Apply #[cfg(debug_assertions)] directly

Author: aerooneqq

compiler/rustc_hir/src/definitions.rs

@@ -407,13 +407,11 @@ impl Definitions {
         // Find the next free disambiguator for this key.
         let disambiguator = {
             #[cfg(debug_assertions)]
-            {
-                debug_assert_eq!(
-                    parent,
-                    disambiguator.parent.expect("must be set"),
-                    "provided parent and parent in disambiguator must be the same"
-                )
-            }
+            debug_assert_eq!(
+                parent,
+                disambiguator.parent.expect("must be set"),
+                "provided parent and parent in disambiguator must be the same"
+            );
 
             let next_disamb = disambiguator.next.entry(data).or_insert(0);
             let disambiguator = *next_disamb;