[PATCH v3] c++: deleting explicitly-defaulted functions [PR116162]
Jason Merrill
jason@redhat.com
Fri Sep 13 16:43:06 GMT 2024
On 9/12/24 3:12 PM, Marek Polacek wrote:
> On Wed, Sep 11, 2024 at 10:25:34PM -0400, Jason Merrill wrote:
>> On 9/11/24 4:08 PM, Marek Polacek wrote:
>>> @@ -6503,10 +6504,17 @@ check_bases_and_members (tree t)
>>> bool fn_const_p = (copy == 2);
>>> if (fn_const_p && !imp_const_p)
>>> - /* If the function is defaulted outside the class, we just
>>> - give the synthesis error. Core Issue #1331 says this is
>>> - no longer ill-formed, it is defined as deleted instead. */
>>> - DECL_DELETED_FN (fn) = true;
>>> + {
>>> + tree implicit_fn
>>> + = implicitly_declare_fn (kind, DECL_CONTEXT (fn),
>>> + /*const_p=*/false,
>>> + /*pattern_fn=*/NULL_TREE,
>>> + /*inherited_parms=*/NULL_TREE);
>>> + /* If the function is defaulted outside the class, we just
>>> + give the synthesis error. Core Issue #1331 says this is
>>> + no longer ill-formed, it is defined as deleted instead. */
>>> + maybe_delete_defaulted_fn (fn, implicit_fn);
>>> + }
>>
>> Since we're about to call defaulted_late_check anyway, can we remove all the
>> copy ctor handling here? I don't want to call implicitly_declare_fn twice
>> for the same function.
>
> Yeh, I should've done that; it wasn't complicated in the end.
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>
> -- >8 --
> This PR points out the we're not implementing [dcl.fct.def.default]
> properly. Consider e.g.
>
> struct C {
> C(const C&&) = default;
> };
>
> where we wrongly emit an error, but the move ctor should be just =deleted.
> According to [dcl.fct.def.default], if the type of the special member
> function differs from the type of the corresponding special member function
> that would have been implicitly declared in a way other than as allowed
> by 2.1-4, the function is defined as deleted. There's an exception for
> assignment operators in which case the program is ill-formed.
>
> clang++ has a warning for when we delete an explicitly-defaulted function
> so this patch adds it too.
Does clang warn by default for template instantiations? I'm concerned
about getting a bunch of noise warnings, but perhaps I'm overestimating
how common that would be.
> I'm also downgrading an error to a pedwarn
> in C++17 since the code compiles in C++20.
>
> PR c++/116162
>
> gcc/c-family/ChangeLog:
>
> * c.opt (Wdefaulted-function-deleted): New.
>
> gcc/cp/ChangeLog:
>
> * class.cc (check_bases_and_members): Don't set DECL_DELETED_FN here,
> leave it to defaulted_late_check.
> * cp-tree.h (maybe_delete_defaulted_fn): Declare.
> (defaulted_late_check): Add a tristate parameter.
> * method.cc (maybe_delete_defaulted_fn): New.
> (defaulted_late_check): Add a tristate parameter. Call
> maybe_delete_defaulted_fn instead of giving an error.
>
> gcc/ChangeLog:
>
> * doc/invoke.texi: Document -Wdefaulted-function-deleted.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/defaulted15.C: Add dg-warning/dg-error.
> * g++.dg/cpp0x/defaulted51.C: Likewise.
> * g++.dg/cpp0x/defaulted52.C: Likewise.
> * g++.dg/cpp0x/defaulted53.C: Likewise.
> * g++.dg/cpp0x/defaulted54.C: Likewise.
> * g++.dg/cpp0x/defaulted56.C: Likewise.
> * g++.dg/cpp0x/defaulted57.C: Likewise.
> * g++.dg/cpp0x/defaulted58.C: Likewise.
> * g++.dg/cpp0x/defaulted59.C: Likewise.
> * g++.dg/cpp0x/defaulted63.C: New test.
> * g++.dg/cpp0x/defaulted64.C: New test.
> * g++.dg/cpp0x/defaulted65.C: New test.
> * g++.dg/cpp23/defaulted1.C: New test.
> ---
> gcc/c-family/c.opt | 4 ++
> gcc/cp/class.cc | 27 ++------
> gcc/cp/cp-tree.h | 3 +-
> gcc/cp/method.cc | 88 +++++++++++++++++++++---
> gcc/doc/invoke.texi | 9 +++
> gcc/testsuite/g++.dg/cpp0x/defaulted15.C | 3 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted51.C | 3 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted52.C | 3 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted53.C | 3 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted54.C | 2 +
> gcc/testsuite/g++.dg/cpp0x/defaulted56.C | 6 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted57.C | 6 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted58.C | 2 +
> gcc/testsuite/g++.dg/cpp0x/defaulted59.C | 3 +-
> gcc/testsuite/g++.dg/cpp0x/defaulted63.C | 39 +++++++++++
> gcc/testsuite/g++.dg/cpp0x/defaulted64.C | 27 ++++++++
> gcc/testsuite/g++.dg/cpp0x/defaulted65.C | 25 +++++++
> gcc/testsuite/g++.dg/cpp23/defaulted1.C | 23 +++++++
> 18 files changed, 236 insertions(+), 40 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/defaulted63.C
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/defaulted64.C
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/defaulted65.C
> create mode 100644 gcc/testsuite/g++.dg/cpp23/defaulted1.C
>
> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> index ec23249c959..98a35f043c7 100644
> --- a/gcc/c-family/c.opt
> +++ b/gcc/c-family/c.opt
> @@ -629,6 +629,10 @@ Wdeclaration-missing-parameter-type
> C ObjC Var(warn_declaration_missing_parameter) Warning Init(1)
> Warn for missing parameter types in function declarations.
>
> +Wdefaulted-function-deleted
> +C++ ObjC++ Var(warn_defaulted_fn_deleted) Init(1) Warning
> +Warn when an explicitly defaulted function is deleted.
> +
> Wdelete-incomplete
> C++ ObjC++ Var(warn_delete_incomplete) Init(1) Warning
> Warn when deleting a pointer to incomplete type.
> diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc
> index 950d83b0ea4..646072d4f20 100644
> --- a/gcc/cp/class.cc
> +++ b/gcc/cp/class.cc
> @@ -6488,27 +6488,14 @@ check_bases_and_members (tree t)
> for (fn = TYPE_FIELDS (t); fn; fn = DECL_CHAIN (fn))
> if (DECL_DECLARES_FUNCTION_P (fn)
> && !DECL_ARTIFICIAL (fn)
> - && DECL_DEFAULTED_IN_CLASS_P (fn))
> - {
> + && DECL_DEFAULTED_IN_CLASS_P (fn)
> /* ...except handle comparisons later, in finish_struct_1. */
> - if (special_function_p (fn) == sfk_comparison)
> - continue;
> -
> - int copy = copy_fn_p (fn);
> - if (copy > 0)
> - {
> - bool imp_const_p
> - = (DECL_CONSTRUCTOR_P (fn) ? !cant_have_const_ctor
> - : !no_const_asn_ref);
> - bool fn_const_p = (copy == 2);
> -
> - if (fn_const_p && !imp_const_p)
> - /* If the function is defaulted outside the class, we just
> - give the synthesis error. Core Issue #1331 says this is
> - no longer ill-formed, it is defined as deleted instead. */
> - DECL_DELETED_FN (fn) = true;
> - }
> - defaulted_late_check (fn);
> + && special_function_p (fn) != sfk_comparison)
> + {
> + bool imp_const_p
> + = (DECL_CONSTRUCTOR_P (fn) ? !cant_have_const_ctor
> + : !no_const_asn_ref);
> + defaulted_late_check (fn, imp_const_p);
> }
>
> if (LAMBDA_TYPE_P (t))
> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> index 7baa2ccbe1e..32252e7f32f 100644
> --- a/gcc/cp/cp-tree.h
> +++ b/gcc/cp/cp-tree.h
> @@ -6929,7 +6929,8 @@ extern bool type_build_ctor_call (tree);
> extern bool type_build_dtor_call (tree);
> extern void explain_non_literal_class (tree);
> extern void inherit_targ_abi_tags (tree);
> -extern void defaulted_late_check (tree);
> +extern void maybe_delete_defaulted_fn (tree, tree);
> +extern void defaulted_late_check (tree, tristate = tristate::unknown ());
> extern bool defaultable_fn_check (tree);
> extern void check_abi_tags (tree);
> extern tree missing_abi_tags (tree);
> diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
> index 21c06c744c9..c1c07a4927f 100644
> --- a/gcc/cp/method.cc
> +++ b/gcc/cp/method.cc
> @@ -3509,11 +3509,79 @@ implicitly_declare_fn (special_function_kind kind, tree type,
> return fn;
> }
>
> +/* Mark an explicitly defaulted function FN as =deleted and warn.
> + IMPLICIT_FN is the corresponding special member function that
> + would have been implicitly declared. */
> +
> +void
> +maybe_delete_defaulted_fn (tree fn, tree implicit_fn)
> +{
> + if (DECL_ARTIFICIAL (fn) || !DECL_DEFAULTED_IN_CLASS_P (fn))
> + return;
> +
> + DECL_DELETED_FN (fn) = true;
> +
> + if (!warn_defaulted_fn_deleted)
> + return;
> +
> + auto_diagnostic_group d;
> + const special_function_kind kind = special_function_p (fn);
> + tree parmtype
> + = TREE_VALUE (DECL_XOBJ_MEMBER_FUNCTION_P (fn)
> + ? TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)))
> + : FUNCTION_FIRST_USER_PARMTYPE (fn));
> + const bool pedwarn_p
> + = (cxx_dialect < cxx20
> + /* [dcl.fct.def.default] "if F1 is an assignment operator"... */
> + || (SFK_ASSIGN_P (kind)
> + /* "and the return type of F1 differs from the return type of F2" */
> + && (!same_type_p (TREE_TYPE (TREE_TYPE (fn)),
> + TREE_TYPE (TREE_TYPE (implicit_fn)))
> + /* "or F1's non-object parameter type is not a reference,
> + the program is ill-formed" */
> + || !TYPE_REF_P (parmtype))));
I'd keep the cases that are ill-formed in C++20 errors; pedwarn for
pre-C++20 in the cases that are warnings in C++20.
> + const char *wmsg;
> + switch (kind)
> + {
> + case sfk_copy_constructor:
> + wmsg = G_("explicitly defaulted copy constructor is implicitly deleted "
> + "because its declared type does not match the type of an "
> + "implicit copy constructor");
> + break;
> + case sfk_move_constructor:
> + wmsg = G_("explicitly defaulted move constructor is implicitly deleted "
> + "because its declared type does not match the type of an "
> + "implicit move constructor");
> + break;
> + case sfk_copy_assignment:
> + wmsg = G_("explicitly defaulted copy assignment operator is implicitly "
> + "deleted because its declared type does not match the type "
> + "of an implicit copy assignment operator");
> + break;
> + case sfk_move_assignment:
> + wmsg = G_("explicitly defaulted move assignment operator is implicitly "
> + "deleted because its declared type does not match the type "
> + "of an implicit move assignment operator");
> + break;
> + default:
> + gcc_unreachable ();
> + }
> + if (emit_diagnostic (pedwarn_p ? DK_PEDWARN : DK_WARNING,
> + DECL_SOURCE_LOCATION (fn),
> + OPT_Wdefaulted_function_deleted,
> + wmsg))
> + inform (DECL_SOURCE_LOCATION (fn),
> + "expected signature: %qD", implicit_fn);
> +}
> +
> /* Gives any errors about defaulted functions which need to be deferred
> - until the containing class is complete. */
> + until the containing class is complete. IMP_CONST is false or true
> + if we are called from check_bases_and_members and signals whether
> + the implicit function has a non-object parameter of type const C&. */
>
> void
> -defaulted_late_check (tree fn)
> +defaulted_late_check (tree fn, tristate imp_const/*=tristate::unknown()*/)
> {
> /* Complain about invalid signature for defaulted fn. */
> tree ctx = DECL_CONTEXT (fn);
> @@ -3534,8 +3602,14 @@ defaulted_late_check (tree fn)
> }
>
> bool fn_const_p = (copy_fn_p (fn) == 2);
> + /* "if F2 has a non-object parameter of type const C&, the corresponding
> + non-object parameter of F1 may be of type C&." But not the other way
> + around. */
> + if (fn_const_p && imp_const.is_false ())
> + fn_const_p = false;
> tree implicit_fn = implicitly_declare_fn (kind, ctx, fn_const_p,
> - NULL, NULL);
> + /*pattern_fn=*/NULL_TREE,
> + /*inherited_parms=*/NULL_TREE);
> tree eh_spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (implicit_fn));
>
> /* Includes special handling for a default xobj operator. */
> @@ -3564,13 +3638,7 @@ defaulted_late_check (tree fn)
> if (!same_type_p (TREE_TYPE (TREE_TYPE (fn)),
> TREE_TYPE (TREE_TYPE (implicit_fn)))
> || !compare_fn_params (fn, implicit_fn))
> - {
> - auto_diagnostic_group d;
> - error ("defaulted declaration %q+D does not match the "
> - "expected signature", fn);
> - inform (DECL_SOURCE_LOCATION (fn),
> - "expected signature: %qD", implicit_fn);
> - }
> + maybe_delete_defaulted_fn (fn, implicit_fn);
>
> if (DECL_DELETED_FN (implicit_fn))
> {
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index a6cd5111d47..b7a75a299e7 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -251,6 +251,7 @@ in the following sections.
> -Wcomma-subscript -Wconditionally-supported
> -Wno-conversion-null -Wctad-maybe-unsupported
> -Wctor-dtor-privacy -Wdangling-reference
> +-Wno-defaulted-function-deleted
> -Wno-delete-incomplete
> -Wdelete-non-virtual-dtor -Wno-deprecated-array-compare
> -Wdeprecated-copy -Wdeprecated-copy-dtor
> @@ -4798,6 +4799,14 @@ not caught by reference. @option{-Wcatch-value} is enabled by @option{-Wall}.
> @item -Wconditionally-supported @r{(C++ and Objective-C++ only)}
> Warn for conditionally-supported (C++11 [intro.defs]) constructs.
>
> +@opindex Wdefaulted-function-deleted
> +@opindex Wno-defaulted-function-deleted
> +@item -Wno-defaulted-function-deleted @r{(C++ and Objective-C++ only)}
> +Warn when an explicitly defaulted function is deleted by the compiler.
> +That can occur when the function's declared type does not match the type
> +of the function that would have been implicitly declared. This warning
> +is enabled by default.
> +
> @opindex Wdelete-incomplete
> @opindex Wno-delete-incomplete
> @item -Wno-delete-incomplete @r{(C++ and Objective-C++ only)}
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted15.C b/gcc/testsuite/g++.dg/cpp0x/defaulted15.C
> index 1e0b3545840..6bd02d74dc3 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted15.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted15.C
> @@ -48,7 +48,8 @@ struct F
>
> struct G: public F
> {
> - G(const G&) = default;
> + G(const G&) = default; // { dg-error "implicitly deleted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
>
> struct H
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted51.C b/gcc/testsuite/g++.dg/cpp0x/defaulted51.C
> index 0a7d308707c..561f8998177 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted51.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted51.C
> @@ -4,7 +4,8 @@
> template<int> struct A
> {
> A();
> - A(volatile A&) = default; // { dg-error "defaulted" }
> + A(volatile A&) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
>
> struct B
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted52.C b/gcc/testsuite/g++.dg/cpp0x/defaulted52.C
> index c617230b493..9c10079362c 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted52.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted52.C
> @@ -13,7 +13,8 @@ template<typename T> struct W
> {
> W();
> // This should now compile and be =deleted.
> - W(const W&) = default;
> + W(const W&) = default; // { dg-error "implicitly deleted" "" { target c++17_down } }
> +// { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> T t;
> };
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted53.C b/gcc/testsuite/g++.dg/cpp0x/defaulted53.C
> index 8147e7e2ad1..cc039672277 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted53.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted53.C
> @@ -14,7 +14,8 @@ struct R
>
> struct S
> {
> - S& operator=(const S&) = default;
> + S& operator=(const S&) = default; // { dg-error "implicitly deleted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> M m;
> };
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted54.C b/gcc/testsuite/g++.dg/cpp0x/defaulted54.C
> index f8ddc4e47ce..2ca078acab5 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted54.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted54.C
> @@ -11,6 +11,8 @@ template<typename T> struct W
> {
> W();
> W(const W&) = default; // { dg-error "binding" }
> +// { dg-error "implicitly deleted" "" { target c++17_down } .-1 }
> +// { dg-warning "implicitly deleted" "" { target c++20 } .-2 }
> T t;
> };
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted56.C b/gcc/testsuite/g++.dg/cpp0x/defaulted56.C
> index e7ce12c5566..0e36fd293f6 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted56.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted56.C
> @@ -11,12 +11,14 @@ struct S
>
> struct T
> {
> - constexpr T(volatile T &) = default; // { dg-error "defaulted" }
> + constexpr T(volatile T &) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
>
> struct U
> {
> - constexpr U(const volatile U &) = default; // { dg-error "defaulted" }
> + constexpr U(const volatile U &) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
>
> struct V
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted57.C b/gcc/testsuite/g++.dg/cpp0x/defaulted57.C
> index 37fb7dd6e1d..feca9662b4a 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted57.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted57.C
> @@ -11,12 +11,14 @@ struct S
>
> struct T
> {
> - T& operator=(volatile T &) = default; // { dg-error "defaulted" }
> + T& operator=(volatile T &) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
>
> struct U
> {
> - U& operator=(const volatile U &) = default; // { dg-error "defaulted" }
> + U& operator=(const volatile U &) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
>
> struct V
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted58.C b/gcc/testsuite/g++.dg/cpp0x/defaulted58.C
> index 920a4ad0c6d..8cb3e0effb9 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted58.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted58.C
> @@ -11,6 +11,8 @@ template<typename T> struct W
> {
> W() = default;
> W& operator=(const W&) = default; // { dg-error "binding" }
> +// { dg-error "implicitly deleted" "" { target c++17_down } .-1 }
> +// { dg-warning "implicitly deleted" "" { target c++20 } .-2 }
> T t;
> };
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted59.C b/gcc/testsuite/g++.dg/cpp0x/defaulted59.C
> index 4f871d7f5b1..26510b4ee33 100644
> --- a/gcc/testsuite/g++.dg/cpp0x/defaulted59.C
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted59.C
> @@ -8,5 +8,6 @@ struct M
>
> struct W : public M
> {
> - W(const W&) = default;
> + W(const W&) = default; // { dg-error "implicitly deleted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> };
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted63.C b/gcc/testsuite/g++.dg/cpp0x/defaulted63.C
> new file mode 100644
> index 00000000000..99f92ff69c5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted63.C
> @@ -0,0 +1,39 @@
> +// PR c++/116162
> +// { dg-do compile { target c++11 } }
> +
> +struct C0 {
> + C0(C0&) = default;
> +};
> +
> +struct C1 {
> + C1(volatile C1&) = default; // { dg-warning "implicitly deleted" "" { target c++20 } }
> + // { dg-error "does not match" "" { target c++17_down } .-1 }
> +};
> +
> +struct C2 {
> + C2(const C2&) = default;
> +};
> +
> +struct C3 {
> + C3(const volatile C3&) = default; // { dg-warning "implicitly deleted" "" { target c++20 } }
> + // { dg-error "does not match" "" { target c++17_down } .-1 }
> +};
> +
> +struct M0 {
> + M0(M0&&) = default;
> +};
> +
> +struct M1 {
> + M1(const M1&&) = default; // { dg-warning "implicitly deleted" "" { target c++20 } }
> + // { dg-error "does not match" "" { target c++17_down } .-1 }
> +};
> +
> +struct M2 {
> + M2(volatile M2&&) = default; // { dg-warning "implicitly deleted" "" { target c++20 } }
> + // { dg-error "does not match" "" { target c++17_down } .-1 }
> +};
> +
> +struct M3 {
> + M3(const volatile M3&&) = default; // { dg-warning "implicitly deleted" "" { target c++20 } }
> + // { dg-error "does not match" "" { target c++17_down } .-1 }
> +};
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted64.C b/gcc/testsuite/g++.dg/cpp0x/defaulted64.C
> new file mode 100644
> index 00000000000..f20030192c3
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted64.C
> @@ -0,0 +1,27 @@
> +// PR c++/116162
> +// { dg-do compile { target c++11 } }
> +
> +struct M
> +{
> + M& operator=(M&&);
> +};
> +
> +struct R
> +{
> + R& operator=(R&&) = default;
> + M m;
> +};
> +
> +struct S
> +{
> + S& operator=(const S&&) = default; // { dg-warning "implicitly deleted" "" { target c++20 } }
> + // { dg-error "does not match" "" { target c++17_down } .-1 }
> +
> + M m;
> +};
> +
> +struct T
> +{
> + T operator=(T&&) = default; // { dg-error "defaulted" }
> + M m;
> +};
> diff --git a/gcc/testsuite/g++.dg/cpp0x/defaulted65.C b/gcc/testsuite/g++.dg/cpp0x/defaulted65.C
> new file mode 100644
> index 00000000000..88ca1d96084
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/defaulted65.C
> @@ -0,0 +1,25 @@
> +// PR c++/116162
> +// { dg-do compile { target c++11 } }
> +
> +struct S
> +{
> + S& operator=(S &&) = default;
> +};
> +
> +struct T
> +{
> + T& operator=(volatile T &&) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> +};
> +
> +struct U
> +{
> + U& operator=(const volatile U &&) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> +};
> +
> +struct V
> +{
> + V& operator=(const V &&) = default; // { dg-error "defaulted" "" { target c++17_down } }
> + // { dg-warning "implicitly deleted" "" { target c++20 } .-1 }
> +};
> diff --git a/gcc/testsuite/g++.dg/cpp23/defaulted1.C b/gcc/testsuite/g++.dg/cpp23/defaulted1.C
> new file mode 100644
> index 00000000000..00cf894fa1d
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp23/defaulted1.C
> @@ -0,0 +1,23 @@
> +// PR c++/116162
> +// { dg-do compile { target c++23 } }
> +
> +struct M
> +{
> + M& operator=(M&);
> +};
> +
> +struct T
> +{
> + // if F1 is an assignment operator, and the return type of F1 differs
> + // from the return type, the program is ill-formed.
> + T operator=(this T&, T&) = default; // { dg-error "defaulted" }
> + M m;
> +};
> +
> +struct U
> +{
> + // if F1's non-object parameter type is not a reference, the program
> + // is ill-formed.
> + U& operator=(this U&, U) = default; // { dg-error "defaulted" }
> + M m;
> +};
>
> base-commit: 19d751601d012bbe31512d26f968e75873a408ab
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