ArgsTable: Add warning when subcomponents is an array

addons/docs/src/blocks/ArgsTable.tsx

@@ -193,6 +193,11 @@ export const StoryTable: FC<
     }
 
     if (subcomponents) {
+      if (Array.isArray(subcomponents)) {
+        throw new Error(
+          `Unexpected subcomponents array. Expected an object whose keys are tab labels and whose values are components.`
+        );
+      }
       tabs = addComponentTabs(tabs, subcomponents, context, include, exclude);
     }
     return <TabbedArgsTable tabs={tabs} />;

examples/official-storybook/stories/addon-docs/array-subcomponents.stories.js

@@ -0,0 +1,10 @@
+import React from 'react';
+import Button from '../../components/TsButton';
+
+export default {
+  title: 'Addons/Docs/Subcomponents array',
+  component: Button,
+  subcomponents: [Button],
+};
+
+export const Basic = () => <Button>Bad subcomponents</Button>;