Author: Krystian Stasiowski Date: 2024-04-11T11:23:24-04:00 New Revision: 198ffb85314f7741ed048de67d68ca83bb30e16e
URL: https://github.com/llvm/llvm-project/commit/198ffb85314f7741ed048de67d68ca83bb30e16e DIFF: https://github.com/llvm/llvm-project/commit/198ffb85314f7741ed048de67d68ca83bb30e16e.diff LOG: [Clang][Sema] Implement approved resolution for CWG2858 (#88042) The approved resolution for CWG2858 changes [expr.prim.id.qual] p2 sentence 2 to read: > A declarative _nested-name-specifier_ shall not have a _computed-type-specifier_. This patch implements the approved resolution. Since we don't consider _nested-name-specifiers_ in friend declarations to be declarative (yet), it currently isn't possible to write a test that would produce this diagnostic (`diagnoseQualifiedDeclaration` is never called if the `DeclContext` can't be computed). Nevertheless, tests were added which will produce the diagnostic once we start calling `diagnoseQualifiedDeclaration` for friend declarations. Added: Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/SemaDecl.cpp clang/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp clang/test/CXX/drs/dr28xx.cpp clang/test/Parser/cxx-class.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index c4a4893aec5cd6..93318871fa9f6e 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -147,6 +147,9 @@ Resolutions to C++ Defect Reports compatibility of two types. (`CWG2759: [[no_unique_address] and common initial sequence <https://cplusplus.github.io/CWG/issues/2759.html>`_). +- Clang now diagnoses declarative nested-name-specifiers with pack-index-specifiers. + (`CWG2858: Declarative nested-name-specifiers and pack-index-specifiers <https://cplusplus.github.io/CWG/issues/2858.html>`_). + C Language Changes ------------------ diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 059a8f58da5db1..180e913155d67c 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -2402,10 +2402,6 @@ def err_selected_explicit_constructor : Error< def note_explicit_ctor_deduction_guide_here : Note< "explicit %select{constructor|deduction guide}0 declared here">; -// C++11 decltype -def err_decltype_in_declarator : Error< - "'decltype' cannot be used to name a declaration">; - // C++11 auto def warn_cxx98_compat_auto_type_specifier : Warning< "'auto' type specifier is incompatible with C++98">, @@ -8313,6 +8309,9 @@ def ext_template_after_declarative_nns : ExtWarn< def ext_alias_template_in_declarative_nns : ExtWarn< "a declarative nested name specifier cannot name an alias template">, InGroup<DiagGroup<"alias-template-in-declaration-name">>; +def err_computed_type_in_declarative_nns : Error< + "a %select{pack indexing|'decltype'}0 specifier cannot be used in " + "a declarative nested name specifier">; def err_no_typeid_with_fno_rtti : Error< "use of typeid requires -frtti">; diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index 5a23179dfbbf44..a4699d6ba2c735 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -6335,16 +6335,15 @@ bool Sema::diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC, if (TST->isDependentType() && TST->isTypeAlias()) Diag(Loc, diag::ext_alias_template_in_declarative_nns) << SpecLoc.getLocalSourceRange(); - } else if (T->isDecltypeType()) { + } else if (T->isDecltypeType() || T->getAsAdjusted<PackIndexingType>()) { // C++23 [expr.prim.id.qual]p2: // [...] A declarative nested-name-specifier shall not have a - // decltype-specifier. + // computed-type-specifier. // - // FIXME: This wording appears to be defective as it does not forbid - // declarative nested-name-specifiers with pack-index-specifiers. - // See https://github.com/cplusplus/CWG/issues/499. - Diag(Loc, diag::err_decltype_in_declarator) - << SpecLoc.getTypeLoc().getSourceRange(); + // CWG2858 changed this from 'decltype-specifier' to + // 'computed-type-specifier'. + Diag(Loc, diag::err_computed_type_in_declarative_nns) + << T->isDecltypeType() << SpecLoc.getTypeLoc().getSourceRange(); } } } while ((SpecLoc = SpecLoc.getPrefix())); diff --git a/clang/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp b/clang/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp index fbe9c0895aeae8..13be079a40bc35 100644 --- a/clang/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp +++ b/clang/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp @@ -6,8 +6,8 @@ class foo { void func(); }; -int decltype(foo())::i; // expected-error{{'decltype' cannot be used to name a declaration}} -void decltype(foo())::func() { // expected-error{{'decltype' cannot be used to name a declaration}} +int decltype(foo())::i; // expected-error{{a 'decltype' specifier cannot be used in a declarative nested name specifier}} +void decltype(foo())::func() { // expected-error{{a 'decltype' specifier cannot be used in a declarative nested name specifier}} } diff --git a/clang/test/CXX/drs/dr28xx.cpp b/clang/test/CXX/drs/dr28xx.cpp index 7f72003d66f1e3..9b21d3410a0499 100644 --- a/clang/test/CXX/drs/dr28xx.cpp +++ b/clang/test/CXX/drs/dr28xx.cpp @@ -58,3 +58,26 @@ void B<int>::g() requires true; #endif } // namespace dr2847 + +namespace dr2858 { // dr2858: 19 + +#if __cplusplus > 202302L + +template<typename... Ts> +struct A { + // FIXME: The nested-name-specifier in the following friend declarations are declarative, + // but we don't treat them as such (yet). + friend void Ts...[0]::f(); + template<typename U> + friend void Ts...[0]::g(); + + friend struct Ts...[0]::B; + // FIXME: The index of the pack-index-specifier is printed as a memory address in the diagnostic. + template<typename U> + friend struct Ts...[0]::C; + // expected-warning-re@-1 {{dependent nested name specifier 'Ts...[{{.*}}]::' for friend template declaration is not supported; ignoring this friend declaration}} +}; + +#endif + +} // namespace dr2858 diff --git a/clang/test/Parser/cxx-class.cpp b/clang/test/Parser/cxx-class.cpp index 046d2dd580f02d..c90c7e030a8bd5 100644 --- a/clang/test/Parser/cxx-class.cpp +++ b/clang/test/Parser/cxx-class.cpp @@ -59,14 +59,14 @@ typedef union { } y; } bug3177; -// check that we don't consume the token after the access specifier +// check that we don't consume the token after the access specifier // when it's not a colon class D { public // expected-error{{expected ':'}} int i; }; -// consume the token after the access specifier if it's a semicolon +// consume the token after the access specifier if it's a semicolon // that was meant to be a colon class E { public; // expected-error{{expected ':'}} @@ -281,7 +281,7 @@ struct A {} ::PR41192::a; // ok, no missing ';' here expected-warning {{extra q #if __cplusplus >= 201103L struct C; struct D { static C c; }; -struct C {} decltype(D())::c; // expected-error {{'decltype' cannot be used to name a declaration}} +struct C {} decltype(D())::c; // expected-error {{a 'decltype' specifier cannot be used in a declarative nested name specifier}} #endif } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits