* [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] @ 2023-08-10 16:09 Patrick Palka 2023-08-10 17:22 ` Jason Merrill 0 siblings, 1 reply; 6+ messages in thread From: Patrick Palka @ 2023-08-10 16:09 UTC (permalink / raw) To: gcc-patches; +Cc: jason, Patrick Palka Booststrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk and perhaps 13? -- >8 -- We shouldn't issue a "declared static but never defined" warning for a deduction guide (declared in an anonymous namespace). PR c++/106604 gcc/cp/ChangeLog: * decl.cc (wrapup_namespace_globals): Don't issue a -Wunused-function warning for a deduction guide. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/class-deduction116.C: New test. --- gcc/cp/decl.cc | 1 + gcc/testsuite/g++.dg/cpp1z/class-deduction116.C | 8 ++++++++ 2 files changed, 9 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction116.C diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 792ab330dd0..9fe3a0b98fd 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -856,6 +856,7 @@ wrapup_namespace_globals () && !TREE_PUBLIC (decl) && !DECL_ARTIFICIAL (decl) && !DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl) + && !deduction_guide_p (decl) && !warning_suppressed_p (decl, OPT_Wunused_function)) warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wunused_function, diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C new file mode 100644 index 00000000000..00f6d5fef41 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C @@ -0,0 +1,8 @@ +// PR c++/106604 +// { dg-do compile { target c++17 } } +// { dg-additional-options "-Wunused-function" } + +namespace { + template<class T> struct A { A(...); }; + A(bool) -> A<bool>; // { dg-bogus "never defined" } +} -- 2.42.0.rc0.25.ga82fb66fed ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] 2023-08-10 16:09 [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] Patrick Palka @ 2023-08-10 17:22 ` Jason Merrill 2023-08-10 20:40 ` Patrick Palka 0 siblings, 1 reply; 6+ messages in thread From: Jason Merrill @ 2023-08-10 17:22 UTC (permalink / raw) To: Patrick Palka, gcc-patches On 8/10/23 12:09, Patrick Palka wrote: > Booststrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk and perhaps 13? > > -- >8 -- > > We shouldn't issue a "declared static but never defined" warning > for a deduction guide (declared in an anonymous namespace). > > PR c++/106604 > > gcc/cp/ChangeLog: > > * decl.cc (wrapup_namespace_globals): Don't issue a > -Wunused-function warning for a deduction guide. Maybe instead of special casing this here we could set DECL_INITIAL on deduction guides so they look defined? > gcc/testsuite/ChangeLog: > > * g++.dg/cpp1z/class-deduction116.C: New test. > --- > gcc/cp/decl.cc | 1 + > gcc/testsuite/g++.dg/cpp1z/class-deduction116.C | 8 ++++++++ > 2 files changed, 9 insertions(+) > create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc > index 792ab330dd0..9fe3a0b98fd 100644 > --- a/gcc/cp/decl.cc > +++ b/gcc/cp/decl.cc > @@ -856,6 +856,7 @@ wrapup_namespace_globals () > && !TREE_PUBLIC (decl) > && !DECL_ARTIFICIAL (decl) > && !DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl) > + && !deduction_guide_p (decl) > && !warning_suppressed_p (decl, OPT_Wunused_function)) > warning_at (DECL_SOURCE_LOCATION (decl), > OPT_Wunused_function, > diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > new file mode 100644 > index 00000000000..00f6d5fef41 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > @@ -0,0 +1,8 @@ > +// PR c++/106604 > +// { dg-do compile { target c++17 } } > +// { dg-additional-options "-Wunused-function" } > + > +namespace { > + template<class T> struct A { A(...); }; > + A(bool) -> A<bool>; // { dg-bogus "never defined" } > +} ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] 2023-08-10 17:22 ` Jason Merrill @ 2023-08-10 20:40 ` Patrick Palka 2023-08-10 21:11 ` Jason Merrill 0 siblings, 1 reply; 6+ messages in thread From: Patrick Palka @ 2023-08-10 20:40 UTC (permalink / raw) To: Jason Merrill; +Cc: Patrick Palka, gcc-patches On Thu, 10 Aug 2023, Jason Merrill wrote: > On 8/10/23 12:09, Patrick Palka wrote: > > Booststrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > > trunk and perhaps 13? > > > > -- >8 -- > > > > We shouldn't issue a "declared static but never defined" warning > > for a deduction guide (declared in an anonymous namespace). > > > > PR c++/106604 > > > > gcc/cp/ChangeLog: > > > > * decl.cc (wrapup_namespace_globals): Don't issue a > > -Wunused-function warning for a deduction guide. > > Maybe instead of special casing this here we could set DECL_INITIAL on > deduction guides so they look defined? That seems to work, but it requires some tweaks in duplicate_decls to keep saying "declared" instead of "defined" when diagnosing a deduction guide redeclaration. I'm not sure which approach is preferable? -- >8 -- gcc/cp/ChangeLog: * decl.cc (duplicate_decls): When diagnosing a redeclared deduction guide, ensure we say "declared" instead of "defined". (redeclaration_error_message): Move up deduction guide tests. (grokfndecl): Set DECL_INITIAL to void_node for a deduction guide. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/class-deduction116.C: New test. --- gcc/cp/decl.cc | 23 +++++++++++-------- .../g++.dg/cpp1z/class-deduction116.C | 5 ++++ 2 files changed, 19 insertions(+), 9 deletions(-) diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 2b3fb313166..70dcff7aa8c 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -2025,7 +2025,9 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden) error_at (newdecl_loc, errmsg, newdecl); if (DECL_NAME (olddecl) != NULL_TREE) inform (olddecl_loc, - (DECL_INITIAL (olddecl) && namespace_bindings_p ()) + (DECL_INITIAL (olddecl) + && !deduction_guide_p (olddecl) + && namespace_bindings_p ()) ? G_("%q#D previously defined here") : G_("%q#D previously declared here"), olddecl); return error_mark_node; @@ -3271,6 +3273,10 @@ redeclaration_error_message (tree newdecl, tree olddecl) /* We'll complain about linkage mismatches in warn_extern_redeclared_static. */ + if (deduction_guide_p (olddecl) + && deduction_guide_p (newdecl)) + return G_("deduction guide %q+D redeclared"); + /* Defining the same name twice is no good. */ if (decl_defined_p (olddecl) && decl_defined_p (newdecl)) @@ -3298,10 +3304,6 @@ redeclaration_error_message (tree newdecl, tree olddecl) } } - if (deduction_guide_p (olddecl) - && deduction_guide_p (newdecl)) - return G_("deduction guide %q+D redeclared"); - /* [class.compare.default]: A definition of a comparison operator as defaulted that appears in a class shall be the first declaration of that function. */ @@ -3330,6 +3332,10 @@ redeclaration_error_message (tree newdecl, tree olddecl) if (DECL_TEMPLATE_RESULT (newdecl) == DECL_TEMPLATE_RESULT (olddecl)) return NULL; + if (deduction_guide_p (olddecl) + && deduction_guide_p (newdecl)) + return G_("deduction guide %q+D redeclared"); + nt = DECL_TEMPLATE_RESULT (newdecl); if (DECL_TEMPLATE_INFO (nt)) nt = DECL_TEMPLATE_RESULT (template_for_substitution (nt)); @@ -3356,10 +3362,6 @@ redeclaration_error_message (tree newdecl, tree olddecl) } } - if (deduction_guide_p (olddecl) - && deduction_guide_p (newdecl)) - return G_("deduction guide %q+D redeclared"); - /* Core issue #226 (C++11): If a friend function template declaration specifies a @@ -10353,6 +10355,9 @@ grokfndecl (tree ctype, DECL_CXX_DESTRUCTOR_P (decl) = 1; DECL_NAME (decl) = dtor_identifier; break; + case sfk_deduction_guide: + DECL_INITIAL (decl) = void_node; + break; default: break; } diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C new file mode 100644 index 00000000000..00f6d5fef41 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C @@ -0,0 +1,8 @@ +// PR c++/106604 +// { dg-do compile { target c++17 } } +// { dg-additional-options "-Wunused-function" } + +namespace { + template<class T> struct A { A(...); }; + A(bool) -> A<bool>; // { dg-bogus "never defined" } +} -- 2.42.0.rc1 > > > gcc/testsuite/ChangeLog: > > > > * g++.dg/cpp1z/class-deduction116.C: New test. > > --- > > gcc/cp/decl.cc | 1 + > > gcc/testsuite/g++.dg/cpp1z/class-deduction116.C | 8 ++++++++ > > 2 files changed, 9 insertions(+) > > create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > > > > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc > > index 792ab330dd0..9fe3a0b98fd 100644 > > --- a/gcc/cp/decl.cc > > +++ b/gcc/cp/decl.cc > > @@ -856,6 +856,7 @@ wrapup_namespace_globals () > > && !TREE_PUBLIC (decl) > > && !DECL_ARTIFICIAL (decl) > > && !DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (decl) > > + && !deduction_guide_p (decl) > > && !warning_suppressed_p (decl, OPT_Wunused_function)) > > warning_at (DECL_SOURCE_LOCATION (decl), > > OPT_Wunused_function, > > diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > > b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > > new file mode 100644 > > index 00000000000..00f6d5fef41 > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > > @@ -0,0 +1,8 @@ > > +// PR c++/106604 > > +// { dg-do compile { target c++17 } } > > +// { dg-additional-options "-Wunused-function" } > > + > > +namespace { > > + template<class T> struct A { A(...); }; > > + A(bool) -> A<bool>; // { dg-bogus "never defined" } > > +} > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] 2023-08-10 20:40 ` Patrick Palka @ 2023-08-10 21:11 ` Jason Merrill 2023-08-11 13:54 ` Patrick Palka 0 siblings, 1 reply; 6+ messages in thread From: Jason Merrill @ 2023-08-10 21:11 UTC (permalink / raw) To: Patrick Palka; +Cc: gcc-patches On 8/10/23 16:40, Patrick Palka wrote: > On Thu, 10 Aug 2023, Jason Merrill wrote: > >> On 8/10/23 12:09, Patrick Palka wrote: >>> Booststrapped and regtested on x86_64-pc-linux-gnu, does this look OK for >>> trunk and perhaps 13? >>> >>> -- >8 -- >>> >>> We shouldn't issue a "declared static but never defined" warning >>> for a deduction guide (declared in an anonymous namespace). >>> >>> PR c++/106604 >>> >>> gcc/cp/ChangeLog: >>> >>> * decl.cc (wrapup_namespace_globals): Don't issue a >>> -Wunused-function warning for a deduction guide. >> >> Maybe instead of special casing this here we could set DECL_INITIAL on >> deduction guides so they look defined? > > That seems to work, but it requires some tweaks in duplicate_decls to keep > saying "declared" instead of "defined" when diagnosing a deduction guide > redeclaration. I'm not sure which approach is preferable? I'm not sure it matters which we say; the restriction that you can't repeat a deduction guide makes it more like a definition anyway (even if [basic.def] disagrees). Is the diagnostic worse apart from that word? Jason ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] 2023-08-10 21:11 ` Jason Merrill @ 2023-08-11 13:54 ` Patrick Palka 2023-08-11 14:00 ` Jason Merrill 0 siblings, 1 reply; 6+ messages in thread From: Patrick Palka @ 2023-08-11 13:54 UTC (permalink / raw) To: Jason Merrill; +Cc: Patrick Palka, gcc-patches [-- Attachment #1: Type: text/plain, Size: 6656 bytes --] On Thu, 10 Aug 2023, Jason Merrill wrote: > On 8/10/23 16:40, Patrick Palka wrote: > > On Thu, 10 Aug 2023, Jason Merrill wrote: > > > > > On 8/10/23 12:09, Patrick Palka wrote: > > > > Booststrapped and regtested on x86_64-pc-linux-gnu, does this look OK > > > > for > > > > trunk and perhaps 13? > > > > > > > > -- >8 -- > > > > > > > > We shouldn't issue a "declared static but never defined" warning > > > > for a deduction guide (declared in an anonymous namespace). > > > > > > > > PR c++/106604 > > > > > > > > gcc/cp/ChangeLog: > > > > > > > > * decl.cc (wrapup_namespace_globals): Don't issue a > > > > -Wunused-function warning for a deduction guide. > > > > > > Maybe instead of special casing this here we could set DECL_INITIAL on > > > deduction guides so they look defined? > > > > That seems to work, but it requires some tweaks in duplicate_decls to keep > > saying "declared" instead of "defined" when diagnosing a deduction guide > > redeclaration. I'm not sure which approach is preferable? > > I'm not sure it matters which we say; the restriction that you can't repeat a > deduction guide makes it more like a definition anyway (even if [basic.def] > disagrees). Is the diagnostic worse apart from that word? Ah, makes sense. So we can also remove the special case for them in the redeclaration checking code after we give them a dummy DECL_INITIAL. Like so? Here's a before/after for the diagnostic with the below patch: Before src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:11:1: error: deduction guide ‘S()-> S<int>’ redeclared 11 | S() -> S<int>; // { dg-error "redefinition" } | ^ src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:10:1: note: ‘S()-> S<int>’ previously declared here 10 | S() -> S<int>; // { dg-message "previously defined here|old declaration" } | ^ After src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:11:1: error: redefinition of ‘S()-> S<int>’ 11 | S() -> S<int>; // { dg-error "redefinition" } | ^ src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:10:1: note: ‘S()-> S<int>’ previously defined here 10 | S() -> S<int>; // { dg-message "previously defined here|old declaration" } | ^ -- >8 -- Subject: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] Here we're unintentionally issuing a "declared static but never defined" warning for a deduction guide declared in an anonymous namespace. This patch fixes this by giving deduction guides a dummy DECL_INITIAL, which suppresses the warning and also allows us to simplify redeclaration checking for them. Co-authored-by: Jason Merrill <jason@redhat.com> PR c++/106604 gcc/cp/ChangeLog: * decl.cc (redeclaration_error_message): Remove special handling for deduction guides. (grokfndecl): Give deduction guides a dummy DECL_INITIAL. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/class-deduction74.C: Expect "defined" instead of "declared" in diagnostics for a repeated deduction guide. * g++.dg/cpp1z/class-deduction116.C: New test. --- gcc/cp/decl.cc | 14 ++++++-------- gcc/testsuite/g++.dg/cpp1z/class-deduction116.C | 8 ++++++++ gcc/testsuite/g++.dg/cpp1z/class-deduction74.C | 14 +++++++------- 3 files changed, 21 insertions(+), 15 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction116.C diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 792ab330dd0..3ada5516c58 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -3297,10 +3297,6 @@ redeclaration_error_message (tree newdecl, tree olddecl) } } - if (deduction_guide_p (olddecl) - && deduction_guide_p (newdecl)) - return G_("deduction guide %q+D redeclared"); - /* [class.compare.default]: A definition of a comparison operator as defaulted that appears in a class shall be the first declaration of that function. */ @@ -3355,10 +3351,6 @@ redeclaration_error_message (tree newdecl, tree olddecl) } } - if (deduction_guide_p (olddecl) - && deduction_guide_p (newdecl)) - return G_("deduction guide %q+D redeclared"); - /* Core issue #226 (C++11): If a friend function template declaration specifies a @@ -10352,6 +10344,12 @@ grokfndecl (tree ctype, DECL_CXX_DESTRUCTOR_P (decl) = 1; DECL_NAME (decl) = dtor_identifier; break; + case sfk_deduction_guide: + /* Give deduction guides a definition even though they don't really + have one: the restriction that you can't repeat a deduction guide + makes them more like a definition anyway. */ + DECL_INITIAL (decl) = void_node; + break; default: break; } diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C new file mode 100644 index 00000000000..00f6d5fef41 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C @@ -0,0 +1,8 @@ +// PR c++/106604 +// { dg-do compile { target c++17 } } +// { dg-additional-options "-Wunused-function" } + +namespace { + template<class T> struct A { A(...); }; + A(bool) -> A<bool>; // { dg-bogus "never defined" } +} diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C index fe113819a95..7bab882da7d 100644 --- a/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C @@ -7,20 +7,20 @@ template<typename> struct S { }; template<typename> struct X { }; -S() -> S<int>; // { dg-message "previously declared here|old declaration" } -S() -> S<int>; // { dg-error "redeclared" } +S() -> S<int>; // { dg-message "previously defined here|old declaration" } +S() -> S<int>; // { dg-error "redefinition" } X() -> X<int>; S() -> S<float>; // { dg-error "ambiguating new declaration of" } -S(bool) -> S<int>; // { dg-message "previously declared here" } -explicit S(bool) -> S<int>; // { dg-error "redeclared" } +S(bool) -> S<int>; // { dg-message "previously defined here" } +explicit S(bool) -> S<int>; // { dg-error "redefinition" } -explicit S(char) -> S<int>; // { dg-message "previously declared here" } -S(char) -> S<int>; // { dg-error "redeclared" } +explicit S(char) -> S<int>; // { dg-message "previously defined here" } +S(char) -> S<int>; // { dg-error "redefinition" } template<typename T> S(T, T) -> S<int>; // { dg-message "previously declared here" } template<typename T> X(T, T) -> X<int>; -template<typename T> S(T, T) -> S<int>; // { dg-error "redeclared" } +template<typename T> S(T, T) -> S<int>; // { dg-error "redefinition" } // OK: Use SFINAE. template<typename T> S(T) -> S<typename T::foo>; -- 2.42.0.rc1 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] 2023-08-11 13:54 ` Patrick Palka @ 2023-08-11 14:00 ` Jason Merrill 0 siblings, 0 replies; 6+ messages in thread From: Jason Merrill @ 2023-08-11 14:00 UTC (permalink / raw) To: Patrick Palka; +Cc: gcc-patches On 8/11/23 09:54, Patrick Palka wrote: > On Thu, 10 Aug 2023, Jason Merrill wrote: > >> On 8/10/23 16:40, Patrick Palka wrote: >>> On Thu, 10 Aug 2023, Jason Merrill wrote: >>> >>>> On 8/10/23 12:09, Patrick Palka wrote: >>>>> Booststrapped and regtested on x86_64-pc-linux-gnu, does this look OK >>>>> for >>>>> trunk and perhaps 13? >>>>> >>>>> -- >8 -- >>>>> >>>>> We shouldn't issue a "declared static but never defined" warning >>>>> for a deduction guide (declared in an anonymous namespace). >>>>> >>>>> PR c++/106604 >>>>> >>>>> gcc/cp/ChangeLog: >>>>> >>>>> * decl.cc (wrapup_namespace_globals): Don't issue a >>>>> -Wunused-function warning for a deduction guide. >>>> >>>> Maybe instead of special casing this here we could set DECL_INITIAL on >>>> deduction guides so they look defined? >>> >>> That seems to work, but it requires some tweaks in duplicate_decls to keep >>> saying "declared" instead of "defined" when diagnosing a deduction guide >>> redeclaration. I'm not sure which approach is preferable? >> >> I'm not sure it matters which we say; the restriction that you can't repeat a >> deduction guide makes it more like a definition anyway (even if [basic.def] >> disagrees). Is the diagnostic worse apart from that word? > > Ah, makes sense. So we can also remove the special case for them in the > redeclaration checking code after we give them a dummy DECL_INITIAL. > Like so? OK, thanks. > Here's a before/after for the diagnostic with the below patch: > > Before > > src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:11:1: error: deduction guide ‘S()-> S<int>’ redeclared > 11 | S() -> S<int>; // { dg-error "redefinition" } > | ^ > src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:10:1: note: ‘S()-> S<int>’ previously declared here > 10 | S() -> S<int>; // { dg-message "previously defined here|old declaration" } > | ^ > > After > > src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:11:1: error: redefinition of ‘S()-> S<int>’ > 11 | S() -> S<int>; // { dg-error "redefinition" } > | ^ > src/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C:10:1: note: ‘S()-> S<int>’ previously defined here > 10 | S() -> S<int>; // { dg-message "previously defined here|old declaration" } > | ^ > > -- >8 -- > > Subject: [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] > > Here we're unintentionally issuing a "declared static but never defined" > warning for a deduction guide declared in an anonymous namespace. > This patch fixes this by giving deduction guides a dummy DECL_INITIAL, > which suppresses the warning and also allows us to simplify redeclaration > checking for them. > > Co-authored-by: Jason Merrill <jason@redhat.com> > > PR c++/106604 > > gcc/cp/ChangeLog: > > * decl.cc (redeclaration_error_message): Remove special handling > for deduction guides. > (grokfndecl): Give deduction guides a dummy DECL_INITIAL. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp1z/class-deduction74.C: Expect "defined" instead > of "declared" in diagnostics for a repeated deduction guide. > * g++.dg/cpp1z/class-deduction116.C: New test. > --- > gcc/cp/decl.cc | 14 ++++++-------- > gcc/testsuite/g++.dg/cpp1z/class-deduction116.C | 8 ++++++++ > gcc/testsuite/g++.dg/cpp1z/class-deduction74.C | 14 +++++++------- > 3 files changed, 21 insertions(+), 15 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc > index 792ab330dd0..3ada5516c58 100644 > --- a/gcc/cp/decl.cc > +++ b/gcc/cp/decl.cc > @@ -3297,10 +3297,6 @@ redeclaration_error_message (tree newdecl, tree olddecl) > } > } > > - if (deduction_guide_p (olddecl) > - && deduction_guide_p (newdecl)) > - return G_("deduction guide %q+D redeclared"); > - > /* [class.compare.default]: A definition of a comparison operator as > defaulted that appears in a class shall be the first declaration of > that function. */ > @@ -3355,10 +3351,6 @@ redeclaration_error_message (tree newdecl, tree olddecl) > } > } > > - if (deduction_guide_p (olddecl) > - && deduction_guide_p (newdecl)) > - return G_("deduction guide %q+D redeclared"); > - > /* Core issue #226 (C++11): > > If a friend function template declaration specifies a > @@ -10352,6 +10344,12 @@ grokfndecl (tree ctype, > DECL_CXX_DESTRUCTOR_P (decl) = 1; > DECL_NAME (decl) = dtor_identifier; > break; > + case sfk_deduction_guide: > + /* Give deduction guides a definition even though they don't really > + have one: the restriction that you can't repeat a deduction guide > + makes them more like a definition anyway. */ > + DECL_INITIAL (decl) = void_node; > + break; > default: > break; > } > diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > new file mode 100644 > index 00000000000..00f6d5fef41 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction116.C > @@ -0,0 +1,8 @@ > +// PR c++/106604 > +// { dg-do compile { target c++17 } } > +// { dg-additional-options "-Wunused-function" } > + > +namespace { > + template<class T> struct A { A(...); }; > + A(bool) -> A<bool>; // { dg-bogus "never defined" } > +} > diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C > index fe113819a95..7bab882da7d 100644 > --- a/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C > +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction74.C > @@ -7,20 +7,20 @@ > template<typename> struct S { }; > template<typename> struct X { }; > > -S() -> S<int>; // { dg-message "previously declared here|old declaration" } > -S() -> S<int>; // { dg-error "redeclared" } > +S() -> S<int>; // { dg-message "previously defined here|old declaration" } > +S() -> S<int>; // { dg-error "redefinition" } > X() -> X<int>; > S() -> S<float>; // { dg-error "ambiguating new declaration of" } > > -S(bool) -> S<int>; // { dg-message "previously declared here" } > -explicit S(bool) -> S<int>; // { dg-error "redeclared" } > +S(bool) -> S<int>; // { dg-message "previously defined here" } > +explicit S(bool) -> S<int>; // { dg-error "redefinition" } > > -explicit S(char) -> S<int>; // { dg-message "previously declared here" } > -S(char) -> S<int>; // { dg-error "redeclared" } > +explicit S(char) -> S<int>; // { dg-message "previously defined here" } > +S(char) -> S<int>; // { dg-error "redefinition" } > > template<typename T> S(T, T) -> S<int>; // { dg-message "previously declared here" } > template<typename T> X(T, T) -> X<int>; > -template<typename T> S(T, T) -> S<int>; // { dg-error "redeclared" } > +template<typename T> S(T, T) -> S<int>; // { dg-error "redefinition" } > > // OK: Use SFINAE. > template<typename T> S(T) -> S<typename T::foo>; ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-08-11 14:00 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-08-10 16:09 [PATCH] c++: bogus warning w/ deduction guide in anon ns [PR106604] Patrick Palka 2023-08-10 17:22 ` Jason Merrill 2023-08-10 20:40 ` Patrick Palka 2023-08-10 21:11 ` Jason Merrill 2023-08-11 13:54 ` Patrick Palka 2023-08-11 14:00 ` Jason Merrill
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