diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f76bd24..dc50908 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,11 +29,16 @@ jobs:
       matrix:
         os: [ubuntu-latest, windows-latest]
         crystal_version: [latest]
+        experimental: [false]
         include:
           - os: ubuntu-latest
             crystal_version: 1.4.0
+            experimental: false
+          - os: ubuntu-latest
+            crystal_version: nightly
+            experimental: true
     runs-on: ${{ matrix.os }}
-    continue-on-error: false
+    continue-on-error: ${{ matrix.experimental }}
     steps:
       - uses: actions/checkout@v3
       - uses: crystal-lang/install-crystal@v1
diff --git a/src/habitat.cr b/src/habitat.cr
index d6a8e8a..a80fcda 100644
--- a/src/habitat.cr
+++ b/src/habitat.cr
@@ -34,7 +34,7 @@ class Habitat
       {% for type in TYPES_WITH_HABITAT %}
         {% for setting in type.constant(:HABITAT_SETTINGS) %}
         {% if !setting[:decl].type.is_a?(Union) ||
-                (setting[:decl].type.is_a?(Union) && !setting[:decl].type.types.map(&.id).includes?(Nil.id)) %}
+                (setting[:decl].type.is_a?(Union) && !setting[:decl].type.types.any?(&.names.includes?(Nil.id))) %}
             if {{ type }}.settings.{{ setting[:decl].var }}?.nil?
               raise MissingSettingError.new {{ type }}, setting_name: {{ setting[:decl].var.stringify }}, example: {{ setting[:example] }}
             end
@@ -231,7 +231,7 @@ class Habitat
         # NOTE: We can't use the macro level `type.resolve.nilable?` here because
         # there's a few declaration types that don't respond to it which would make the logic
         # more complex. Metaclass, and Proc types are the main, but there may be more.
-        {% if decl.type.is_a?(Union) && decl.type.types.map(&.id).includes?(Nil.id) %}
+        {% if decl.type.is_a?(Union) && decl.type.types.any?(&.names.includes?(Nil.id)) %}
           {% nilable = true %}
         {% else %}
           {% nilable = false %}