aaronpuchert added a comment. Yeah, we should get this over the line. I'm still not quite sure where to put the check. Reading @rsmith's comment again, SemaInit might perhaps be acceptable for now, except that I should add the additional tests (in case we don't have them already).
I think we also need D113837 <https://reviews.llvm.org/D113837>, because otherwise `void` is being used as a placeholder. In any event, I should at least rebase the patches and check if they still work. ================ Comment at: clang/lib/Sema/SemaInit.cpp:1311-1319 + } else if (DeclType->isVoidType()) { + // [expr.type.conv]p2: Otherwise, if the type is cv void and the + // initializer is () or {} (after pack expansion, if any), the expression + // is a prvalue of type void that performs no initialization. + if (IList->getNumInits() > 0) { + if (!VerifyOnly) + SemaRef.Diag(IList->getBeginLoc(), diag::err_init_list_void_nonempty); ---------------- rsmith wrote: > Hm, this seems like the wrong place for this check, given the wording -- the > language rule is specific to functional casts, and shouldn't apply to > initialization of `void`-typed objects in general -- but perhaps it's the > best place we have (and I think we deal with the `void()` case here in > SemaInit too). Please at least make sure that we still properly reject things > like: > ``` > void f() { > return {}; > } > ``` > We also need to decide whether to accept the compound-literal form of this: > ``` > void g() { > (void){}; > } > ``` > GCC trunk does, but I'm not sure whether that's intentional or an oversight. > We certainly shouldn't accept that (without a diagnostic, at least) in C. > Hm, this seems like the wrong place for this check, given the wording -- the > language rule is specific to functional casts, and shouldn't apply to > initialization of `void`-typed objects in general -- but perhaps it's the > best place we have (and I think we deal with the `void()` case here in > SemaInit too). So we should unconditionally allow it here and check later in `CastOperation::CheckCXXCStyleCast`? It handles `void` target types already, but only for [expr.static.cast]p6: > Any expression can be explicitly converted to type cv void, in which case it > becomes a discarded-value expression ([expr.prop]). Indeed we don't create a `CXXFunctionalCastExpr` for `void()` but a `CXXScalarValueInitExpr` (though probably for legacy reasons). But it should be the proper place, I agree. > Please at least make sure that we still properly reject things like: > ``` > void f() { > return {}; > } > ``` That fails as before with ``` <stdin>:2:3: error: void function 'f' must not return a value return {}; ^ ~~ ``` > We also need to decide whether to accept the compound-literal form of this: > ``` > void g() { > (void){}; > } > ``` That is rejected in C and C++ with ``` <stdin>:2:3: error: variable has incomplete type 'void' (void){}; ^~~~~~~~ ``` Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D113838/new/ https://reviews.llvm.org/D113838 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
