diff --git a/compiler/builtins/src/std.rs b/compiler/builtins/src/std.rs
index b14d1dd435..273c1ee9a2 100644
--- a/compiler/builtins/src/std.rs
+++ b/compiler/builtins/src/std.rs
@@ -746,24 +746,24 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         Box::new(num_type(flex(TVAR1))),
     );
 
-    // walk : List elem, (elem -> accum -> accum), accum -> accum
+    // walk : List elem, state, (state, elem -> state) -> state
     add_top_level_function_type!(
         Symbol::LIST_WALK,
         vec![
             list_type(flex(TVAR1)),
-            closure(vec![flex(TVAR1), flex(TVAR2)], TVAR3, Box::new(flex(TVAR2))),
             flex(TVAR2),
+            closure(vec![flex(TVAR2), flex(TVAR1)], TVAR3, Box::new(flex(TVAR2))),
         ],
         Box::new(flex(TVAR2)),
     );
 
-    // walkBackwards : List elem, (elem -> accum -> accum), accum -> accum
+    // walkBackwards : List elem, state, (state, elem -> state) -> state
     add_top_level_function_type!(
         Symbol::LIST_WALK_BACKWARDS,
         vec![
             list_type(flex(TVAR1)),
-            closure(vec![flex(TVAR1), flex(TVAR2)], TVAR3, Box::new(flex(TVAR2))),
             flex(TVAR2),
+            closure(vec![flex(TVAR2), flex(TVAR1)], TVAR3, Box::new(flex(TVAR2))),
         ],
         Box::new(flex(TVAR2)),
     );
@@ -779,17 +779,17 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         )
     }
 
-    // walkUntil : List elem, (elem -> accum -> [ Continue accum, Stop accum ]), accum -> accum
+    // walkUntil : List elem, state, (state, elem -> [ Continue state, Stop state ]) -> state
     add_top_level_function_type!(
         Symbol::LIST_WALK_UNTIL,
         vec![
             list_type(flex(TVAR1)),
+            flex(TVAR2),
             closure(
                 vec![flex(TVAR1), flex(TVAR2)],
                 TVAR3,
                 Box::new(until_type(flex(TVAR2))),
             ),
-            flex(TVAR2),
         ],
         Box::new(flex(TVAR2)),
     );
diff --git a/compiler/can/src/builtins.rs b/compiler/can/src/builtins.rs
index 9c2f014586..fb3415691f 100644
--- a/compiler/can/src/builtins.rs
+++ b/compiler/can/src/builtins.rs
@@ -2050,8 +2050,8 @@ fn list_sum(symbol: Symbol, var_store: &mut VarStore) -> Def {
         op: LowLevel::ListWalk,
         args: vec![
             (list_var, Var(Symbol::ARG_1)),
-            (closure_var, list_sum_add(num_var, var_store)),
             (num_var, num(var_store.fresh(), 0)),
+            (closure_var, list_sum_add(num_var, var_store)),
         ],
         ret_var,
     };
@@ -2092,8 +2092,8 @@ fn list_product(symbol: Symbol, var_store: &mut VarStore) -> Def {
         op: LowLevel::ListWalk,
         args: vec![
             (list_var, Var(Symbol::ARG_1)),
-            (closure_var, list_product_mul(num_var, var_store)),
             (num_var, num(var_store.fresh(), 1)),
+            (closure_var, list_product_mul(num_var, var_store)),
         ],
         ret_var,
     };