c++: ICE during aggr CTAD for member tmpl [PR105476]
Commit Message
Here we're crashing from maybe_aggr_guide ultimately because
processing_template_decl isn't set when partially instantiating the
guide's parameter list. This causes us to prematurely force completion
of the dependent type Visitor_functior<Fn>, which fails and results in
an unexpected error_mark_node.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk/12.2?
PR c++/105476
gcc/cp/ChangeLog:
* pt.cc (maybe_aggr_guide): Set processing_template_decl when
partially instantiating the guide's parameter list.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/class-deduction-aggr13.C: New test.
* g++.dg/cpp2a/class-deduction-aggr13a.C: New test.
---
gcc/cp/pt.cc | 6 +++++-
.../g++.dg/cpp2a/class-deduction-aggr13.C | 11 +++++++++++
.../g++.dg/cpp2a/class-deduction-aggr13a.C | 18 ++++++++++++++++++
3 files changed, 34 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13a.C
Comments
On 5/4/22 10:09, Patrick Palka wrote:
> Here we're crashing from maybe_aggr_guide ultimately because
> processing_template_decl isn't set when partially instantiating the
> guide's parameter list. This causes us to prematurely force completion
> of the dependent type Visitor_functior<Fn>, which fails and results in
> an unexpected error_mark_node.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk/12.2?
OK.
> PR c++/105476
>
> gcc/cp/ChangeLog:
>
> * pt.cc (maybe_aggr_guide): Set processing_template_decl when
> partially instantiating the guide's parameter list.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/class-deduction-aggr13.C: New test.
> * g++.dg/cpp2a/class-deduction-aggr13a.C: New test.
> ---
> gcc/cp/pt.cc | 6 +++++-
> .../g++.dg/cpp2a/class-deduction-aggr13.C | 11 +++++++++++
> .../g++.dg/cpp2a/class-deduction-aggr13a.C | 18 ++++++++++++++++++
> 3 files changed, 34 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13.C
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13a.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index ac002907a41..2bec47dc295 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -29569,7 +29569,11 @@ maybe_aggr_guide (tree tmpl, tree init, vec<tree,va_gc> *args)
> PARMS, so that its template level is properly reduced and we don't get
> mismatches when deducing types using the guide with PARMS. */
> if (member_template_p)
> - parms = tsubst (parms, DECL_TI_ARGS (tmpl), complain, init);
> + {
> + ++processing_template_decl;
> + parms = tsubst (parms, DECL_TI_ARGS (tmpl), complain, init);
> + --processing_template_decl;
> + }
> }
> else if (TREE_CODE (init) == TREE_LIST)
> {
> diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13.C
> new file mode 100644
> index 00000000000..aa8032c60b5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13.C
> @@ -0,0 +1,11 @@
> +// PR c++/105476
> +// { dg-do compile { target c++20 } }
> +
> +template<class> struct Visitor_functor;
> +
> +template<class> struct Events {
> + template<class... Fn> struct Visitor : Visitor_functor<Fn>::type_t... { };
> +};
> +
> +using ev_t = Events<int>;
> +ev_t::Visitor v = { {} }; // { dg-error "too many initializers" }
> diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13a.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13a.C
> new file mode 100644
> index 00000000000..69ae5dd4b60
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-aggr13a.C
> @@ -0,0 +1,18 @@
> +// PR c++/105476
> +// { dg-do compile { target c++20 } }
> +// A valid version of class-deduction-aggr13.C.
> +
> +template<class> struct Visitor_functor;
> +
> +template<> struct Visitor_functor<int> {
> + using type_t = int;
> +};
> +
> +template<class T> struct Events {
> + template<class Fn=T> struct Visitor {
> + Visitor_functor<Fn>::type_t t;
> + };
> +};
> +
> +using ev_t = Events<int>;
> +ev_t::Visitor v = { {} };
@@ -29569,7 +29569,11 @@ maybe_aggr_guide (tree tmpl, tree init, vec<tree,va_gc> *args)
PARMS, so that its template level is properly reduced and we don't get
mismatches when deducing types using the guide with PARMS. */
if (member_template_p)
- parms = tsubst (parms, DECL_TI_ARGS (tmpl), complain, init);
+ {
+ ++processing_template_decl;
+ parms = tsubst (parms, DECL_TI_ARGS (tmpl), complain, init);
+ --processing_template_decl;
+ }
}
else if (TREE_CODE (init) == TREE_LIST)
{
new file mode 100644
@@ -0,0 +1,11 @@
+// PR c++/105476
+// { dg-do compile { target c++20 } }
+
+template<class> struct Visitor_functor;
+
+template<class> struct Events {
+ template<class... Fn> struct Visitor : Visitor_functor<Fn>::type_t... { };
+};
+
+using ev_t = Events<int>;
+ev_t::Visitor v = { {} }; // { dg-error "too many initializers" }
new file mode 100644
@@ -0,0 +1,18 @@
+// PR c++/105476
+// { dg-do compile { target c++20 } }
+// A valid version of class-deduction-aggr13.C.
+
+template<class> struct Visitor_functor;
+
+template<> struct Visitor_functor<int> {
+ using type_t = int;
+};
+
+template<class T> struct Events {
+ template<class Fn=T> struct Visitor {
+ Visitor_functor<Fn>::type_t t;
+ };
+};
+
+using ev_t = Events<int>;
+ev_t::Visitor v = { {} };