fstring_concurrent_set_create: only assert the string has no ivars

The NEWOBJ tracepoint can generate an object_id, that's alright,
what we don't want is actual instance variables.

1 files changed, 1 insertions, 1 deletions

diff --git a/string.c b/string.c
index 56c83ca2d5..0370fc5d1e 100644
--- a/string.c
+++ b/string.c
@@ -549,7 +549,7 @@ fstring_concurrent_set_create(VALUE str, void *data)
     RUBY_ASSERT(RB_TYPE_P(str, T_STRING));
     RUBY_ASSERT(OBJ_FROZEN(str));
     RUBY_ASSERT(!FL_TEST_RAW(str, STR_FAKESTR));
-    RUBY_ASSERT(!rb_obj_gen_fields_p(str));
+    RUBY_ASSERT(!rb_shape_obj_has_ivars(str));
     RUBY_ASSERT(RBASIC_CLASS(str) == rb_cString);
     RUBY_ASSERT(!rb_objspace_garbage_object_p(str));