Merge pull request #19139 from twbs/v4-custom-forms-validation

v4: Validation states on custom forms

docs/components/forms.md

@@ -764,6 +764,33 @@ Custom checkboxes and radios can also be disabled. Add the `disabled` boolean at
 </label>
 {% endexample %}
 
+#### Validation states
+
+Add other states to your custom forms with our validation classes.
+
+{% example html %}
+<div class="form-group has-success">
+  <label class="custom-control custom-checkbox">
+    <input type="checkbox" class="custom-control-input">
+    <span class="custom-control-indicator"></span>
+    <span class="custom-control-description">Check this custom checkbox</span>
+  </label>
+</div>
+<div class="form-group has-warning">
+  <label class="custom-control custom-checkbox">
+    <input type="checkbox" class="custom-control-input">
+    <span class="custom-control-indicator"></span>
+    <span class="custom-control-description">Check this custom checkbox</span>
+  </label>
+</div>
+<div class="form-group has-danger m-b-0">
+  <label class="custom-control custom-checkbox">
+    <input type="checkbox" class="custom-control-input">
+    <span class="custom-control-indicator"></span>
+    <span class="custom-control-description">Check this custom checkbox</span>
+  </label>
+</div>
+{% endexample %}
 
 #### Stacked
 

scss/mixins/_forms.scss

@@ -14,7 +14,8 @@
   &.radio label,
   &.checkbox label,
   &.radio-inline label,
-  &.checkbox-inline label  {
+  &.checkbox-inline label,
+  .custom-control {
     color: $color;
   }
   // Set the border and box shadow on specific inputs to match