================ @@ -9966,8 +9966,13 @@ AssignConvertType Sema::CheckSingleAssignmentConstraints(QualType LHSType, // If there is a conversion of some kind, check to see what kind of // pointer conversion happened so we can diagnose a C++ compatibility // diagnostic if the conversion is invalid. This only matters if the RHS - // is some kind of void pointer. - if (Kind != CK_NoOp && !getLangOpts().CPlusPlus) { + // is some kind of void pointer. We have a carve-out when the RHS is from + // a macro expansion because the use of a macro may indicate different + // code between C and C++. Consider: char *s = NULL; where NULL is + // defined as (void *)0 in C (which would be invalid in C++), but 0 in + // C++, which is valid in C++. + if (Kind != CK_NoOp && !getLangOpts().CPlusPlus && + !RHS.get()->getBeginLoc().isMacroID()) { ---------------- AaronBallman wrote:
That's kind of the point -- this code is specific to the case of a void pointer conversion from a null pointer constant. So we do get the pattern, pass that predicate and get to the point of saying "cool, time to diagnose this implicit void * cast" and now we're saying "oh, but the RHS is a macro so nevermind, just be quiet about it because the macro may expand differently in C++ than it did in C". https://github.com/llvm/llvm-project/pull/140724 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits