* [PATCH] c++: alias template of non-template class [PR112633]
@ 2023-11-22 17:26 Patrick Palka
2023-11-22 18:13 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2023-11-22 17:26 UTC (permalink / raw)
To: gcc-patches; +Cc: jason, Patrick Palka
Bootstrapped and regtested on x86-64-pc-linux-gnu, does this look OK for
trunk/13?
-- >8 --
The entering_scope adjustment in tsubst_aggr_type assumes if an alias is
dependent, then so is the aliased type (and therefore it has template info)
but that's not true for the dependent alias template specialization ty1<T>
below which aliases the non-template class A.
PR c++/112633
gcc/cp/ChangeLog:
* pt.cc (tsubst_aggr_type): Handle empty TYPE_TEMPLATE_INFO
in the entering_scope adjustment.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/alias-decl-75.C: New test.
---
gcc/cp/pt.cc | 1 +
gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C | 13 +++++++++++++
2 files changed, 14 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index ed681afb5d4..68ce4a87372 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -13976,6 +13976,7 @@ tsubst_aggr_type (tree t,
if (entering_scope
&& CLASS_TYPE_P (t)
&& dependent_type_p (t)
+ && TYPE_TEMPLATE_INFO (t)
&& TYPE_CANONICAL (t) == TREE_TYPE (TYPE_TI_TEMPLATE (t)))
t = TYPE_CANONICAL (t);
diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C b/gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C
new file mode 100644
index 00000000000..1a73a99856e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C
@@ -0,0 +1,13 @@
+// PR c++/112633
+// { dg-do compile { target c++11 } }
+
+struct A { using type = void; };
+
+template<class>
+using ty1 = A;
+
+template<class T>
+using ty2 = typename ty1<T>::type;
+
+template<class T>
+ty2<T> f();
--
2.43.0.rc1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] c++: alias template of non-template class [PR112633]
2023-11-22 17:26 [PATCH] c++: alias template of non-template class [PR112633] Patrick Palka
@ 2023-11-22 18:13 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2023-11-22 18:13 UTC (permalink / raw)
To: Patrick Palka, gcc-patches
On 11/22/23 12:26, Patrick Palka wrote:
> Bootstrapped and regtested on x86-64-pc-linux-gnu, does this look OK for
> trunk/13?
OK.
> -- >8 --
>
> The entering_scope adjustment in tsubst_aggr_type assumes if an alias is
> dependent, then so is the aliased type (and therefore it has template info)
> but that's not true for the dependent alias template specialization ty1<T>
> below which aliases the non-template class A.
>
> PR c++/112633
>
> gcc/cp/ChangeLog:
>
> * pt.cc (tsubst_aggr_type): Handle empty TYPE_TEMPLATE_INFO
> in the entering_scope adjustment.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/alias-decl-75.C: New test.
> ---
> gcc/cp/pt.cc | 1 +
> gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index ed681afb5d4..68ce4a87372 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -13976,6 +13976,7 @@ tsubst_aggr_type (tree t,
> if (entering_scope
> && CLASS_TYPE_P (t)
> && dependent_type_p (t)
> + && TYPE_TEMPLATE_INFO (t)
> && TYPE_CANONICAL (t) == TREE_TYPE (TYPE_TI_TEMPLATE (t)))
> t = TYPE_CANONICAL (t);
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C b/gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C
> new file mode 100644
> index 00000000000..1a73a99856e
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-75.C
> @@ -0,0 +1,13 @@
> +// PR c++/112633
> +// { dg-do compile { target c++11 } }
> +
> +struct A { using type = void; };
> +
> +template<class>
> +using ty1 = A;
> +
> +template<class T>
> +using ty2 = typename ty1<T>::type;
> +
> +template<class T>
> +ty2<T> f();
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