diff --git a/crates/ailang-core/tests/design_index_pin.rs b/crates/ailang-core/tests/design_index_pin.rs
index 3a8a282..7a49d86 100644
--- a/crates/ailang-core/tests/design_index_pin.rs
+++ b/crates/ailang-core/tests/design_index_pin.rs
@@ -229,7 +229,7 @@ fn contracts_carry_no_decision_record_prose() {
         if line.contains("**Status: ") { return Some("**Status:"); }
         if line.contains("21.g") { return Some("21.g"); }
         if let Some(s) = line.find(" sketch") {
-            let pre = line[..s].as_bytes();
+            let pre = &line.as_bytes()[..s];
             if pre.last().is_some_and(u8::is_ascii_alphanumeric)
                 && pre.iter().rev()
                       .take_while(|c| c.is_ascii_alphanumeric())