fix: step scrutinee of case & can instantiate empty vec

1 files changed, 13 insertions, 2 deletions

diff --git a/src/type/check.rs b/src/type/check.rs
index f842b4c..02b629c 100644
--- a/src/type/check.rs
+++ b/src/type/check.rs
@@ -218,10 +218,10 @@ impl SExp {
     pub fn type_check(&self) -> Result<Type, TypeError> {
 	let res = self.infer_type(HashMap::new());
 	match res {
-	    Ok(res) => match res.is_concrete() {
+	    Ok(res) => {println!("maybe unbound: {}", res); match res.is_concrete() {
 		Ok(()) => Ok(res),
 		Err(name) => Err(UnboundGeneric(name)),
-	    },
+	    }},
 	    e => e,
 	}
     }
@@ -281,6 +281,17 @@ impl SExp {
 		    return scons(op.clone(), l.clone()).get_fun_type(ctx);
 		}
 
+		// Nil vector
+		if (**op).clone() == Atom(Nil) {
+		    return match (**l).clone() {
+			SCons(v, n) if *n == Atom(Nil) => match *v {
+			    Atom(Ty(t)) => Ok(vecof(t)),
+			    _ => Err(OtherError),
+			},
+			_ => Err(OtherError)
+		    }
+		}
+
 		// Case expressions
 		if let Some((scrutinee, patarms)) = scons(op.clone(), l.clone()).check_case() {
 		    let scruty = scrutinee.infer_type(ctx.clone())?;