diff --git a/compiler/gen_llvm/src/llvm/build_list.rs b/compiler/gen_llvm/src/llvm/build_list.rs
index 483a07755b..ede3e6430a 100644
--- a/compiler/gen_llvm/src/llvm/build_list.rs
+++ b/compiler/gen_llvm/src/llvm/build_list.rs
@@ -340,7 +340,6 @@ pub fn list_replace_unsafe<'a, 'ctx, 'env>(
     let result = env
         .context
         .struct_type(
-            // TODO: does the order need to be decided by the size of the element type.
             &[
                 super::convert::zig_list_type(env).into(),
                 element_type.into(),
diff --git a/compiler/test_gen/src/gen_list.rs b/compiler/test_gen/src/gen_list.rs
index 18ce3051b5..2e3670c7fe 100644
--- a/compiler/test_gen/src/gen_list.rs
+++ b/compiler/test_gen/src/gen_list.rs
@@ -1736,6 +1736,57 @@ fn replace_unique_int_list_get_old_value() {
     );
 }
 
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn replace_unique_get_large_value() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+                list : List { a : U64, b: U64, c: U64, d: U64 }
+                list = [ { a: 1, b: 2, c: 3, d: 4 }, { a: 5, b: 6, c: 7, d: 8 }, { a: 9, b: 10, c: 11, d: 12 } ]
+                result = List.replace list 1 { a: 13, b: 14, c: 15, d: 16 }
+                when result is
+                    Ok {value} -> value
+                    Err _ -> { a: 0, b: 0, c: 0, d: 0 }
+            "#
+        ),
+        (5, 6, 7, 8),
+        (u64, u64, u64, u64)
+    );
+}
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn replace_shared_int_list() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+            wrapper = \shared ->
+                # This should not mutate the original
+                replaced =
+                    when List.replace shared 1 7.7 is
+                        Ok {list} -> list
+                        Err _ -> []
+                x =
+                    when List.get replaced 1 is
+                        Ok num -> num
+                        Err _ -> 0
+
+                y =
+                    when List.get shared 1 is
+                        Ok num -> num
+                        Err _ -> 0
+
+                { x, y }
+
+            wrapper [ 2.1, 4.3 ]
+            "#
+        ),
+        (7.7, 4.3),
+        (f64, f64)
+    );
+}
+
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
 fn get_set_unique_int_list() {