From 4b38d56dbac6742b038551a36ec80200313123a1 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Sat, 4 Apr 2020 18:09:53 -0400 Subject: [PATCH] c++: C++20 DR 2237, disallow simple-template-id in cdtor. This patch implements DR 2237 which says that a simple-template-id is no longer valid as the declarator-id of a constructor or destructor; see [diff.cpp17.class]#2.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/ChangeLog | 8 ++++++++ gcc/cp/parser.c | 13 ++++++++++++- gcc/testsuite/ChangeLog | 12 ++++++++++++ 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 +- 11 files changed, 62 insertions(+), 13 deletions(-) create mode 100644 gcc/testsuite/g++.dg/DRs/dr2237.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 9ed4c58b403..cfe5cf00366 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,11 @@ +2020-05-20 Marek Polacek + + 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. + 2020-05-20 Marek Polacek DR 2289 diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index a6a5d975af3..a8082d39aca 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -6108,6 +6108,15 @@ 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 >= cxx20) + { + 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). @@ -28628,7 +28637,9 @@ 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 >= cxx20)) return false; /* Parse tentatively; we are going to roll back all of the tokens diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 9e437af7452..e9d334d3aef 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,15 @@ +2020-05-20 Marek Polacek + + DR 2237 + * 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. + 2020-05-20 Marek Polacek DR 2289 diff --git a/gcc/testsuite/g++.dg/DRs/dr2237.C b/gcc/testsuite/g++.dg/DRs/dr2237.C new file mode 100644 index 00000000000..f3d6d11e61e --- /dev/null +++ b/gcc/testsuite/g++.dg/DRs/dr2237.C @@ -0,0 +1,18 @@ +// DR 2237 - Can a template-id name a constructor? + +template +struct X { + X(); // { dg-error "expected" "" { target c++20 } } + X(int); // OK, injected-class-name used + ~X(); // { dg-error "template-id not allowed for destructor" "" { target c++20 } } +}; + +// ill-formed since DR1435 +template X::X() {} // { dg-error "names the constructor|as no template constructors" } +template X::~X() {} // { dg-error "template-id not allowed for destructor" "" { target c++20 } } + +struct Q { + // ill-formed since DR1435 + template friend X::X(); // { dg-error "names the constructor|as no template constructors" } + template friend X::~X(); // { dg-error "template-id not allowed for destructor" "" { target c++20 } } +}; diff --git a/gcc/testsuite/g++.dg/parse/constructor2.C b/gcc/testsuite/g++.dg/parse/constructor2.C index e514e9397e9..d620f41e027 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(int f) {} - T(int f=0,const char* b=0) {} + T(int f) {} // { dg-error "expected" "" { target c++20 } } + T(int f=0,const char* b=0) {} // { dg-error "expected" "" { target c++20 } } }; diff --git a/gcc/testsuite/g++.dg/parse/dtor12.C b/gcc/testsuite/g++.dg/parse/dtor12.C index 1acdfa36b69..dda7388192b 100644 --- a/gcc/testsuite/g++.dg/parse/dtor12.C +++ b/gcc/testsuite/g++.dg/parse/dtor12.C @@ -2,5 +2,5 @@ template class a { - ~a(); + ~a(); // { dg-error "template-id not allowed for destructor" "" { target c++20 } } }; diff --git a/gcc/testsuite/g++.dg/parse/dtor4.C b/gcc/testsuite/g++.dg/parse/dtor4.C index 729ee2fa130..1a1a8458745 100644 --- a/gcc/testsuite/g++.dg/parse/dtor4.C +++ b/gcc/testsuite/g++.dg/parse/dtor4.C @@ -7,4 +7,4 @@ template struct X { }; template -X::~X(){} +X::~X(){} // { dg-error "template-id not allowed for destructor" "" { target c++20 } } 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 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 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 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 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 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 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 diff --git a/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C b/gcc/testsuite/g++.old-deja/g++.pt/ctor2.C index a8be91ddbb9..bf418ba48c7 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 struct A { - A(); + A(); // { dg-error "expected" "" { target c++20 } } }; template -- 2.30.2