diff --git a/src/rust/src/parser.rs b/src/rust/src/parser.rs
index 19b67d3c3..ac461c8ee 100644
--- a/src/rust/src/parser.rs
+++ b/src/rust/src/parser.rs
@@ -426,7 +426,7 @@ impl CcxOptions {
             }
         }
 
-        self.num_input_files = self.num_input_files + 1;
+        self.num_input_files += 1;
 
         0
     }
diff --git a/src/rust/src/utils.rs b/src/rust/src/utils.rs
index 17f09326c..cb37ad979 100644
--- a/src/rust/src/utils.rs
+++ b/src/rust/src/utils.rs
@@ -20,6 +20,8 @@ pub unsafe fn string_to_c_char(a: &str) -> *mut ::std::os::raw::c_char {
     s.into_raw()
 }
 
+/// # Safety
+/// The pointer returned has to be deallocated using from_raw() at some point
 pub unsafe fn string_null() -> *mut c_char {
     std::ptr::null_mut()
 }