| Summary: | [DR2351] Failure to compile void{} | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Gabriel Ravier <gabravier> |
| Component: | c++ | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | gabravier, jakub, Mark_B53, mpolacek, webrown.cpp |
| Priority: | P3 | Keywords: | rejects-valid |
| Version: | 12.0 | ||
| Target Milestone: | 12.0 | ||
| See Also: | https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106863 | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | 2021-10-18 00:00:00 | |
| Bug Depends on: | |||
| Bug Blocks: | 94404 | ||
| Attachments: | gcc12-pr102820.patch | ||
Confirmed. Created attachment 51638 [details] gcc12-pr102820.patch Untested fix. The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>: https://gcc.gnu.org/g:eca767aa51d1f69614222ceb130ca6bb07713232 commit r12-4782-geca767aa51d1f69614222ceb130ca6bb07713232 Author: Jakub Jelinek <jakub@redhat.com> Date: Fri Oct 29 09:28:32 2021 +0200 c++: Implement DR2351 - void{} [PR102820] Here is an implementation of DR2351 - void{} - where void{} after pack expansion is considered valid and the same thing as void(). For templates, if CONSTRUCTOR_NELTS is 0, the CONSTRUCTOR is not dependent and we can return void_node right away, if it is dependent and contains only packs, then it is potentially zero element and so we need to build CONSTRUCTOR_IS_DEPENDENT CONSTRUCTOR, while if it contains any non-pack elts, we can diagnose it right away. 2021-10-29 Jakub Jelinek <jakub@redhat.com> PR c++/102820 * semantics.c (maybe_zero_constructor_nelts): New function. (finish_compound_literal): Implement DR2351 - void{}. If type is cv void and compound_literal has no elements, return void_node. If type is cv void and compound_literal might have no elements after expansion, handle it like other dependent compound literals. * g++.dg/cpp0x/dr2351.C: New test. Implemented now. *** Bug 108591 has been marked as a duplicate of this bug. *** |
void f() { void{}; } This has been considered valid since http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#2351 was accepted as a DR in 2018, but GCC fails to compile it, with this error: <source>: In function 'void f()': <source>:3:10: error: compound literal of non-object type 'void' 3 | void{}; | ^