diff --git a/rs/idl-parser/src/ffi/ast/mod.rs b/rs/idl-parser/src/ffi/ast/mod.rs
index 127ef2d5..b7530e29 100644
--- a/rs/idl-parser/src/ffi/ast/mod.rs
+++ b/rs/idl-parser/src/ffi/ast/mod.rs
@@ -81,7 +81,7 @@ pub unsafe extern "C" fn free_parse_result(result: *mut ParseResult) {
     unsafe {
         let result = Box::from_raw(result);
         if result.error.code != ErrorCode::Ok {
-            let details = CString::from_raw(result.error.details as *mut i8);
+            let details = CString::from_raw(result.error.details as _);
             drop(details);
         }
     }