diff --git a/compiler/load/tests/fixtures/build/app_with_deps/AStar.roc b/compiler/load/tests/fixtures/build/app_with_deps/AStar.roc
index 849c820a23..3c719d7642 100644
--- a/compiler/load/tests/fixtures/build/app_with_deps/AStar.roc
+++ b/compiler/load/tests/fixtures/build/app_with_deps/AStar.roc
@@ -25,7 +25,7 @@ initialModel = \start ->
 cheapestOpen : (position -> F64), Model position -> Result position [ KeyNotFound ]*
 cheapestOpen = \costFunction, model ->
 
-    folder = \position, resSmallestSoFar ->
+    folder = \resSmallestSoFar, position ->
             when Map.get model.costs position is
                 Err e ->
                     Err e
@@ -42,7 +42,7 @@ cheapestOpen = \costFunction, model ->
                             else
                                 Ok smallestSoFar
 
-    Set.walk model.openSet folder (Err KeyNotFound)
+    Set.walk model.openSet (Err KeyNotFound) folder
         |> Result.map (\x -> x.position)
 
 
@@ -105,7 +105,7 @@ astar = \costFn, moveFn, goal, model ->
 
                modelWithNeighbours = { modelPopped & openSet : Set.union modelPopped.openSet newNeighbours }
 
-               modelWithCosts = Set.walk newNeighbours (\nb, md -> updateCost current nb md) modelWithNeighbours
+               modelWithCosts = Set.walk newNeighbours modelWithNeighbours (\md, nb -> updateCost current nb md)
 
                astar costFn moveFn goal modelWithCosts
 
diff --git a/compiler/load/tests/fixtures/build/interface_with_deps/AStar.roc b/compiler/load/tests/fixtures/build/interface_with_deps/AStar.roc
index d2f35bd65a..2734330984 100644
--- a/compiler/load/tests/fixtures/build/interface_with_deps/AStar.roc
+++ b/compiler/load/tests/fixtures/build/interface_with_deps/AStar.roc
@@ -25,7 +25,7 @@ initialModel = \start ->
 cheapestOpen : (position -> F64), Model position -> Result position [ KeyNotFound ]*
 cheapestOpen = \costFunction, model ->
 
-    folder = \position, resSmallestSoFar ->
+    folder = \resSmallestSoFar, position ->
             when Dict.get model.costs position is
                 Err e ->
                     Err e
@@ -42,7 +42,7 @@ cheapestOpen = \costFunction, model ->
                             else
                                 Ok smallestSoFar
 
-    Set.walk model.openSet folder (Err KeyNotFound)
+    Set.walk model.openSet (Err KeyNotFound) folder
         |> Result.map (\x -> x.position)
 
 
@@ -105,7 +105,7 @@ astar = \costFn, moveFn, goal, model ->
 
                modelWithNeighbours = { modelPopped & openSet : Set.union modelPopped.openSet newNeighbours }
 
-               modelWithCosts = Set.walk newNeighbours (\nb, md -> updateCost current nb md) modelWithNeighbours
+               modelWithCosts = Set.walk newNeighbours modelWithNeighbours (\md, nb -> updateCost current nb md)
 
                astar costFn moveFn goal modelWithCosts
 
diff --git a/compiler/solve/tests/solve_expr.rs b/compiler/solve/tests/solve_expr.rs
index ecef19861b..fadd1d5a0b 100644
--- a/compiler/solve/tests/solve_expr.rs
+++ b/compiler/solve/tests/solve_expr.rs
@@ -3396,7 +3396,7 @@ mod solve_expr {
                 cheapestOpen : Model position -> Result position [ KeyNotFound ]*
                 cheapestOpen = \model ->
 
-                    folder = \position, resSmallestSoFar ->
+                    folder = \resSmallestSoFar, position ->
                                     when resSmallestSoFar is
                                         Err _ -> resSmallestSoFar
                                         Ok smallestSoFar ->
@@ -3689,7 +3689,7 @@ mod solve_expr {
                 List.walkBackwards
                 "#
             ),
-            "List a, b, (a, b -> b) -> b",
+            "List a, b, (b, a -> b) -> b",
         );
     }