--- a/crates/jrsonnet-cli/src/lib.rs
+++ b/crates/jrsonnet-cli/src/lib.rs
@@ -51,7 +51,7 @@
 	/// Any not found `imported` file will be searched in these.
 	/// This can also be specified via `JSONNET_PATH` variable,
 	/// which should contain a colon-separated (semicolon-separated on Windows) list of directories.
-	#[clap(long, short = 'J')]
+	#[clap(long, short = 'J', multiple_occurrences = true)]
 	jpath: Vec<PathBuf>,
 }
 impl ConfigureState for MiscOpts {
--- a/crates/jrsonnet-parser/src/lib.rs
+++ b/crates/jrsonnet-parser/src/lib.rs
@@ -62,7 +62,7 @@
 				let mut defaults_started = false;
 				for param in &params {
 					defaults_started = defaults_started || param.1.is_some();
-					assert_eq!(defaults_started, param.1.is_some(), "defauld parameters should be used after all positionals");
+					assert_eq!(defaults_started, param.1.is_some(), "defauld parameters should be used after all positionals. Misplaced default parameter: {:?}", param.0);
 				}
 				expr::ParamsDesc(Rc::new(params))
 			}