Use then_some in meet

Author: smoelius

clippy_utils/src/ty/type_certainty/certainty.rs

@@ -27,13 +27,7 @@ impl Meet for Option<DefId> {
     fn meet(self, other: Self) -> Self {
         match (self, other) {
             (None, _) | (_, None) => None,
-            (Some(lhs), Some(rhs)) => {
-                if lhs == rhs {
-                    Some(lhs)
-                } else {
-                    None
-                }
-            },
+            (Some(lhs), Some(rhs)) => (lhs == rhs).then_some(lhs),
         }
     }
 }