c++: Don't check for consteval-only uses inside of USING_STMT [PR125184]

I think a USING_STMT operand shouldn't count as consteval-only use.

2026-05-07  Jakub Jelinek  <jakub@redhat.com>

	PR c++/125184
	* reflect.cc (check_out_of_consteval_use_r): Don't walk children of
	USING_STMTs.

	* g++.dg/reflect/using3.C: New test.

Reviewed-by: Jason Merrill <jason@redhat.com>

diff --git a/gcc/cp/reflect.cc b/gcc/cp/reflect.cc
index bcbb5980c9f31abffb0d9dde3dedd23206109773..0f8daf55d0a6d0c4b196e7293cbfa7e5da628c11 100644 (file)
--- a/gcc/cp/reflect.cc
+++ b/gcc/cp/reflect.cc
@@ -8716,6 +8716,8 @@ check_out_of_consteval_use_r (tree *tp, int *walk_subtrees, void *pset)
       || TREE_CODE (t) == INIT_EXPR
       /* And don't recurse on DECL_EXPRs.  */
       || TREE_CODE (t) == DECL_EXPR
+      /* Neither into USING_STMT.  */
+      || TREE_CODE (t) == USING_STMT
       /* 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/using3.C b/gcc/testsuite/g++.dg/reflect/using3.C
new file mode 100644 (file)
index 0000000..03b0b0a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/reflect/using3.C
@@ -0,0 +1,11 @@
+// PR c++/125184
+// { dg-do compile { target c++26 } }
+// { dg-additional-options "-freflection" }
+
+#include <meta>
+
+void
+foo ()
+{
+  using std::meta::info;
+}