fix: don't show a type error on nil for lists

closes #1166

lib/ash/query/operator/operator.ex

@@ -168,7 +168,11 @@ defmodule Ash.Query.Operator do
     end)
     |> case do
       nil ->
-        {:error, "Could not cast expression: #{inspect(mod)} #{inspect(left)} #{inspect(right)}"}
+        {:error,
+         Ash.Error.Query.InvalidFilterValue.exception(
+           value: struct(mod, left: left, right: right),
+           message: "No matching types. Possible types: #{inspect(mod.types())}"
+         )}
 
       {:error, error} ->
         {:error, error}

lib/ash/query/type.ex

@@ -17,7 +17,11 @@ defmodule Ash.Query.Type do
         {:ok, val} -> {:ok, Enum.reverse(val)}
       end
     else
-      :error
+      if is_nil(list) do
+        {:ok, list}
+      else
+        :error
+      end
     end
   end
 

test/filter/filter_test.exs

@@ -71,6 +71,18 @@ defmodule Ash.Test.Filter.FilterTest do
     actions do
       default_accept :*
       defaults [:read, :destroy, create: :*, update: :*]
+
+      read :with_invalid_value_behind_is_nil_check do
+        argument :ids, {:array, :uuid}
+
+        filter expr(
+                 if not is_nil(^arg(:ids)) do
+                   id in ^arg(:ids)
+                 else
+                   true
+                 end
+               )
+      end
     end
 
     attributes do
@@ -861,6 +873,13 @@ defmodule Ash.Test.Filter.FilterTest do
     end
   end
 
+  test "errors are not produced by eager evaluation" do
+    assert [] =
+             User
+             |> Ash.Query.for_read(:with_invalid_value_behind_is_nil_check, %{})
+             |> Ash.read!()
+  end
+
   describe "calls in filters" do
     test "calls are evaluated and can be used in predicates" do
       post1 =