aaron.ballman added a comment. In D135287#3837617 <https://reviews.llvm.org/D135287#3837617>, @erichkeane wrote:
> In D135287#3837584 <https://reviews.llvm.org/D135287#3837584>, @jrtc27 wrote: > >> What about `__typeof__(*p)`? > > Yes, that would also be an error in C++, as it is on all other compilers. This actually relates to a use case I brought up in the RFC -- in an unevaluated context where the expression is only used to determine a type, it doesn't seem particularly harmful to allow the dereference. There might be generic programming cases where this comes up for people who exclusively use Clang, but I'm not 100% certain. ================ Comment at: clang/docs/ReleaseNotes.rst:89-98 +- Clang now diagnoses a Warning-As-Default-Error on indirection of void* in C++ + mode for ISO C++, GCC, ICC, and MSVC Compatibility. This is also now a SFINAE + error so constraint checking and SFINAE checking can be compatible with other + compilers. It is likely that this will be made a permanent error in Clang 17. + + .. code-block:: c + ---------------- Wordsmithing ================ Comment at: clang/include/clang/Basic/DiagnosticSemaKinds.td:6934-6935 "indirection requires pointer operand (%0 invalid)">; def ext_typecheck_indirection_through_void_pointer : ExtWarn< "ISO %select{C|C++}0 does not allow indirection on operand of type %1">, InGroup<DiagGroup<"void-ptr-dereference">>; ---------------- We no longer use this diagnostic in C++, so might as well simplify it. ================ Comment at: clang/include/clang/Basic/DiagnosticSemaKinds.td:6939-6942 + // Note: This uses a different diagnostics group than the C diagnostic + // so that projects that have disabled the above will get this diagnostic, + // and be aware of the deprecation. + InGroup<DiagGroup<"void-ptr-dereference-cpp">>, ---------------- Based on the code search for people using that diagnostic flag, I don't think we need to do this -- it seems like only a very small number of projects disable that warning (at least from a code search on sourcegraph). We still need a separate diagnostic (because of the `DefaultError`, but I think we can re-use the old diagnostic group. WDYT? ================ Comment at: clang/include/clang/Basic/DiagnosticSemaKinds.td:6942-6944 + InGroup<DiagGroup<"void-ptr-dereference-cpp">>, + DefaultError, + SFINAEFailure; ---------------- ================ Comment at: clang/test/SemaCXX/disallow_void_deref.cpp:1 +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s + ---------------- You should also add a RUN line showing the behavior when the diagnostic is not an error and is disabled entirely. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D135287/new/ https://reviews.llvm.org/D135287 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
