Author: yronglin Date: 2023-06-06T23:58:37+08:00 New Revision: 540294845babbb2be909ea456323d7bc8a1763df
URL: https://github.com/llvm/llvm-project/commit/540294845babbb2be909ea456323d7bc8a1763df DIFF: https://github.com/llvm/llvm-project/commit/540294845babbb2be909ea456323d7bc8a1763df.diff LOG: [Clang] Reject increment of bool value in unevaluated contexts after C++17 Clang now incorrectly allowed increment of bool in unevaluated contexts, we set `diagnostic::ext_increment_bool` to be SFINAEFailure to fix this issue. ``` template<class T> auto f(T t) -> decltype(++t); auto f(...) -> void; void g() { f(true); // Clang wrongly makes this a hard error } ``` ``` template <class T> concept can_increment = requires(T t) { ++t; }; template <class T> void f() { static_assert(requires(T t) { ++t; }); // Incorrectly allowed } int main() { f<bool>(); static_assert(!can_increment<bool>); // Incorrectly fails bool b = false; ++b; // Correctly rejected } ``` Fix issue: https://github.com/llvm/llvm-project/issues/47517 Reviewed By: erichkeane Differential Revision: https://reviews.llvm.org/D152259 Added: clang/test/SemaCXX/bool-increment-SFINAE.cpp Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/DiagnosticSemaKinds.td Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 9bbf270c27476..6f582f584bdf6 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -476,6 +476,8 @@ Bug Fixes in This Version - Fix crash when passing a braced initializer list to a parentehsized aggregate initialization expression. (`#63008 <https://github.com/llvm/llvm-project/issues/63008>`_). +- Reject increment of bool value in unevaluated contexts after C++17. + (`#47517 <https://github.com/llvm/llvm-project/issues/47517>`_). Bug Fixes to Compiler Builtins ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 90ecbd623ceef..5895888c175fa 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -7661,7 +7661,7 @@ def warn_increment_bool : Warning< "incompatible with C++17">, InGroup<DeprecatedIncrementBool>; def ext_increment_bool : ExtWarn< "ISO C++17 does not allow incrementing expression of type bool">, - DefaultError, InGroup<IncrementBool>; + DefaultError, SFINAEFailure, InGroup<IncrementBool>; def err_increment_decrement_enum : Error< "cannot %select{decrement|increment}0 expression of enum type %1">; diff --git a/clang/test/SemaCXX/bool-increment-SFINAE.cpp b/clang/test/SemaCXX/bool-increment-SFINAE.cpp new file mode 100644 index 0000000000000..d3889293fc0b6 --- /dev/null +++ b/clang/test/SemaCXX/bool-increment-SFINAE.cpp @@ -0,0 +1,37 @@ +// RUN: %clang_cc1 %std_cxx98-14 -fsyntax-only -verify=precxx17 %s +// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify=expected %s +// RUN: %clang_cc1 -std=c++17 -DFAILED_CXX17 -fsyntax-only -verify=failcxx17 %s +// RUN: %clang_cc1 %std_cxx20- -fsyntax-only -verify=cxx20 %s +// expected-no-diagnostics + +template<class T> auto f(T t) -> decltype(++t); // precxx17-warning {{incrementing expression of type bool is deprecated}} + +auto f(...) -> void; +void g() { f(true); } + +#ifdef FAILED_CXX17 + +template<class T> auto f1(T t) -> decltype(++t); // failcxx17-note {{candidate template ignored: substitution failure [with T = bool]: ISO C++17 does not allow incrementing expression of type bool}} +auto f1(void) -> void; // failcxx17-note {{candidate function not viable: requires 0 arguments, but 1 was provided}} +void g1() { f1(true); } // failcxx17-error {{no matching function for call to 'f1'}} + +#endif + +#if __cplusplus >= 202002L +template <class T> +concept can_increment = requires(T t) { + ++t; +}; + +template <class T> +void f() { + static_assert(requires(T t) { ++t; }); // cxx20-error {{static assertion failed due to requirement 'requires (bool t) { <<error-expression>>; }'}} +} + +int main() { + f<bool>(); // cxx20-note {{in instantiation of function template specialization 'f<bool>' requested here}} + static_assert(!can_increment<bool>); + + return 0; +} +#endif _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits