https://gcc.gnu.org/g:e36bd73d7030b3efb182821f06c48c5258809766
commit r16-9812-ge36bd73d7030b3efb182821f06c48c5258809766 Author: Marek Polacek <[email protected]> Date: Mon Oct 12 17:04:24 2026 -0400 c++/reflection: ICE with reflection and sb packs [PR126680] We mark consteval-only vars DECL_EXTERNAL, which confused the code in set_decl_context_in_fn: if (TREE_CODE (decl) == FUNCTION_DECL || (VAR_P (decl) && DECL_EXTERNAL (decl))) /* Make sure local externs are marked as such. OMP UDRs really are nested functions. */ gcc_checking_assert (DECL_LOCAL_DECL_P (decl) /*...*/ ); for code with: static constexpr auto [...a] = std::array { ^^int }; where there is no local extern. This reminded me of r17-392, and I think here we can use DECL_THIS_EXTERN. I think we shouldn't lose any relevant coverage because of this change. We set DECL_THIS_EXTERN in grokvardecl: DECL_THIS_EXTERN (decl) = 1; DECL_EXTERNAL (decl) = !initialized; and in grokdeclarator, which sets DECL_THIS_EXTERN only after grokvardecl has been called. A local extern with an initializer is rejected in grokdeclarator. So a block-scope VAR_DECL with DECL_THIS_EXTERN always has DECL_EXTERNAL set. PR c++/126680 gcc/cp/ChangeLog: * name-lookup.cc (set_decl_context_in_fn): Check DECL_THIS_EXTERN instead of DECL_EXTERNAL. gcc/testsuite/ChangeLog: * g++.dg/reflect/decomp1.C: New test. Reviewed-by: Jason Merrill <[email protected]> (cherry picked from commit eb5375341a4743fa565626a0d1ffc51f87dba577) Diff: --- gcc/cp/name-lookup.cc | 2 +- gcc/testsuite/g++.dg/reflect/decomp1.C | 17 +++++++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc index 45c2976d698b..15ab3d5095f9 100644 --- a/gcc/cp/name-lookup.cc +++ b/gcc/cp/name-lookup.cc @@ -3669,7 +3669,7 @@ static void set_decl_context_in_fn (tree ctx, tree decl) { if (TREE_CODE (decl) == FUNCTION_DECL - || (VAR_P (decl) && DECL_EXTERNAL (decl))) + || (VAR_P (decl) && DECL_THIS_EXTERN (decl))) /* Make sure local externs are marked as such. OMP UDRs really are nested functions. */ gcc_checking_assert (DECL_LOCAL_DECL_P (decl) diff --git a/gcc/testsuite/g++.dg/reflect/decomp1.C b/gcc/testsuite/g++.dg/reflect/decomp1.C new file mode 100644 index 000000000000..281affea27c1 --- /dev/null +++ b/gcc/testsuite/g++.dg/reflect/decomp1.C @@ -0,0 +1,17 @@ +// PR c++/126680 +// { dg-do compile { target c++26 } } +// { dg-additional-options "-freflection" } + +#include <array> + +template<int = 0> +void f () +{ + static constexpr auto [...a] = std::array { ^^int }; +} + +void +g () +{ + f (); +}
