| Message ID | ZuM9OjoNFNapkIjh@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] c++: deleting explicitly-defaulted functions [PR116162] | expand |
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
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)))); + + 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; +};