From af31db6461110dfb81efaf2a287327226ae5a7a8 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Mon, 11 Aug 2025 08:53:26 +0200 Subject: c++: Fix structured binding redeclaration error recovery [PR121442] My C++26 P2686R4 PR117784 caused ICE on the following testcase. While the earlier conditions guarantee decl2 is not error_mark_node, decl can be (that is used when something erroneous has been seen earlier and the whole structured bindings will be ignored after parsing). So, the following patch avoids the copying of constexpr/constinit flags if decl is error_mark_node. 2025-08-11 Jakub Jelinek PR c++/121442 * parser.cc (cp_parser_decomposition_declaration): Don't copy DECL_DECLARED_CONST{EXPR,INIT}_P bits from decl to decl2 if decl is error_mark_node. * g++.dg/cpp1z/decomp65.C: New test. --- gcc/cp/parser.cc | 9 +++++++-- gcc/testsuite/g++.dg/cpp1z/decomp65.C | 13 +++++++++++++ 2 files changed, 20 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1z/decomp65.C (limited to 'gcc') diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 743fd74..1dbe35b 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -17002,8 +17002,13 @@ cp_parser_decomposition_declaration (cp_parser *parser, else { prev = decl2; - DECL_DECLARED_CONSTEXPR_P (decl2) = DECL_DECLARED_CONSTEXPR_P (decl); - DECL_DECLARED_CONSTINIT_P (decl2) = DECL_DECLARED_CONSTINIT_P (decl); + if (decl != error_mark_node) + { + DECL_DECLARED_CONSTEXPR_P (decl2) + = DECL_DECLARED_CONSTEXPR_P (decl); + DECL_DECLARED_CONSTINIT_P (decl2) + = DECL_DECLARED_CONSTINIT_P (decl); + } if (j == (unsigned) pack) { tree dtype = cxx_make_type (DECLTYPE_TYPE); diff --git a/gcc/testsuite/g++.dg/cpp1z/decomp65.C b/gcc/testsuite/g++.dg/cpp1z/decomp65.C new file mode 100644 index 0000000..5dd8eff --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/decomp65.C @@ -0,0 +1,13 @@ +// PR c++/121442 +// { dg-do compile { target c++11 } } +// { dg-options "" } + +struct S { int a, b, c, d, e; }; + +void +foo () +{ + auto [a, b, b, b, c ] = S {}; // { dg-warning "structured bindings only available with" "" { target c++14_down } } + // { dg-error "redeclaration of 'auto b'" "" { target *-*-* } .-1 } + // { dg-message "'auto b' previously declared here" "" { target *-*-* } .-2 } +} -- cgit v1.1