Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/16?
-- >8 --
In this test in the template for the
std::println("{}", static_cast<int>(s.[:member:]));
line provokes a bogus "consteval-only expressions are only allowed
in a constant-evaluated context" error. (Not the line before
because there we have an OVERLOAD because the second argument's
type isn't obvious, and so the whole thing is considered type-dep.)
A splice-specifier is [: constant-expression :], and [expr.const.defns]:
an expression or conversion is manifestly constant-evaluated if it is
a constant-expression.
So I think we shouldn't walk SPLICE_EXPRs in
check_out_of_consteval_use_r.
PR c++/125900
gcc/cp/ChangeLog:
* reflect.cc (check_out_of_consteval_use_r): Don't walk
SPLICE_EXPR.
gcc/testsuite/ChangeLog:
* g++.dg/reflect/expr18.C: New test.
---
gcc/cp/reflect.cc | 4 ++++
gcc/testsuite/g++.dg/reflect/expr18.C | 25 +++++++++++++++++++++++++
2 files changed, 29 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/reflect/expr18.C
diff --git a/gcc/cp/reflect.cc b/gcc/cp/reflect.cc
index 3d6d24eb23a..73e160d700f 100644
--- a/gcc/cp/reflect.cc
+++ b/gcc/cp/reflect.cc
@@ -8760,6 +8760,10 @@ check_out_of_consteval_use_r (tree *tp, int
*walk_subtrees, void *pset)
|| TREE_CODE (t) == DECL_EXPR
/* Neither into USING_STMT. */
|| TREE_CODE (t) == USING_STMT
+ /* The operand of a splice is a constant-expression, thus
+ manifestly constant-evaluated, so consteval-only types are permitted
+ here. */
+ || TREE_CODE (t) == SPLICE_EXPR
/* Blocks can appear in the TREE_VEC operand of OpenMP
depend/affinity/map/to/from OMP_CLAUSEs when using iterators. */
|| TREE_CODE (t) == BLOCK)
diff --git a/gcc/testsuite/g++.dg/reflect/expr18.C
b/gcc/testsuite/g++.dg/reflect/expr18.C
new file mode 100644
index 00000000000..f2ceefc6f88
--- /dev/null
+++ b/gcc/testsuite/g++.dg/reflect/expr18.C
@@ -0,0 +1,25 @@
+// PR c++/125900
+// { dg-do compile { target c++26 } }
+// { dg-additional-options "-freflection" }
+
+#include <meta>
+#include <print>
+
+struct S {
+ float f;
+};
+
+int main() {
+ S s{.f = 1.5f};
+
+ constexpr auto member{^^S::f};
+ std::println("{}", s.[:member:]);
+ std::println("{}", static_cast<int>(s.[:member:]));
+
+ constexpr auto access_context{std::meta::access_context::current()};
+ template for (constexpr auto member :
+ std::define_static_array(nonstatic_data_members_of(^^S,
access_context))) {
+ std::println("{}", s.[:member:]);
+ std::println("{}", static_cast<int>(s.[:member:]));
+ }
+}
base-commit: fdffb66e398d4440116a7d7834aae11053973ffe
--
2.54.0
