fix: add variance annotations to fix file-order-dependent type errors

Add `in out` (invariant) variance annotations to `TData` and `TValue`
type parameters on all mutually recursive types in the ColumnDef/Column
cycle (ColumnDefBase, Column, Cell, Header, CoreColumn, CoreCell,
CoreHeader, HeaderContext, CellContext, GroupingColumnDef, and related
ColumnDef variants).

This works around a known TypeScript variance computation bug
(microsoft/TypeScript#44572) where file processing order causes tsc to
incorrectly cache TValue as [independent], silently making
ColumnDef<Row, string> assignable to ColumnDef<Row, unknown>.

Also makes TableFeature's createCell/createColumn/createHeader methods
generic over TValue (instead of hardcoding unknown) so that the
invariant TValue flows through correctly in implementation code.

Fixes #6167
Related: #4241, #4382

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Faithfinder

packages/table-core/src/core/cell.ts

@@ -1,7 +1,7 @@
 import { RowData, Cell, Column, Row, Table } from '../types'
 import { Getter, getMemoOptions, memo } from '../utils'
 
-export interface CellContext<TData extends RowData, TValue> {
+export interface CellContext<in out TData extends RowData, in out TValue> {
   cell: Cell<TData, TValue>
   column: Column<TData, TValue>
   getValue: Getter<TValue>
@@ -10,7 +10,7 @@ export interface CellContext<TData extends RowData, TValue> {
   table: Table<TData>
 }
 
-export interface CoreCell<TData extends RowData, TValue> {
+export interface CoreCell<in out TData extends RowData, in out TValue> {
   /**
    * The associated Column object for the cell.
    * @link [API Docs](https://tanstack.com/table/v8/docs/api/core/cell#column)

packages/table-core/src/core/column.ts

@@ -8,7 +8,7 @@ import {
 } from '../types'
 import { getMemoOptions, memo } from '../utils'
 
-export interface CoreColumn<TData extends RowData, TValue> {
+export interface CoreColumn<in out TData extends RowData, in out TValue> {
   /**
    * The resolved accessor function to use when extracting the value for the column from each row. Will only be defined if the column def has a valid accessor key or function defined.
    * @link [API Docs](https://tanstack.com/table/v8/docs/api/core/column#accessorfn)

packages/table-core/src/core/headers.ts

@@ -16,7 +16,7 @@ export interface CoreHeaderGroup<TData extends RowData> {
   id: string
 }
 
-export interface HeaderContext<TData, TValue> {
+export interface HeaderContext<in out TData, in out TValue> {
   /**
    * An instance of a column.
    */
@@ -31,7 +31,7 @@ export interface HeaderContext<TData, TValue> {
   table: Table<TData>
 }
 
-export interface CoreHeader<TData extends RowData, TValue> {
+export interface CoreHeader<in out TData extends RowData, in out TValue> {
   /**
    * The col-span for the header.
    * @link [API Docs](https://tanstack.com/table/v8/docs/api/core/header#colspan)

packages/table-core/src/features/ColumnFaceting.ts

@@ -46,8 +46,8 @@ export interface FacetedOptions<TData extends RowData> {
 //
 
 export const ColumnFaceting: TableFeature = {
-  createColumn: <TData extends RowData>(
-    column: Column<TData, unknown>,
+  createColumn: <TData extends RowData, TValue>(
+    column: Column<TData, TValue>,
     table: Table<TData>,
   ): void => {
     column._getFacetedRowModel =

packages/table-core/src/features/ColumnFiltering.ts

@@ -265,8 +265,8 @@ export const ColumnFiltering: TableFeature = {
     } as ColumnFiltersOptions<TData>
   },
 
-  createColumn: <TData extends RowData>(
-    column: Column<TData, unknown>,
+  createColumn: <TData extends RowData, TValue>(
+    column: Column<TData, TValue>,
     table: Table<TData>,
   ): void => {
     column.getAutoFilterFn = () => {
@@ -334,7 +334,7 @@ export const ColumnFiltering: TableFeature = {
 
         //
         if (
-          shouldAutoRemoveFilter(filterFn as FilterFn<TData>, newFilter, column)
+          shouldAutoRemoveFilter(filterFn as FilterFn<TData>, newFilter, column as Column<TData, unknown>)
         ) {
           return old?.filter((d) => d.id !== column.id) ?? []
         }

packages/table-core/src/features/ColumnGrouping.ts

@@ -34,7 +34,7 @@ export type AggregationFnOption<TData extends RowData> =
   | BuiltInAggregationFn
   | AggregationFn<TData>
 
-export interface GroupingColumnDef<TData extends RowData, TValue> {
+export interface GroupingColumnDef<in out TData extends RowData, in out TValue> {
   /**
    * The cell to display each row for the column if the cell is an aggregate. If a function is passed, it will be passed a props object with the context of the cell and should return the property type for your adapter (the exact type depends on the adapter being used).
    * @link [API Docs](https://tanstack.com/table/v8/docs/api/features/grouping#aggregatedcell)

packages/table-core/src/features/ColumnOrdering.ts

@@ -88,8 +88,8 @@ export const ColumnOrdering: TableFeature = {
     }
   },
 
-  createColumn: <TData extends RowData>(
-    column: Column<TData, unknown>,
+  createColumn: <TData extends RowData, TValue>(
+    column: Column<TData, TValue>,
     table: Table<TData>,
   ): void => {
     column.getIndex = memo(

packages/table-core/src/features/GlobalFiltering.ts

@@ -118,16 +118,16 @@ export const GlobalFiltering: TableFeature = {
     } as GlobalFilterOptions<TData>
   },
 
-  createColumn: <TData extends RowData>(
-    column: Column<TData, unknown>,
+  createColumn: <TData extends RowData, TValue>(
+    column: Column<TData, TValue>,
     table: Table<TData>,
   ): void => {
     column.getCanGlobalFilter = () => {
       return (
         (column.columnDef.enableGlobalFilter ?? true) &&
         (table.options.enableGlobalFilter ?? true) &&
         (table.options.enableFilters ?? true) &&
-        (table.options.getColumnCanGlobalFilter?.(column) ?? true) &&
+        (table.options.getColumnCanGlobalFilter?.(column as Column<TData, unknown>) ?? true) &&
         !!column.accessorFn
       )
     }

packages/table-core/src/types.ts

@@ -98,14 +98,20 @@ import { CellContext, CoreCell } from './core/cell'
 import { CoreColumn } from './core/column'
 
 export interface TableFeature<TData extends RowData = any> {
-  createCell?: (
-    cell: Cell<TData, unknown>,
-    column: Column<TData>,
+  createCell?: <TValue>(
+    cell: Cell<TData, TValue>,
+    column: Column<TData, TValue>,
     row: Row<TData>,
     table: Table<TData>,
   ) => void
-  createColumn?: (column: Column<TData, unknown>, table: Table<TData>) => void
-  createHeader?: (header: Header<TData, unknown>, table: Table<TData>) => void
+  createColumn?: <TValue>(
+    column: Column<TData, TValue>,
+    table: Table<TData>
+  ) => void
+  createHeader?: <TValue>(
+    header: Header<TData, TValue>,
+    table: Table<TData>
+  ) => void
   createRow?: (row: Row<TData>, table: Table<TData>) => void
   createTable?: (table: Table<TData>) => void
   getDefaultColumnDef?: () => Partial<ColumnDef<TData, unknown>>
@@ -227,7 +233,7 @@ export interface RowModel<TData extends RowData> {
   rowsById: Record<string, Row<TData>>
 }
 
-export type AccessorFn<TData extends RowData, TValue = unknown> = (
+export type AccessorFn<in TData extends RowData, out TValue = unknown> = (
   originalRow: TData,
   index: number,
 ) => TValue
@@ -256,7 +262,7 @@ type ColumnIdentifiers<TData extends RowData, TValue> =
 
 //
 
-interface ColumnDefExtensions<TData extends RowData, TValue = unknown>
+interface ColumnDefExtensions<in out TData extends RowData, in out TValue = unknown>
   extends
     VisibilityColumnDef,
     ColumnPinningColumnDef,
@@ -267,8 +273,8 @@ interface ColumnDefExtensions<TData extends RowData, TValue = unknown>
     ColumnSizingColumnDef {}
 
 export interface ColumnDefBase<
-  TData extends RowData,
-  TValue = unknown,
+  in out TData extends RowData,
+  in out TValue = unknown,
 > extends ColumnDefExtensions<TData, TValue> {
   getUniqueValues?: AccessorFn<TData, unknown[]>
   footer?: ColumnDefTemplate<HeaderContext<TData, TValue>>
@@ -279,8 +285,8 @@ export interface ColumnDefBase<
 //
 
 export interface IdentifiedColumnDef<
-  TData extends RowData,
-  TValue = unknown,
+  in out TData extends RowData,
+  in out TValue = unknown,
 > extends ColumnDefBase<TData, TValue> {
   id?: string
   header?: StringOrTemplateHeader<TData, TValue>
@@ -292,8 +298,8 @@ export type DisplayColumnDef<
 > = ColumnDefBase<TData, TValue> & ColumnIdentifiers<TData, TValue>
 
 interface GroupColumnDefBase<
-  TData extends RowData,
-  TValue = unknown,
+  in out TData extends RowData,
+  in out TValue = unknown,
 > extends ColumnDefBase<TData, TValue> {
   columns?: ColumnDef<TData, any>[]
 }
@@ -304,8 +310,8 @@ export type GroupColumnDef<
 > = GroupColumnDefBase<TData, TValue> & ColumnIdentifiers<TData, TValue>
 
 export interface AccessorFnColumnDefBase<
-  TData extends RowData,
-  TValue = unknown,
+  in out TData extends RowData,
+  in out TValue = unknown,
 > extends ColumnDefBase<TData, TValue> {
   accessorFn: AccessorFn<TData, TValue>
 }
@@ -316,8 +322,8 @@ export type AccessorFnColumnDef<
 > = AccessorFnColumnDefBase<TData, TValue> & ColumnIdentifiers<TData, TValue>
 
 export interface AccessorKeyColumnDefBase<
-  TData extends RowData,
-  TValue = unknown,
+  in out TData extends RowData,
+  in out TValue = unknown,
 > extends ColumnDefBase<TData, TValue> {
   id?: string
   accessorKey: (string & {}) | keyof TData
@@ -347,7 +353,7 @@ export type ColumnDefResolved<
   accessorKey?: string
 }
 
-export interface Column<TData extends RowData, TValue = unknown>
+export interface Column<in out TData extends RowData, in out TValue = unknown>
   extends
     CoreColumn<TData, TValue>,
     ColumnVisibilityColumn,
@@ -360,11 +366,13 @@ export interface Column<TData extends RowData, TValue = unknown>
     ColumnSizingColumn,
     ColumnOrderColumn {}
 
-export interface Cell<TData extends RowData, TValue>
-  extends CoreCell<TData, TValue>, GroupingCell {}
+export interface Cell<in out TData extends RowData, in out TValue>
+  extends CoreCell<TData, TValue>,
+    GroupingCell {}
 
-export interface Header<TData extends RowData, TValue>
-  extends CoreHeader<TData, TValue>, ColumnSizingHeader {}
+export interface Header<in out TData extends RowData, in out TValue>
+  extends CoreHeader<TData, TValue>,
+    ColumnSizingHeader {}
 
 export interface HeaderGroup<
   TData extends RowData,