Fine tune Engine size.

src/eval/data_check.rs

@@ -205,9 +205,13 @@ impl Engine {
         }
 
         // Report progress
-        self.progress
-            .as_ref()
-            .and_then(|p| p(global.num_operations))
-            .map_or(Ok(()), |token| Err(ERR::ErrorTerminated(token, pos).into()))
+        if let Some(ref progress) = self.progress {
+            match progress(global.num_operations) {
+                None => Ok(()),
+                Some(token) => Err(ERR::ErrorTerminated(token, pos).into()),
+            }
+        } else {
+            Ok(())
+        }
     }
 }

src/eval/debugger.rs

@@ -510,7 +510,7 @@ impl Engine {
             let src = global.source_raw().cloned();
             let src = src.as_ref().map(|s| s.as_str());
             let context = EvalContext::new(self, global, caches, scope, this_ptr);
-            let (.., ref on_debugger) = **x;
+            let (.., ref on_debugger) = *x;
 
             let command = on_debugger(context, event, node, src, node.position());