec43.C
@@ -0,0 +1,18 @@
+// PR c++/115716
+// { dg-do compile { target c++20 } }
+template <typename T> struct x {
+ template <typename U> struct y { // { dg-note "original" }
+ typedef T result2;
+ };
+};
+
+template<>
+template<typename U>
+requires true
+struct x<int>::y { // { dg-error "different constraints" }
+ typedef double result2;
+};
+
+int main() {
+ x<int>::y<int>::result2 xxx2;
+}
--
2.44.0
