From 92ea98da2f89348c3dfdc7d49594a4d876d06ba2 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 18 Mar 2019 05:27:17 +0100
Subject: Split List literal between empty and non-empty

---
 dhall/src/typecheck.rs | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

(limited to 'dhall/src/typecheck.rs')

diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index 26ab360..387327a 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -351,15 +351,16 @@ where
             }
             return Ok(ty);
         }
-        ListLit(t, xs) => {
+        EmptyListLit(t) => {
+            let s = normalized_type_with(ctx, t.clone())?;
+            ensure_is_type(s, InvalidListType(t.clone()))?;
+            let t = normalize(Rc::clone(t));
+            return Ok(dhall_expr!(List t));
+        }
+        NEListLit(xs) => {
             let mut iter = xs.iter().enumerate();
-            let t: Rc<Expr<_, _>> = match t {
-                Some(t) => t.clone(),
-                None => {
-                    let (_, first_x) = iter.next().unwrap();
-                    type_with(ctx, first_x.clone())?
-                }
-            };
+            let (_, first_x) = iter.next().unwrap();
+            let t = type_with(ctx, first_x.clone())?;
 
             let s = normalized_type_with(ctx, t.clone())?;
             ensure_is_type(s, InvalidListType(t.clone()))?;
-- 
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