https://github.com/localspook created https://github.com/llvm/llvm-project/pull/196889
[CWG988](https://wg21.link/cwg988) specifies that reference collapsing is performed when trying to form a reference to a `decltype`. Clang implements this since 2.7: https://godbolt.org/z/vYzKbv8x7 (and I checked a few versions after that to make sure there were no regressions). >From e711e6b6f658bedea1fc59f88ec734d788e490d9 Mon Sep 17 00:00:00 2001 From: Victor Chernyakin <[email protected]> Date: Sun, 10 May 2026 23:46:06 -0700 Subject: [PATCH] [clang][NFC] Mark CWG988 as implemented and add a test --- clang/test/CXX/drs/cwg9xx.cpp | 15 +++++++++++++++ clang/www/cxx_dr_status.html | 2 +- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/clang/test/CXX/drs/cwg9xx.cpp b/clang/test/CXX/drs/cwg9xx.cpp index c8fdca3a45c3e..a0c659cfc643a 100644 --- a/clang/test/CXX/drs/cwg9xx.cpp +++ b/clang/test/CXX/drs/cwg9xx.cpp @@ -169,6 +169,21 @@ enum struct E4 : int { e = static_cast<int>(E4()) }; #endif } // namespace cwg977 +namespace cwg988 { // cwg988: 2.7 +#if __cplusplus >= 201103L +void f() { + int i; + int& lvalue_ref = i; + int&& rvalue_ref = static_cast<int&&>(i); + + static_assert(__is_same(decltype(lvalue_ref)&, int&), ""); + static_assert(__is_same(decltype(lvalue_ref)&&, int&), ""); + static_assert(__is_same(decltype(rvalue_ref)&, int&), ""); + static_assert(__is_same(decltype(rvalue_ref)&&, int&&), ""); +} +#endif +} // namespace cwg988 + namespace cwg990 { // cwg990: 3.5 #if __cplusplus >= 201103L struct A { // #cwg990-A diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html index feef0c3770f64..add0c344b5f18 100755 --- a/clang/www/cxx_dr_status.html +++ b/clang/www/cxx_dr_status.html @@ -6693,7 +6693,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2> <td>[<a href="https://wg21.link/dcl.type.simple";>dcl.type.simple</a>]</td> <td>CD2</td> <td>Reference-to-reference collapsing with <TT>decltype</TT></td> - <td class="unknown" align="center">Unknown</td> + <td class="full" align="center">Clang 2.7</td> </tr> <tr id="989"> <td><a href="https://cplusplus.github.io/CWG/issues/989.html";>989</a></td> _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
