Re: [committed] libstdc++: Find make_error_code and make_error_condition via ADL only
On Mon, 12 Sept 2022 at 11:55, Daniel Krügler wrote:
>
> Am Do., 8. Sept. 2022 um 20:30 Uhr schrieb Jonathan Wakely via
> Libstdc++ :
> >
> > Tested powerpc64le-linux, pushed to trunk.
> >
> > -- >8 --
> >
> > The new proposed resolution for LWG 3629 says that std::error_code and
> > std::error_condition should only use ADL to find their customization
> > points. This means we need to use a poison pill to prevent lookup from
> > finding overloads in the enclosing namespaces.
> >
> > We can also remove the forward declarations of std::make_error_code and
> > std::make_error_condition, because they aren't needed now. ADL can find
> > them anyway (when std is an associated namespace), and unqualified name
> > lookup will not (and should not) find them.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/system_error (__adl_only::make_error_code): Add
> > deleted function.
> > (__adl_only::make_error_condition): Likewise.
> > (error_code::error_code(ErrorCodeEnum)): Add using-declaration
> > for deleted function.
> > (error_condition::error_condition(ErrorConditionEnum)):
> > Likewise.
> > * testsuite/19_diagnostics/error_code/cons/lwg3629.cc: New test.
> > * testsuite/19_diagnostics/error_condition/cons/lwg3629.cc: New
> > test.
> > ---
> [..]
> > +// { dg-do compile { target c++11 } }
> > +
> > +// 3629. make_error_code and make_error_condition are customization points
> > +// Verify that make_error_code is looked up using ADL only.
> > +
> > +namespace user
> > +{
> > + struct E1;
> > +}
> > +
> > +// N.B. not in associated namespace of E1, and declared before
> > .
> > +user::E1 make_error_code(user::E1);
> > +
> > +#include // declares std::make_error_code(future_errc)
> > +#include
> > +
> > +namespace user
> > +{
> > + struct E1
> > + {
> > +operator std::error_code() const;
> > + };
> > +
> > + struct E2
> > + {
> > +operator std::future_errc() const;
> > + };
> > +
> > + struct E3
> > + {
> > +operator std::errc() const;
> > + };
> > +}
> > +
> > +template<> struct std::is_error_code_enum : std::true_type { };
> > +template<> struct std::is_error_code_enum : std::true_type { };
> > +template<> struct std::is_error_code_enum : std::true_type { };
> > +
> > +// ::make_error_code(E1) should not be found by name lookup.
> > +std::error_code e1( user::E1{} ); // { dg-error "here" }
> > +
> > +// std::make_error_code(errc) should not be found by name lookup.
> > +std::error_code e2( user::E2{} ); // { dg-error "here" }
>
> (1) Unless I'm misunderstanding something here, the comment above
> doesn't match here, it should mention (std::)future_errc instead.
>
> > +// std::make_error_code(future_errc) should not be found by name lookup.
> > +std::error_code e3( user::E3{} ); // { dg-error "here" }
>
> (2) Unless I'm misunderstanding something here, the comment above
> doesn't match here, it should mention (std::)errc instead.
>
> > +// { dg-error "use of deleted function" "" { target *-*-* } 0 }
> > diff --git
> > a/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
> > b/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
> > new file mode 100644
> > index 000..e34b53de8a1
> > --- /dev/null
> > +++ b/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
> > @@ -0,0 +1,48 @@
> > +// { dg-do compile { target c++11 } }
> > +
> > +// 3629. make_error_code and make_error_condition are customization points
> > +// Verify that make_error_condition is looked up using ADL only.
> > +
> > +namespace user
> > +{
> > + struct E1;
> > +}
> > +
> > +// N.B. not in associated namespace of E1, and declared before
> > .
> > +user::E1 make_error_condition(user::E1);
> > +
> > +#include // declares std::make_error_condition(future_errc)
> > +#include
> > +
> > +namespace user
> > +{
> > + struct E1
> > + {
> > +operator std::error_code() const;
> > + };
> > +
> > + struct E2
> > + {
> > +operator std::future_errc() const;
> > + };
> > +
> > + struct E3
> > + {
> > +operator std::errc() const;
> > + };
> > +}
> > +
> > +template<> struct std::is_error_condition_enum : std::true_type
> > { };
> > +template<> struct std::is_error_condition_enum : std::true_type
> > { };
> > +template<> struct std::is_error_condition_enum : std::true_type
> > { };
> > +
> > +// ::make_error_condition(E1) should not be found by name lookup.
> > +std::error_condition e1( user::E1{} ); // { dg-error "here" }
> > +
> > +// std::make_error_condition(errc) should not be found by name lookup.
> > +std::error_condition e2( user::E2{} ); // { dg-error "here" }
>
> Ditto here (1)
>
> > +// std::make_error_condition(future_errc) should not be found by name
> > lookup.
> > +std::error_condition e3( user::E3{} ); // { dg-error "here" }
>
> Ditto here (2)
Good catch, thanks.
Fixed by the attached patch, tested x86_64-linux and pushed to trunk.
commit c092d894265f3db59058
Re: [committed] libstdc++: Find make_error_code and make_error_condition via ADL only
Am Do., 8. Sept. 2022 um 20:30 Uhr schrieb Jonathan Wakely via
Libstdc++ :
>
> Tested powerpc64le-linux, pushed to trunk.
>
> -- >8 --
>
> The new proposed resolution for LWG 3629 says that std::error_code and
> std::error_condition should only use ADL to find their customization
> points. This means we need to use a poison pill to prevent lookup from
> finding overloads in the enclosing namespaces.
>
> We can also remove the forward declarations of std::make_error_code and
> std::make_error_condition, because they aren't needed now. ADL can find
> them anyway (when std is an associated namespace), and unqualified name
> lookup will not (and should not) find them.
>
> libstdc++-v3/ChangeLog:
>
> * include/std/system_error (__adl_only::make_error_code): Add
> deleted function.
> (__adl_only::make_error_condition): Likewise.
> (error_code::error_code(ErrorCodeEnum)): Add using-declaration
> for deleted function.
> (error_condition::error_condition(ErrorConditionEnum)):
> Likewise.
> * testsuite/19_diagnostics/error_code/cons/lwg3629.cc: New test.
> * testsuite/19_diagnostics/error_condition/cons/lwg3629.cc: New test.
> ---
[..]
> +// { dg-do compile { target c++11 } }
> +
> +// 3629. make_error_code and make_error_condition are customization points
> +// Verify that make_error_code is looked up using ADL only.
> +
> +namespace user
> +{
> + struct E1;
> +}
> +
> +// N.B. not in associated namespace of E1, and declared before
> .
> +user::E1 make_error_code(user::E1);
> +
> +#include // declares std::make_error_code(future_errc)
> +#include
> +
> +namespace user
> +{
> + struct E1
> + {
> +operator std::error_code() const;
> + };
> +
> + struct E2
> + {
> +operator std::future_errc() const;
> + };
> +
> + struct E3
> + {
> +operator std::errc() const;
> + };
> +}
> +
> +template<> struct std::is_error_code_enum : std::true_type { };
> +template<> struct std::is_error_code_enum : std::true_type { };
> +template<> struct std::is_error_code_enum : std::true_type { };
> +
> +// ::make_error_code(E1) should not be found by name lookup.
> +std::error_code e1( user::E1{} ); // { dg-error "here" }
> +
> +// std::make_error_code(errc) should not be found by name lookup.
> +std::error_code e2( user::E2{} ); // { dg-error "here" }
(1) Unless I'm misunderstanding something here, the comment above
doesn't match here, it should mention (std::)future_errc instead.
> +// std::make_error_code(future_errc) should not be found by name lookup.
> +std::error_code e3( user::E3{} ); // { dg-error "here" }
(2) Unless I'm misunderstanding something here, the comment above
doesn't match here, it should mention (std::)errc instead.
> +// { dg-error "use of deleted function" "" { target *-*-* } 0 }
> diff --git
> a/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
> b/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
> new file mode 100644
> index 000..e34b53de8a1
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
> @@ -0,0 +1,48 @@
> +// { dg-do compile { target c++11 } }
> +
> +// 3629. make_error_code and make_error_condition are customization points
> +// Verify that make_error_condition is looked up using ADL only.
> +
> +namespace user
> +{
> + struct E1;
> +}
> +
> +// N.B. not in associated namespace of E1, and declared before
> .
> +user::E1 make_error_condition(user::E1);
> +
> +#include // declares std::make_error_condition(future_errc)
> +#include
> +
> +namespace user
> +{
> + struct E1
> + {
> +operator std::error_code() const;
> + };
> +
> + struct E2
> + {
> +operator std::future_errc() const;
> + };
> +
> + struct E3
> + {
> +operator std::errc() const;
> + };
> +}
> +
> +template<> struct std::is_error_condition_enum : std::true_type {
> };
> +template<> struct std::is_error_condition_enum : std::true_type {
> };
> +template<> struct std::is_error_condition_enum : std::true_type {
> };
> +
> +// ::make_error_condition(E1) should not be found by name lookup.
> +std::error_condition e1( user::E1{} ); // { dg-error "here" }
> +
> +// std::make_error_condition(errc) should not be found by name lookup.
> +std::error_condition e2( user::E2{} ); // { dg-error "here" }
Ditto here (1)
> +// std::make_error_condition(future_errc) should not be found by name lookup.
> +std::error_condition e3( user::E3{} ); // { dg-error "here" }
Ditto here (2)
> +// { dg-error "use of deleted function" "" { target *-*-* } 0 }
> --
> 2.37.3
- Daniel
[committed] libstdc++: Find make_error_code and make_error_condition via ADL only
Tested powerpc64le-linux, pushed to trunk.
-- >8 --
The new proposed resolution for LWG 3629 says that std::error_code and
std::error_condition should only use ADL to find their customization
points. This means we need to use a poison pill to prevent lookup from
finding overloads in the enclosing namespaces.
We can also remove the forward declarations of std::make_error_code and
std::make_error_condition, because they aren't needed now. ADL can find
them anyway (when std is an associated namespace), and unqualified name
lookup will not (and should not) find them.
libstdc++-v3/ChangeLog:
* include/std/system_error (__adl_only::make_error_code): Add
deleted function.
(__adl_only::make_error_condition): Likewise.
(error_code::error_code(ErrorCodeEnum)): Add using-declaration
for deleted function.
(error_condition::error_condition(ErrorConditionEnum)):
Likewise.
* testsuite/19_diagnostics/error_code/cons/lwg3629.cc: New test.
* testsuite/19_diagnostics/error_condition/cons/lwg3629.cc: New test.
---
libstdc++-v3/include/std/system_error | 18 +--
.../19_diagnostics/error_code/cons/lwg3629.cc | 48 +++
.../error_condition/cons/lwg3629.cc | 48 +++
3 files changed, 109 insertions(+), 5 deletions(-)
create mode 100644
libstdc++-v3/testsuite/19_diagnostics/error_code/cons/lwg3629.cc
create mode 100644
libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
diff --git a/libstdc++-v3/include/std/system_error
b/libstdc++-v3/include/std/system_error
index 050439427cc..e12bb2f0e1e 100644
--- a/libstdc++-v3/include/std/system_error
+++ b/libstdc++-v3/include/std/system_error
@@ -195,7 +195,11 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
* @{
*/
- error_code make_error_code(errc) noexcept;
+namespace __adl_only
+{
+ void make_error_code() = delete;
+ void make_error_condition() = delete;
+}
/** Class error_code
*
@@ -231,7 +235,10 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
template>
error_code(_ErrorCodeEnum __e) noexcept
- { *this = make_error_code(__e); }
+ {
+ using __adl_only::make_error_code;
+ *this = make_error_code(__e);
+ }
error_code(const error_code&) = default;
error_code& operator=(const error_code&) = default;
@@ -330,8 +337,6 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
{ return (__os << __e.category().name() << ':' << __e.value()); }
- error_condition make_error_condition(errc) noexcept;
-
/** Class error_condition
*
* This class represents error conditions that may be visible at an API
@@ -363,7 +368,10 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
template>
error_condition(_ErrorConditionEnum __e) noexcept
- { *this = make_error_condition(__e); }
+ {
+ using __adl_only::make_error_condition;
+ *this = make_error_condition(__e);
+ }
error_condition(const error_condition&) = default;
error_condition& operator=(const error_condition&) = default;
diff --git a/libstdc++-v3/testsuite/19_diagnostics/error_code/cons/lwg3629.cc
b/libstdc++-v3/testsuite/19_diagnostics/error_code/cons/lwg3629.cc
new file mode 100644
index 000..b1e0b7f0c81
--- /dev/null
+++ b/libstdc++-v3/testsuite/19_diagnostics/error_code/cons/lwg3629.cc
@@ -0,0 +1,48 @@
+// { dg-do compile { target c++11 } }
+
+// 3629. make_error_code and make_error_condition are customization points
+// Verify that make_error_code is looked up using ADL only.
+
+namespace user
+{
+ struct E1;
+}
+
+// N.B. not in associated namespace of E1, and declared before .
+user::E1 make_error_code(user::E1);
+
+#include // declares std::make_error_code(future_errc)
+#include
+
+namespace user
+{
+ struct E1
+ {
+operator std::error_code() const;
+ };
+
+ struct E2
+ {
+operator std::future_errc() const;
+ };
+
+ struct E3
+ {
+operator std::errc() const;
+ };
+}
+
+template<> struct std::is_error_code_enum : std::true_type { };
+template<> struct std::is_error_code_enum : std::true_type { };
+template<> struct std::is_error_code_enum : std::true_type { };
+
+// ::make_error_code(E1) should not be found by name lookup.
+std::error_code e1( user::E1{} ); // { dg-error "here" }
+
+// std::make_error_code(errc) should not be found by name lookup.
+std::error_code e2( user::E2{} ); // { dg-error "here" }
+
+// std::make_error_code(future_errc) should not be found by name lookup.
+std::error_code e3( user::E3{} ); // { dg-error "here" }
+
+// { dg-error "use of deleted function" "" { target *-*-* } 0 }
diff --git
a/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
b/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg3629.cc
new file mode 100644
index 000..e34b53de8a1
--- /dev/null
+++ b/libstdc++-v3/testsuite/19_diagnostics/error_condition/cons/lwg36
