Document intentional test panics

src/tests.rs

@@ -1,3 +1,8 @@
+#![expect(
+    clippy::panic,
+    reason = "panic paths and panic assertions are intentional test behavior"
+)]
+
 use super::*;
 use std::alloc::Layout;
 use std::cell::Cell;
@@ -16,10 +21,6 @@ impl DropTracker {
 }
 
 impl Drop for DropTracker {
-    #[expect(
-        clippy::panic,
-        reason = "overflow means the test's drop-count assertion can no longer be trusted"
-    )]
     fn drop(&mut self) {
         let Some(next_count) = self.counter.get().checked_add(1) else {
             panic!("drop counter overflow");
@@ -28,10 +29,6 @@ impl Drop for DropTracker {
     }
 }
 
-#[expect(
-    clippy::panic,
-    reason = "overflow means the test's capacity expectation is invalid"
-)]
 fn checked_product(left: usize, right: usize) -> usize {
     let Some(product) = left.checked_mul(right) else {
         panic!("test multiplication overflow");
@@ -86,10 +83,7 @@ fn test_debug_implementations_expose_only_metadata() {
     assert_debug_metadata(&format!("{send_erased:?}"), "SendTypeErasedVec");
 
     let send_sync_erased = SendSyncTypeErasedVec::new(vec![42_u32]);
-    assert_debug_metadata(
-        &format!("{send_sync_erased:?}"),
-        "SendSyncTypeErasedVec",
-    );
+    assert_debug_metadata(&format!("{send_sync_erased:?}"), "SendSyncTypeErasedVec");
 }
 
 #[test]