This test ICEs in C++23 because we reach the new code in do_auto_deduction:
30468 if (cxx_dialect >= cxx23 30469 && context == adc_return_type 30470 && (!AUTO_IS_DECLTYPE (auto_node) 30471 || !unparenthesized_id_or_class_member_access_p (init)) 30472 && (r = treat_lvalue_as_rvalue_p (maybe_undo_parenthesized_ref (init), 30473 /*return*/true))) where 'init' is "VIEW_CONVERT_EXPR<<<< error >>>>(y)", and then the move in treat_lvalue_as_rvalue_p returns error_mark_node whereupon set_implicit_rvalue_p crashes. I don't think such V_C_Es are useful so let's not create them. But that won't fix the ICE so I'm checking the return value of move. A structured bindings decl can have an error type, that is set in cp_finish_decomp: 8908 TREE_TYPE (first) = error_mark_node; therefore I think treat_lvalue_as_rvalue_p just needs to cope. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? PR c++/107276 gcc/cp/ChangeLog: * typeck.cc (treat_lvalue_as_rvalue_p): Check the return value of move. gcc/ChangeLog: * tree.cc (maybe_wrap_with_location): Don't create a location wrapper when the type is erroneous. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/decomp4.C: New test. --- gcc/cp/typeck.cc | 7 ++++++- gcc/testsuite/g++.dg/cpp2a/decomp4.C | 8 ++++++++ gcc/tree.cc | 3 ++- 3 files changed, 16 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/decomp4.C diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc index 16e7d85793d..5ca191759f6 100644 --- a/gcc/cp/typeck.cc +++ b/gcc/cp/typeck.cc @@ -10726,7 +10726,12 @@ treat_lvalue_as_rvalue_p (tree expr, bool return_p) if (DECL_CONTEXT (retval) != current_function_decl) return NULL_TREE; if (return_p) - return set_implicit_rvalue_p (move (expr)); + { + expr = move (expr); + if (expr == error_mark_node) + return NULL_TREE; + return set_implicit_rvalue_p (expr); + } /* if the operand of a throw-expression is a (possibly parenthesized) id-expression that names an implicitly movable entity whose scope does not diff --git a/gcc/testsuite/g++.dg/cpp2a/decomp4.C b/gcc/testsuite/g++.dg/cpp2a/decomp4.C new file mode 100644 index 00000000000..28b3f172b53 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/decomp4.C @@ -0,0 +1,8 @@ +// PR c++/107276 +// { dg-do run { target c++20 } } + +auto f(auto x) { + auto [y] = x; // { dg-error "cannot decompose" } + return y; +} +int i = f(0); diff --git a/gcc/tree.cc b/gcc/tree.cc index 81a6ceaf181..4e5b1df4d85 100644 --- a/gcc/tree.cc +++ b/gcc/tree.cc @@ -14352,7 +14352,8 @@ maybe_wrap_with_location (tree expr, location_t loc) /* For now, don't add wrappers to exceptional tree nodes, to minimize any impact of the wrapper nodes. */ - if (EXCEPTIONAL_CLASS_P (expr)) + if (EXCEPTIONAL_CLASS_P (expr) + || (TREE_TYPE (expr) && EXCEPTIONAL_CLASS_P (TREE_TYPE (expr)))) return expr; /* Compiler-generated temporary variables don't need a wrapper. */ base-commit: d155442de043c1bef7d27cf2d6be4eba618afcb9 -- 2.37.3