cleaned up excluded_extensions

src/parameters.rs

@@ -147,21 +147,20 @@ impl Parameters {
 		let mut excluded = vec![];
 		if let Some(exclude) = self.exclude.as_ref() {
 			// add extensions excluded by `-x`
-			excluded.append(&mut exclude.iter().map(|ext| ext.as_str()).collect());
+			excluded.extend(exclude.iter().map(|ext| ext.as_str()));
 		}
 
 		if let Some(exclude_set) = &self.exclude_set {
 			// add extensions excluded by `-X`
-			excluded.append(&mut exclude_set.extensions());
+			excluded.extend_from_slice(&exclude_set.extensions());
 		}
 
-		if excluded.is_empty() {
+		match excluded {
 			// no extensions to exclude - return none
-			None
+			x if x.is_empty() => None,
-		} else {
 			// excluded doesn't sound like a word anymore
 			// tongue twister: enter X-options' excellent extension exclusion
-			Some(excluded)
+			x => Some(x)
 		}
 	}