| Message ID | 20240705174959.2440677-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: missing SFINAE during alias CTAD [PR115296] | expand |
On Fri, Jul 5, 2024 at 1:50 PM Patrick Palka <ppalka@redhat.com> wrote: > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look > OK for trunk/14? > > -- >8 -- > > During the alias CTAD transformation, if substitution failed for some > guide we should just discard the guide silently. We currently do > discard the guide, but not silently, which causes us to reject the > below testcase due to forming a too-large array type when transforming > the user-defined deduction guides. > > This patch fixes this by passing complain=tf_none instead of > =tf_warning_or_error in the couple of spots where we expect subsitution > to possibly fail and so subsequently check for error_mark_node. Ping. Alternatively we could set complain=tf_none everywhere. > > PR c++/115296 > > gcc/cp/ChangeLog: > > * pt.cc (alias_ctad_tweaks): Pass complain=tf_none to > tsubst_decl and tsubst_constraint_info. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp2a/class-deduction-alias23.C: New test. > --- > gcc/cp/pt.cc | 4 ++-- > .../g++.dg/cpp2a/class-deduction-alias23.C | 20 +++++++++++++++++++ > 2 files changed, 22 insertions(+), 2 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C > > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > index d1316483e24..a382dce8788 100644 > --- a/gcc/cp/pt.cc > +++ b/gcc/cp/pt.cc > @@ -30451,7 +30451,7 @@ alias_ctad_tweaks (tree tmpl, tree uguides) > /* Parms are to have DECL_CHAIN tsubsted, which would be skipped > if cp_unevaluated_operand. */ > cp_evaluated ev; > - g = tsubst_decl (DECL_TEMPLATE_RESULT (f), targs, complain, > + g = tsubst_decl (DECL_TEMPLATE_RESULT (f), targs, tf_none, > /*use_spec_table=*/false); > } > if (g == error_mark_node) > @@ -30478,7 +30478,7 @@ alias_ctad_tweaks (tree tmpl, tree uguides) > { > if (tree outer_targs = outer_template_args (f)) > ci = tsubst_constraint_info (ci, outer_targs, complain, in_decl); > - ci = tsubst_constraint_info (ci, targs, complain, in_decl); > + ci = tsubst_constraint_info (ci, targs, tf_none, in_decl); > } > if (ci == error_mark_node) > continue; > diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C > new file mode 100644 > index 00000000000..e5766586761 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C > @@ -0,0 +1,20 @@ > +// PR c++/115296 > +// { dg-do compile { target c++20 } } > + > +using size_t = decltype(sizeof(0)); > + > +template<class T, size_t N = -1ULL> > +struct span { span(T); }; > + > +template<class T, size_t N> > +span(T(&)[N]) -> span<T, N>; // { dg-bogus "array exceeds maximum" } > + > +template<class T, size_t N> > +requires (sizeof(T(&)[N]) != 42) // { dg-bogus "array exceeds maximum" } > +span(T*) -> span<T, N>; > + > +template<class T> > +using array_view = span<T>; > + > +span x = 0; > +array_view y = 0; > -- > 2.45.2.746.g06e570c0df >
On 7/19/24 10:55 AM, Patrick Palka wrote: > On Fri, Jul 5, 2024 at 1:50 PM Patrick Palka <ppalka@redhat.com> wrote: >> >> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look >> OK for trunk/14? >> >> -- >8 -- >> >> During the alias CTAD transformation, if substitution failed for some >> guide we should just discard the guide silently. We currently do >> discard the guide, but not silently, which causes us to reject the >> below testcase due to forming a too-large array type when transforming >> the user-defined deduction guides. >> >> This patch fixes this by passing complain=tf_none instead of >> =tf_warning_or_error in the couple of spots where we expect subsitution >> to possibly fail and so subsequently check for error_mark_node. > > Ping. Alternatively we could set complain=tf_none everywhere. That sounds better, unless you think there's a reason to have different complain args for different calls. Jason
On Fri, 19 Jul 2024, Jason Merrill wrote: > On 7/19/24 10:55 AM, Patrick Palka wrote: > > On Fri, Jul 5, 2024 at 1:50 PM Patrick Palka <ppalka@redhat.com> wrote: > > > > > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look > > > OK for trunk/14? > > > > > > -- >8 -- > > > > > > During the alias CTAD transformation, if substitution failed for some > > > guide we should just discard the guide silently. We currently do > > > discard the guide, but not silently, which causes us to reject the > > > below testcase due to forming a too-large array type when transforming > > > the user-defined deduction guides. > > > > > > This patch fixes this by passing complain=tf_none instead of > > > =tf_warning_or_error in the couple of spots where we expect subsitution > > > to possibly fail and so subsequently check for error_mark_node. > > > > Ping. Alternatively we could set complain=tf_none everywhere. > > That sounds better, unless you think there's a reason to have different > complain args for different calls. I was initially worried about a stray error_mark_node silently leaking into the rewritten guide signature (since we don't check for error_mark_node after each substitution) but on second thought that seems unlikely. The substitution steps in alias_ctad_tweaks that aren't checked should probably never fail, since they're just reindexing template parameters etc. So like so? -- >8 -- Subject: [PATCH] c++: missing SFINAE during alias CTAD [PR115296] PR c++/115296 gcc/cp/ChangeLog: * pt.cc (alias_ctad_tweaks): Use complain=tf_none instead of tf_warning_or_error. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/class-deduction-alias23.C: New test. --- gcc/cp/pt.cc | 2 +- .../g++.dg/cpp2a/class-deduction-alias23.C | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 45453c0d45a..8e9951a9066 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -30298,7 +30298,7 @@ alias_ctad_tweaks (tree tmpl, tree uguides) (INNERMOST_TEMPLATE_PARMS (fullatparms))); } - tsubst_flags_t complain = tf_warning_or_error; + tsubst_flags_t complain = tf_none; tree aguides = NULL_TREE; tree atparms = INNERMOST_TEMPLATE_PARMS (fullatparms); unsigned natparms = TREE_VEC_LENGTH (atparms); diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C new file mode 100644 index 00000000000..117212c67de --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C @@ -0,0 +1,19 @@ +// PR c++/115296 +// { dg-do compile { target c++20 } } + +using size_t = decltype(sizeof(0)); + +template<class T, size_t N = size_t(-1)> +struct span { span(T); }; + +template<class T, size_t N> +span(T(&)[N]) -> span<T, N>; // { dg-bogus "array exceeds maximum" } + +template<class T, size_t N> +requires (sizeof(T[N]) != 42) // { dg-bogus "array exceeds maximum" } +span(T*) -> span<T, N>; + +template<class T> +using array_view = span<T>; + +array_view x = 0;
On 7/19/24 12:24 PM, Patrick Palka wrote: > On Fri, 19 Jul 2024, Jason Merrill wrote: > >> On 7/19/24 10:55 AM, Patrick Palka wrote: >>> On Fri, Jul 5, 2024 at 1:50 PM Patrick Palka <ppalka@redhat.com> wrote: >>>> >>>> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look >>>> OK for trunk/14? >>>> >>>> -- >8 -- >>>> >>>> During the alias CTAD transformation, if substitution failed for some >>>> guide we should just discard the guide silently. We currently do >>>> discard the guide, but not silently, which causes us to reject the >>>> below testcase due to forming a too-large array type when transforming >>>> the user-defined deduction guides. >>>> >>>> This patch fixes this by passing complain=tf_none instead of >>>> =tf_warning_or_error in the couple of spots where we expect subsitution >>>> to possibly fail and so subsequently check for error_mark_node. >>> >>> Ping. Alternatively we could set complain=tf_none everywhere. >> >> That sounds better, unless you think there's a reason to have different >> complain args for different calls. > > I was initially worried about a stray error_mark_node silently leaking > into the rewritten guide signature (since we don't check for > error_mark_node after each substitution) but on second thought that > seems unlikely. The substitution steps in alias_ctad_tweaks that > aren't checked should probably never fail, since they're just reindexing > template parameters etc. > > So like so? OK. > -- >8 -- > > Subject: [PATCH] c++: missing SFINAE during alias CTAD [PR115296] > > PR c++/115296 > > gcc/cp/ChangeLog: > > * pt.cc (alias_ctad_tweaks): Use complain=tf_none > instead of tf_warning_or_error. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp2a/class-deduction-alias23.C: New test. > --- > gcc/cp/pt.cc | 2 +- > .../g++.dg/cpp2a/class-deduction-alias23.C | 19 +++++++++++++++++++ > 2 files changed, 20 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C > > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > index 45453c0d45a..8e9951a9066 100644 > --- a/gcc/cp/pt.cc > +++ b/gcc/cp/pt.cc > @@ -30298,7 +30298,7 @@ alias_ctad_tweaks (tree tmpl, tree uguides) > (INNERMOST_TEMPLATE_PARMS (fullatparms))); > } > > - tsubst_flags_t complain = tf_warning_or_error; > + tsubst_flags_t complain = tf_none; > tree aguides = NULL_TREE; > tree atparms = INNERMOST_TEMPLATE_PARMS (fullatparms); > unsigned natparms = TREE_VEC_LENGTH (atparms); > diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C > new file mode 100644 > index 00000000000..117212c67de > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C > @@ -0,0 +1,19 @@ > +// PR c++/115296 > +// { dg-do compile { target c++20 } } > + > +using size_t = decltype(sizeof(0)); > + > +template<class T, size_t N = size_t(-1)> > +struct span { span(T); }; > + > +template<class T, size_t N> > +span(T(&)[N]) -> span<T, N>; // { dg-bogus "array exceeds maximum" } > + > +template<class T, size_t N> > +requires (sizeof(T[N]) != 42) // { dg-bogus "array exceeds maximum" } > +span(T*) -> span<T, N>; > + > +template<class T> > +using array_view = span<T>; > + > +array_view x = 0;
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index d1316483e24..a382dce8788 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -30451,7 +30451,7 @@ alias_ctad_tweaks (tree tmpl, tree uguides) /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if cp_unevaluated_operand. */ cp_evaluated ev; - g = tsubst_decl (DECL_TEMPLATE_RESULT (f), targs, complain, + g = tsubst_decl (DECL_TEMPLATE_RESULT (f), targs, tf_none, /*use_spec_table=*/false); } if (g == error_mark_node) @@ -30478,7 +30478,7 @@ alias_ctad_tweaks (tree tmpl, tree uguides) { if (tree outer_targs = outer_template_args (f)) ci = tsubst_constraint_info (ci, outer_targs, complain, in_decl); - ci = tsubst_constraint_info (ci, targs, complain, in_decl); + ci = tsubst_constraint_info (ci, targs, tf_none, in_decl); } if (ci == error_mark_node) continue; diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C new file mode 100644 index 00000000000..e5766586761 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias23.C @@ -0,0 +1,20 @@ +// PR c++/115296 +// { dg-do compile { target c++20 } } + +using size_t = decltype(sizeof(0)); + +template<class T, size_t N = -1ULL> +struct span { span(T); }; + +template<class T, size_t N> +span(T(&)[N]) -> span<T, N>; // { dg-bogus "array exceeds maximum" } + +template<class T, size_t N> +requires (sizeof(T(&)[N]) != 42) // { dg-bogus "array exceeds maximum" } +span(T*) -> span<T, N>; + +template<class T> +using array_view = span<T>; + +span x = 0; +array_view y = 0;