Author: Nouman Amir Date: 2023-10-03T15:06:08-04:00 New Revision: af16a4e131c1383c1b023f9384f0d73a3d207a2f
URL: https://github.com/llvm/llvm-project/commit/af16a4e131c1383c1b023f9384f0d73a3d207a2f DIFF: https://github.com/llvm/llvm-project/commit/af16a4e131c1383c1b023f9384f0d73a3d207a2f.diff LOG: Improve error message for constexpr constructors of virtual base classes The changes are for better diagnostic/error-messages. The error message of Clang, MSVC, and GCC were compared and MSVC gives more detailed error message so that is used now. Fixes https://github.com/llvm/llvm-project/issues/64843 Differential Revision: https://reviews.llvm.org/D158540 Added: Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/SemaDeclCXX.cpp clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index f5825e15c76f1da..f81fb27ec57320f 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -216,6 +216,9 @@ Improvements to Clang's diagnostics - The fix-it emitted by ``-Wformat`` for scoped enumerations now take the enumeration's underlying type into account instead of suggesting a type just based on the format string specifier being used. +- Clang now displays an improved diagnostic and a note when a defaulted special + member is marked ``constexpr`` in a class with a virtual base class + (`#64843: <https://github.com/llvm/llvm-project/issues/64843>`_). Bug Fixes in This Version ------------------------- diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index ac854a86a2fce23..e2eaeb885e2ea77 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -9454,6 +9454,8 @@ def err_defaulted_copy_assign_not_ref : Error< def err_incorrect_defaulted_constexpr : Error< "defaulted definition of %sub{select_special_member_kind}0 " "is not constexpr">; +def err_incorrect_defaulted_constexpr_with_vb: Error< + "%sub{select_special_member_kind}0 cannot be 'constexpr' in a class with virtual base class">; def err_incorrect_defaulted_consteval : Error< "defaulted declaration of %sub{select_special_member_kind}0 " "cannot be consteval because implicit definition is not constexpr">; diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index 0a48d3311d5156c..7ebb38ec2ec0c49 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -7819,10 +7819,17 @@ bool Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD, : isa<CXXConstructorDecl>(MD))) && MD->isConstexpr() && !Constexpr && MD->getTemplatedKind() == FunctionDecl::TK_NonTemplate) { - Diag(MD->getBeginLoc(), MD->isConsteval() - ? diag::err_incorrect_defaulted_consteval - : diag::err_incorrect_defaulted_constexpr) - << CSM; + if (!MD->isConsteval() && RD->getNumVBases()) { + Diag(MD->getBeginLoc(), diag::err_incorrect_defaulted_constexpr_with_vb) + << CSM; + for (const auto &I : RD->vbases()) + Diag(I.getBeginLoc(), diag::note_constexpr_virtual_base_here); + } else { + Diag(MD->getBeginLoc(), MD->isConsteval() + ? diag::err_incorrect_defaulted_consteval + : diag::err_incorrect_defaulted_constexpr) + << CSM; + } // FIXME: Explain why the special member can't be constexpr. HadError = true; } diff --git a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp index d545f49fa5db3d6..6214ff8006d67f3 100644 --- a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp +++ b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp @@ -283,3 +283,12 @@ namespace std_example { return r; } } + +struct Base { + constexpr Base() = default; +}; +struct Derived : virtual Base { // expected-note 3{{virtual base class declared here}} + constexpr Derived() = default; // expected-error {{default constructor cannot be 'constexpr' in a class with virtual base class}} + constexpr Derived(const Derived&) = default; // expected-error {{copy constructor cannot be 'constexpr' in a class with virtual base class}} + constexpr Derived(Derived&&) = default; // expected-error {{move constructor cannot be 'constexpr' in a class with virtual base class}} +}; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
