more use of format! variable capture

Co-authored-by: Joe ST <joe@fbstj.net>

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -357,7 +357,7 @@ impl fmt::Display for UndefinedBehaviorInfo<'_> {
                 write!(f, "{msg}null pointer is not a valid pointer")
             }
             DanglingIntPointer(i, msg) => {
-                write!(f, "{msg}{:#x} is not a valid pointer", i)
+                write!(f, "{msg}{i:#x} is not a valid pointer")
             }
             AlignmentCheckFailed { required, has } => write!(
                 f,

compiler/rustc_middle/src/mir/interpret/mod.rs

@@ -466,7 +466,7 @@ impl<'tcx> TyCtxt<'tcx> {
             return alloc_id;
         }
         let id = alloc_map.reserve();
-        debug!("creating alloc {:?} with id {:?}", alloc, id);
+        debug!("creating alloc {alloc:?} with id {id:?}");
         alloc_map.alloc_map.insert(id, alloc.clone());
         alloc_map.dedup.insert(alloc, id);
         id