fix how free is called

somehow the previous version compiles passes llvm verification, but hangs when free is actually called

compiler/gen/src/llvm/refcounting.rs

@@ -331,7 +331,6 @@ pub fn build_dec_list<'a, 'ctx, 'env>(
     let call = env
         .builder
         .build_call(function, &[original_wrapper.into()], "decrement_union");
-
     call.set_call_convention(FAST_CALL_CONV);
 }
 
@@ -414,8 +413,7 @@ fn build_dec_list_help<'a, 'ctx, 'env>(
     {
         builder.position_at_end(then_block);
         if !env.leak {
-            let free = builder.build_free(refcount_ptr);
+            builder.build_free(refcount_ptr);
-            builder.insert_instruction(&free, None);
         }
         builder.build_unconditional_branch(cont_block);
     }

compiler/gen/tests/gen_list.rs

@@ -592,6 +592,15 @@ mod gen_list {
         );
     }
 
+    #[test]
+    fn list_concat_two_bigger_non_empty_lists() {
+        assert_evals_to!(
+            "List.concat [ 1.1, 2.2 ] [ 3.3, 4.4, 5.5 ]",
+            &[1.1, 2.2, 3.3, 4.4, 5.5],
+            &'static [f64]
+        );
+    }
+
     fn assert_concat_worked(num_elems1: i64, num_elems2: i64) {
         let vec1: Vec<i64> = (0..num_elems1)
             .map(|i| 12345 % (i + num_elems1 + num_elems2 + 1))

compiler/mono/tests/test_mono.rs

@@ -1920,36 +1920,4 @@ mod test_mono {
             ),
         )
     }
-
-    #[test]
-    fn linked_list_map() {
-        compiles_to_ir(
-            indoc!(
-                r#"
-                LinkedList a : [ Nil, Cons a (LinkedList a) ]
-
-                three : LinkedList Int
-                three = Cons 3 (Cons 2 (Cons 1 Nil)) 
-
-                sum : LinkedList a -> Int
-                sum = \list ->
-                    when list is
-                        Nil -> 0
-                        Cons x rest -> x + sum rest
-
-                map : (a -> b), LinkedList a -> LinkedList b
-                map = \f, list ->
-                    when list is
-                        Nil -> Nil
-                        Cons x rest -> Cons (f x) (map f rest)
-
-                sum (map (\_ -> 1) three)
-                "#
-            ),
-            indoc!(
-                r#"
-                "#
-            ),
-        )
-    }
 }