Keep the Cell of a column checked, and let any column be read

table/src/-private/-type-tests/cell-args.test.ts

@@ -15,6 +15,7 @@ import { meta } from '../../plugins/index.ts';
 
 import type { CellContext, Column, ColumnConfig, Table } from '../../index.ts';
 import type { ComponentLike } from '@glint/template';
+import type { CellComponent } from '../cell-component.ts';
 
 interface Person {
   name: string;
@@ -37,7 +38,11 @@ declare const UpdateCell: ComponentLike<
 declare const PlainCell: ComponentLike<CellContext<Person>>;
 
 type CellArgsOf<Cell> =
-  NonNullable<Cell> extends ComponentLike<infer Args> ? Args : never;
+  NonNullable<Cell> extends CellComponent<infer Args>
+    ? Args
+    : NonNullable<Cell> extends ComponentLike<infer Args>
+      ? Args
+      : never;
 
 /////////////////////////////////////////////
 // The args of the Cells are inferred, besides `@row` and `@column`

table/src/-private/cell-component.ts

@@ -0,0 +1,32 @@
+import type {
+  ComponentReturn,
+  FlattenBlockParams,
+  Invoke,
+} from '@glint/template/-private/integration';
+import type {
+  ComponentSignatureArgs,
+  ComponentSignatureBlocks,
+  ComponentSignatureElement,
+  InvokableArgs,
+} from '@glint/template/-private/signature';
+
+/**
+ * A component rendered as a cell, invoked the way `ComponentLike` is.
+ *
+ * `[Invoke]` is a method here, where `ComponentLike` declares it as a property.
+ * TypeScript compares the parameters of a method bivariantly, so a column whose
+ * Cell asks for args fits a `Column<DataType>` that names none, while the args
+ * are still checked where the Cell is rendered.
+ *
+ * With a property, those two cannot both hold: the args of a property function
+ * are contravariant, so the only way to make such a column fit is `any`, which
+ * stops the Cell being checked at all.
+ */
+export type CellComponent<S = unknown> = abstract new (...args: any) => {
+  [Invoke](
+    ...args: InvokableArgs<ComponentSignatureArgs<S>>
+  ): ComponentReturn<
+    FlattenBlockParams<ComponentSignatureBlocks<S>>,
+    ComponentSignatureElement<S>
+  >;
+};

table/src/-private/column.ts

@@ -1,6 +1,7 @@
 import { action, get } from '@ember/object';
 import { isEmpty } from '@ember/utils';
 
+import type { CellComponent } from './cell-component.ts';
 import type { Row } from './row';
 import type { Table } from './table';
 import type { ComponentLike, ContentValue } from '@glint/template';
@@ -24,13 +25,13 @@ export class Column<
   T = unknown,
   ColumnMeta = unknown,
   Meta = unknown,
-  CellArgs = any,
+  CellArgs = unknown,
 > {
   get Cell():
-    | ComponentLike<CellContext<T, unknown, any> & CellArgs>
+    | CellComponent<CellContext<T, unknown, any> & CellArgs>
     | undefined {
     return this.config.Cell as
-      | ComponentLike<CellContext<T, unknown, any> & CellArgs>
+      | CellComponent<CellContext<T, unknown, any> & CellArgs>
       | undefined;
   }
 

table/src/-private/table.ts

@@ -55,7 +55,7 @@ export interface Table<
   DataType = unknown,
   ColumnMeta = unknown,
   Meta = unknown,
-  CellArgs = any,
+  CellArgs = unknown,
 > {
   /**
    * @private
@@ -87,7 +87,7 @@ export class Table<
   DataType = unknown,
   ColumnMeta = unknown,
   Meta = unknown,
-  CellArgs = any,
+  CellArgs = unknown,
 > {
   /**
    * @private

test-app/tests/integration/cells-test.gts

@@ -6,7 +6,7 @@ import { setupRenderingTest } from "ember-qunit";
 import { headlessTable } from "@universal-ember/table";
 
 import type { TOC } from "@ember/component/template-only";
-import type { CellContext } from "@universal-ember/table";
+import type { CellContext, Column } from "@universal-ember/table";
 
 interface Person {
   name: string;
@@ -133,3 +133,23 @@ const TypeChecks: TOC<{ Args: { table: Context["table"] } }> = <template>
 </template>;
 
 void TypeChecks;
+
+/**
+ * A column written by hand, rather than one a table inferred.
+ *
+ * Its Cell takes `@row` and `@column` and nothing else, so leaving them out is
+ * an error. On 4.0.0 `Cell` was `ComponentLike<CellContext<T>>` and this held.
+ */
+declare const handWritten: Column<Person>;
+
+const HandWrittenColumnChecks: TOC<object> = <template>
+  {{#if handWritten.Cell}}
+    {{! @glint-expect-error a Cell is given @row and @column }}
+    <handWritten.Cell />
+
+    {{! @glint-expect-error a Cell is not given args it does not take }}
+    <handWritten.Cell @row={{undefined}} @column={{handWritten}} @nope="x" />
+  {{/if}}
+</template>;
+
+void HandWrittenColumnChecks;