Enforce that query results implement Debug

compiler/rustc_data_structures/src/stable_hasher.rs

@@ -552,6 +552,7 @@ pub fn hash_stable_hashmap<HCX, K, V, R, SK, F>(
 
 /// A vector container that makes sure that its items are hashed in a stable
 /// order.
+#[derive(Debug)]
 pub struct StableVec<T>(Vec<T>);
 
 impl<T> StableVec<T> {

compiler/rustc_data_structures/src/steal.rs

@@ -21,6 +21,7 @@ use crate::sync::{MappedReadGuard, ReadGuard, RwLock};
 /// -- once the value is stolen -- it will never be read from again.
 //
 // FIXME(#41710): what is the best way to model linear queries?
+#[derive(Debug)]
 pub struct Steal<T> {
     value: RwLock<Option<T>>,
 }