Ping. On Mon, May 11, 2020 at 04:23:17PM -0400, Marek Polacek via Gcc-patches wrote: > On Sun, Apr 05, 2020 at 09:46:09PM -0400, Jason Merrill wrote: > > On 4/4/20 7:30 PM, Marek Polacek wrote: > > > This patch implements DR 2237 which says that a simple-template-id is > > > no longer valid as the declarator-id of a constructor or destructor; > > > see <https://eel.is/c++draft/diff.cpp17.class#2>. It is not explicitly > > > stated but out-of-line destructors with a simple-template-id are also > > > meant to be ill-formed now. (Out-of-line constructors like that are > > > invalid since DR1435 I think.) This change only applies to C++20; it > > > is not a DR against C++17. > > > > > > I'm not crazy about the diagnostic in constructors but ISTM that > > > cp_parser_constructor_declarator_p shouldn't print errors. > > > > > > Does it seem reasonable to apply this now or should I defer to GCC 11? > > > > A new error should wait for GCC 11. > > Coming back to this now that we're again in stage 1. > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > > > > > 2020-04-04 Marek Polacek <pola...@redhat.com> > > > > > > DR 2237 > > > * parser.c (cp_parser_unqualified_id): Reject simple-template-id as > > > the declarator-id of a destructor. > > > (cp_parser_constructor_declarator_p): Reject simple-template-id as > > > the declarator-id of a constructor. > > > > > > * g++.dg/DRs/dr2237.C: New test. > > > * g++.dg/parse/constructor2.C: Add dg-error for C++20. > > > * g++.dg/parse/dtor12.C: Likewise. > > > * g++.dg/parse/dtor4.C: Likewise. > > > * g++.dg/template/dtor4.C: Adjust dg-error. > > > * g++.dg/template/error34.C: Likewise. > > > * g++.old-deja/g++.other/inline15.C: Only run for C++17 and lesses. > > > * g++.old-deja/g++.pt/ctor2.C: Add dg-error for C++20. > > > --- > > > gcc/cp/parser.c | 16 ++++++++++++++++ > > > gcc/testsuite/g++.dg/DRs/dr2237.C | 18 ++++++++++++++++++ > > > gcc/testsuite/g++.dg/parse/constructor2.C | 4 ++-- > > > gcc/testsuite/g++.dg/parse/dtor12.C | 2 +- > > > gcc/testsuite/g++.dg/parse/dtor4.C | 2 +- > > > gcc/testsuite/g++.dg/template/dtor4.C | 2 +- > > > gcc/testsuite/g++.dg/template/error34.C | 10 +++++----- > > > .../g++.old-deja/g++.other/inline15.C | 2 +- > > > gcc/testsuite/g++.old-deja/g++.pt/ctor2.C | 2 +- > > > 9 files changed, 46 insertions(+), 12 deletions(-) > > > create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237.C > > > > > > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > > > index 7e5921e039f..810edfa87a9 100644 > > > --- a/gcc/cp/parser.c > > > +++ b/gcc/cp/parser.c > > > @@ -6114,6 +6114,16 @@ cp_parser_unqualified_id (cp_parser* parser, > > > return build_min_nt_loc (loc, BIT_NOT_EXPR, make_auto ()); > > > } > > > + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the > > > + declarator-id of a constructor or destructor. */ > > > + if (token->type == CPP_TEMPLATE_ID && cxx_dialect >= cxx2a) > > > + { > > > + if (!cp_parser_uncommitted_to_tentative_parse_p (parser)) > > > + error_at (tilde_loc, "template-id not allowed for destructor"); > > > + cp_parser_simulate_error (parser); > > > > The usual pattern is > > > > if (!cp_parser_simulate_error (parser)) > > error... > > Fixed. > > > > + return error_mark_node; > > > + } > > > + > > > /* If there was an explicit qualification (S::~T), first look > > > in the scope given by the qualification (i.e., S). > > > @@ -28675,6 +28685,12 @@ cp_parser_constructor_declarator_p (cp_parser > > > *parser, cp_parser_flags flags, > > > if (!constructor_name_p (id, nested_name_specifier)) > > > constructor_p = false; > > > } > > > + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the > > > + declarator-id of a constructor or destructor. */ > > > + else if (constructor_p > > > + && cxx_dialect >= cxx2a > > > + && cp_lexer_next_token_is (parser->lexer, CPP_TEMPLATE_ID)) > > > + constructor_p = false; > > > /* If we still think that this might be a constructor-declarator, > > > look for a class-name. */ > > > else if (constructor_p) > > > > Do you also want to exclude CPP_TEMPLATE_ID from the test at the top of the > > function for C++20? > > In fact we can get away with only excluding CPP_TEMPLATE_ID in C++20 there, > because for e.g. X<T>::X<T>(); we'll give the "names the constructor, not the > type" error, so we won't even get here. > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > -- >8 -- > This patch implements DR 2237 which says that a simple-template-id is > no longer valid as the declarator-id of a constructor or destructor; > see [diff.cpp17.class]#2. It is not explicitly stated but out-of-line > destructors with a simple-template-id are also meant to be ill-formed > now. (Out-of-line constructors like that are invalid since DR1435 I > think.) This change only applies to C++20; it is not a DR against C++17. > > I'm not crazy about the diagnostic in constructors but ISTM that > cp_parser_constructor_declarator_p shouldn't print errors. > > DR 2237 > * parser.c (cp_parser_unqualified_id): Reject simple-template-id as > the declarator-id of a destructor. > (cp_parser_constructor_declarator_p): Reject simple-template-id as > the declarator-id of a constructor. > > * g++.dg/DRs/dr2237.C: New test. > * g++.dg/parse/constructor2.C: Add dg-error for C++20. > * g++.dg/parse/dtor12.C: Likewise. > * g++.dg/parse/dtor4.C: Likewise. > * g++.dg/template/dtor4.C: Adjust dg-error. > * g++.dg/template/error34.C: Likewise. > * g++.old-deja/g++.other/inline15.C: Only run for C++17 and lesses. > * g++.old-deja/g++.pt/ctor2.C: Add dg-error for C++20. > --- > gcc/cp/parser.c | 13 ++++++++++++- > gcc/testsuite/g++.dg/DRs/dr2237.C | 18 ++++++++++++++++++ > gcc/testsuite/g++.dg/parse/constructor2.C | 4 ++-- > gcc/testsuite/g++.dg/parse/dtor12.C | 2 +- > gcc/testsuite/g++.dg/parse/dtor4.C | 2 +- > gcc/testsuite/g++.dg/template/dtor4.C | 2 +- > gcc/testsuite/g++.dg/template/error34.C | 10 +++++----- > .../g++.old-deja/g++.other/inline15.C | 2 +- > gcc/testsuite/g++.old-deja/g++.pt/ctor2.C | 2 +- > 9 files changed, 42 insertions(+), 13 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237.C > > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index 591f44f4934..593c45b5888 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -6114,6 +6114,15 @@ cp_parser_unqualified_id (cp_parser* parser, > return build_min_nt_loc (loc, BIT_NOT_EXPR, make_auto ()); > } > > + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the > + declarator-id of a constructor or destructor. */ > + if (token->type == CPP_TEMPLATE_ID && cxx_dialect >= cxx2a) > + { > + if (!cp_parser_simulate_error (parser)) > + error_at (tilde_loc, "template-id not allowed for destructor"); > + return error_mark_node; > + } > + > /* If there was an explicit qualification (S::~T), first look > in the scope given by the qualification (i.e., S). > > @@ -28636,7 +28645,9 @@ cp_parser_constructor_declarator_p (cp_parser > *parser, cp_parser_flags flags, > if (next_token->type != CPP_NAME > && next_token->type != CPP_SCOPE > && next_token->type != CPP_NESTED_NAME_SPECIFIER > - && next_token->type != CPP_TEMPLATE_ID) > + /* DR 2237 (C++20 only): A simple-template-id is no longer valid as the > + declarator-id of a constructor or destructor. */ > + && (next_token->type != CPP_TEMPLATE_ID || cxx_dialect >= cxx2a)) > return false; > > /* Parse tentatively; we are going to roll back all of the tokens > diff --git a/gcc/testsuite/g++.dg/DRs/dr2237.C > b/gcc/testsuite/g++.dg/DRs/dr2237.C > new file mode 100644 > index 00000000000..17abdf179c1 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/DRs/dr2237.C > @@ -0,0 +1,18 @@ > +// DR 2237 - Can a template-id name a constructor? > + > +template<class T> > +struct X { > + X<T>(); // { dg-error "expected" "" { target c++2a } } > + X(int); // OK, injected-class-name used > + ~X<T>(); // { dg-error "template-id not allowed for destructor" "" { > target c++2a } } > +}; > + > +// ill-formed since DR1435 > +template<typename T> X<T>::X<T>() {} // { dg-error "names the constructor|as > no template constructors" } > +template<typename T> X<T>::~X<T>() {} // { dg-error "template-id not allowed > for destructor" "" { target c++2a } } > + > +struct Q { > + // ill-formed since DR1435 > + template<typename T> friend X<T>::X<T>(); // { dg-error "names the > constructor|as no template constructors" } > + template<typename T> friend X<T>::~X<T>(); // { dg-error "template-id not > allowed for destructor" "" { target c++2a } } > +}; > diff --git a/gcc/testsuite/g++.dg/parse/constructor2.C > b/gcc/testsuite/g++.dg/parse/constructor2.C > index e514e9397e9..87007e9c715 100644 > --- a/gcc/testsuite/g++.dg/parse/constructor2.C > +++ b/gcc/testsuite/g++.dg/parse/constructor2.C > @@ -5,7 +5,7 @@ class T > { > public: > T(short,short f=0) {} > - T<TClass>(int f) {} > - T<TClass>(int f=0,const char* b=0) {} > + T<TClass>(int f) {} // { dg-error "expected" "" { target c++2a } } > + T<TClass>(int f=0,const char* b=0) {} // { dg-error "expected" "" { target > c++2a } } > }; > > diff --git a/gcc/testsuite/g++.dg/parse/dtor12.C > b/gcc/testsuite/g++.dg/parse/dtor12.C > index 1acdfa36b69..d758d3e861d 100644 > --- a/gcc/testsuite/g++.dg/parse/dtor12.C > +++ b/gcc/testsuite/g++.dg/parse/dtor12.C > @@ -2,5 +2,5 @@ > > template <class T> class a > { > - ~a<T>(); > + ~a<T>(); // { dg-error "template-id not allowed for destructor" "" { > target c++2a } } > }; > diff --git a/gcc/testsuite/g++.dg/parse/dtor4.C > b/gcc/testsuite/g++.dg/parse/dtor4.C > index 729ee2fa130..1059c189eff 100644 > --- a/gcc/testsuite/g++.dg/parse/dtor4.C > +++ b/gcc/testsuite/g++.dg/parse/dtor4.C > @@ -7,4 +7,4 @@ template <int N> struct X { > }; > > template <int N> > -X<N>::~X<N>(){} > +X<N>::~X<N>(){} // { dg-error "template-id not allowed for destructor" "" { > target c++2a } } > diff --git a/gcc/testsuite/g++.dg/template/dtor4.C > b/gcc/testsuite/g++.dg/template/dtor4.C > index 4f277b248bd..917681fc13e 100644 > --- a/gcc/testsuite/g++.dg/template/dtor4.C > +++ b/gcc/testsuite/g++.dg/template/dtor4.C > @@ -5,5 +5,5 @@ > > template<int> struct A > { > - ~A<0>(); // { dg-error "parse error|declaration" } > + ~A<0>(); // { dg-error "parse error|declaration|template-id" } > }; > diff --git a/gcc/testsuite/g++.dg/template/error34.C > b/gcc/testsuite/g++.dg/template/error34.C > index d0cbcaef28e..ab688d9ba8c 100644 > --- a/gcc/testsuite/g++.dg/template/error34.C > +++ b/gcc/testsuite/g++.dg/template/error34.C > @@ -3,27 +3,27 @@ > > template<typename T> struct A > { > - A<__builtin_offsetof(T, x)>(); // { dg-error "type/value > mismatch|offsetof\\(T, x\\)" } > + A<__builtin_offsetof(T, x)>(); // { dg-error "type/value > mismatch|offsetof\\(T, x\\)|expected" } > }; > > template<typename T> struct B > { > - B<__builtin_offsetof(T, x.y)>(); // { dg-error "type/value > mismatch|offsetof\\(T, x.y\\)" } > + B<__builtin_offsetof(T, x.y)>(); // { dg-error "type/value > mismatch|offsetof\\(T, x.y\\)|expected" } > }; > > template<typename T> struct C > { > - C<__builtin_offsetof(T, x[6])>(); // { dg-error "type/value > mismatch|offsetof\\(T, x\\\[6\\\]\\)" } > + C<__builtin_offsetof(T, x[6])>(); // { dg-error "type/value > mismatch|offsetof\\(T, x\\\[6\\\]\\)|expected" } > }; > > template<typename T> struct D > { > - D<__builtin_offsetof(T, x.y[6].z)>(); // { dg-error "type/value > mismatch|offsetof\\(T, x.y\\\[6\\\].z\\)" } > + D<__builtin_offsetof(T, x.y[6].z)>(); // { dg-error "type/value > mismatch|offsetof\\(T, x.y\\\[6\\\].z\\)|expected" } > }; > > struct E { int x; }; > > template<typename T> struct F > { > - F<__builtin_offsetof(E, x)>(); // { dg-error "type/value > mismatch|offsetof\\(E, x\\)" } > + F<__builtin_offsetof(E, x)>(); // { dg-error "type/value > mismatch|offsetof\\(E, x\\)|expected" } > }; > diff --git a/gcc/testsuite/g++.old-deja/g++.other/inline15.C > b/gcc/testsuite/g++.old-deja/g++.other/inline15.C > index 43f7f5e3025..a31c60960a5 100644 > --- a/gcc/testsuite/g++.old-deja/g++.other/inline15.C > +++ b/gcc/testsuite/g++.old-deja/g++.other/inline15.C > @@ -1,4 +1,4 @@ > -// { dg-do assemble } > +// { dg-do assemble { target c++17_down } } > // { dg-options "-O1" } > // Origin: Jakub Jelinek <ja...@redhat.com> > > diff --git a/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C > b/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C > index a8be91ddbb9..4159c84ff56 100644 > --- a/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C > +++ b/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C > @@ -4,7 +4,7 @@ > > template <class T> > struct A { > - A<T>(); > + A<T>(); // { dg-error "expected" "" { target c++2a } } > }; > > template <class T> > > base-commit: 2b2d298ff845ab7a07ffbd51da79473736da3324 > -- > Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA >
Marek
