Display mld parsing error

src/vn.rs

@@ -469,7 +469,10 @@ fn load_multilinear(mlc_path: Option<&Path>, mld_path: &Path) -> Option<NamedMul
         }
     }
 
-    parser.parse(File::open(mld_path).ok()?, &[]).ok()?;
+    if let Err(e) = parser.parse(File::open(mld_path).ok()?, &[]) {
+        eprintln!("Error parsing multilinear definition: {e}");
+        return None;
+    }
 
     Some(parser.into_info())
 }