From 6fa2a56a5cd01d7c5be0ab3495a633914be28559 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Wed, 4 Mar 2020 16:38:18 +0100
Subject: [PATCH] Fix doulbe Attr wrapping in List.getUnsafe

---
 src/unique_builtins.rs         |  5 +----
 tests/test_uniqueness_infer.rs | 12 ++++++++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/unique_builtins.rs b/src/unique_builtins.rs
index 6a01e968eb..ae23945b13 100644
--- a/src/unique_builtins.rs
+++ b/src/unique_builtins.rs
@@ -451,10 +451,7 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
 
     add_type(
         Symbol::LIST_GET_UNSAFE,
-        unique_function(
-            vec![list_type(UVAR1, TVAR1), int_type(UVAR2)],
-            attr_type(UVAR3, TVAR1),
-        ),
+        unique_function(vec![list_type(UVAR1, TVAR1), int_type(UVAR2)], flex(TVAR1)),
     );
 
     // set : Attr (w | u | v) (List (Attr u a))
diff --git a/tests/test_uniqueness_infer.rs b/tests/test_uniqueness_infer.rs
index 831652fae0..b6e7a760f2 100644
--- a/tests/test_uniqueness_infer.rs
+++ b/tests/test_uniqueness_infer.rs
@@ -2087,4 +2087,16 @@ mod test_infer_uniq {
             "Attr * (Attr * (List (Attr (a | b) c)) -> Attr (* | a | b) (List (Attr a c)))",
         );
     }
+
+    #[test]
+    fn set_then_get() {
+        infer_eq(
+            indoc!(
+                r#"
+            List.getUnsafe (List.set [ 12, 9, 7, 3 ] 1 42) 1
+                "#
+            ),
+            "Attr * Int",
+        );
+    }
 }