https://gcc.gnu.org/g:6441bc34bcd4cc558d79710a87c2ab47085a8712
commit r16-7692-g6441bc34bcd4cc558d79710a87c2ab47085a8712 Author: Marek Polacek <[email protected]> Date: Thu Feb 19 12:40:39 2026 -0500 c++/reflection: also walk BIND_EXPR_BODY As discussed in <https://gcc.gnu.org/pipermail/gcc-patches/2026-January/705756.html>, we shouldn't walk BIND_EXPR_VARS in check_out_of_consteval_use_r, but BIND_EXPR_BODY should still be walked. The IF_STMT is there so that we don't emit bogus errors in "if consteval" branches, as tested in expr12.C. gcc/cp/ChangeLog: * reflect.cc (check_out_of_consteval_use_r): Walk BIND_EXPR_BODY. For IF_STMT_CONSTEVAL_P, only walk the ELSE_CLAUSE. For IF_STMT_CONSTEXPR_P, only walk the THEN_ and ELSE_CLAUSE. gcc/testsuite/ChangeLog: * g++.dg/reflect/expr11.C: Test more if constexpr. * g++.dg/reflect/expr12.C: Adjust test. Reviewed-by: Jason Merrill <[email protected]> Diff: --- gcc/cp/reflect.cc | 42 +++++++++++++++++++++++++++++++++-- gcc/testsuite/g++.dg/reflect/expr11.C | 17 ++++++++++++++ gcc/testsuite/g++.dg/reflect/expr12.C | 18 +++++++++++++++ 3 files changed, 75 insertions(+), 2 deletions(-) diff --git a/gcc/cp/reflect.cc b/gcc/cp/reflect.cc index 5254ac028d1b..3c82251f511b 100644 --- a/gcc/cp/reflect.cc +++ b/gcc/cp/reflect.cc @@ -8120,8 +8120,6 @@ check_out_of_consteval_use_r (tree *tp, int *walk_subtrees, void *pset) /* Don't walk INIT_EXPRs, because we'd emit bogus errors about member initializers. */ || TREE_CODE (t) == INIT_EXPR - /* Don't walk BIND_EXPR_VARS. */ - || TREE_CODE (t) == BIND_EXPR /* And don't recurse on DECL_EXPRs. */ || TREE_CODE (t) == DECL_EXPR) { @@ -8151,6 +8149,46 @@ check_out_of_consteval_use_r (tree *tp, int *walk_subtrees, void *pset) return ret; } + if (TREE_CODE (t) == BIND_EXPR) + { + if (tree r = cp_walk_tree (&BIND_EXPR_BODY (t), + check_out_of_consteval_use_r, pset, + static_cast<hash_set<tree> *>(pset))) + return r; + /* Don't walk BIND_EXPR_VARS. */ + *walk_subtrees = false; + return NULL_TREE; + } + + if (TREE_CODE (t) == IF_STMT) + { + if (IF_STMT_CONSTEVAL_P (t)) + { + if (tree r = cp_walk_tree (&ELSE_CLAUSE (t), + check_out_of_consteval_use_r, pset, + static_cast<hash_set<tree> *>(pset))) + return r; + /* Don't walk the consteval branch. */ + *walk_subtrees = false; + return NULL_TREE; + } + else if (IF_STMT_CONSTEXPR_P (t)) + { + if (tree r = cp_walk_tree (&THEN_CLAUSE (t), + check_out_of_consteval_use_r, pset, + static_cast<hash_set<tree> *>(pset))) + return r; + if (tree r = cp_walk_tree (&ELSE_CLAUSE (t), + check_out_of_consteval_use_r, pset, + static_cast<hash_set<tree> *>(pset))) + return r; + /* Don't walk the condition -- it's a manifestly constant-evaluated + context. */ + *walk_subtrees = false; + return NULL_TREE; + } + } + /* Now check the type to see if we are dealing with a consteval-only expression. */ if (!consteval_only_p (t)) diff --git a/gcc/testsuite/g++.dg/reflect/expr11.C b/gcc/testsuite/g++.dg/reflect/expr11.C index 20af4bc07ae0..44d66947d9d6 100644 --- a/gcc/testsuite/g++.dg/reflect/expr11.C +++ b/gcc/testsuite/g++.dg/reflect/expr11.C @@ -29,4 +29,21 @@ f () while (^^char != ^^char); do {} while (^^char != ^^char); } + + if constexpr (true) + { + auto r = ^^int; // { dg-error "consteval-only variable .r." } + } + else + { + auto r = ^^int; // { dg-error "consteval-only variable .r." } + } + if constexpr (false) + { + auto r = ^^int; // { dg-error "consteval-only variable .r." } + } + else + { + auto r = ^^int; // { dg-error "consteval-only variable .r." } + } } diff --git a/gcc/testsuite/g++.dg/reflect/expr12.C b/gcc/testsuite/g++.dg/reflect/expr12.C index a59a60f03a38..34aed536429c 100644 --- a/gcc/testsuite/g++.dg/reflect/expr12.C +++ b/gcc/testsuite/g++.dg/reflect/expr12.C @@ -20,11 +20,29 @@ f () if not consteval { ^^void; // { dg-error "consteval-only expressions" } + } + if not consteval + { q; // { dg-error "consteval-only expressions" } + } + if not consteval + { auto r = ^^int; // { dg-error "consteval-only variable" } + } + if not consteval + { if (q != ^^char); // { dg-error "consteval-only expressions" } + } + if not consteval + { if (^^char == ^^char); // { dg-error "consteval-only expressions" } + } + if not consteval + { while (^^char != ^^char); // { dg-error "consteval-only expressions" } + } + if not consteval + { do {} while (^^char != ^^char); // { dg-error "consteval-only expressions" } } }
