Repository: TypeScript
Issue: TypeScript 5.6 Iteration Plan
Labels: Planning

This document outlines our focused tasks for TypeScript 5.6. It minimally indicates intent to investigate tasks or contribute to an implementation. Nothing is set in stone, but we will strive to complete these tasks in a reasonable timeframe.

Date           | Event
---------------|-------------------------
2024-06-18     | TypeScript 5.5 Release
2024-07-19     | Create 5.6 Beta (5.6.0) Build for Testing
2024-07-23     | **TypeScript 5.6 Beta Release**
2024-08-16     | Create 5.6 RC (5.6.1) Build for Testing
2024-08-20     | **TypeScript 5.6 RC Release**
2024-08-30     | Create 5.6 Final (5.6.2) Build for Testing
2024-09-03     | **TypeScript 5.6 Final Release** 🚀


```mermaid
gantt
    dateFormat  YYYY-MM-DD
    TypeScript 5.5 Stabilization Period : 2024-06-10, 2024-06-18
    TypeScript 5.6 Beta Development : 2024-06-10, 2024-07-20
    TypeScript 5.6 RC Development : 2024-07-20, 2024-08-16
    TypeScript 5.6 Stabilization Period : 2024-08-16, 2024-09-03
todayMarker stroke-width:5px,stroke:#0f0,opacity:0.5
```


# Compiler and Language

* [Investigate Strict Callback Analysis](https://github.com/microsoft/TypeScript/pull/58729)
* [Stricter `TReturn` and `TNext` Types for `next()` on `Iterator`s](https://github.com/microsoft/TypeScript/pull/58243)
* [Checks for Never-Initialized Variables](https://github.com/microsoft/TypeScript/pull/55887)
* [ECMAScript Arbitrary Module Identifiers](https://github.com/microsoft/TypeScript/pull/58640)
* [Consult `type` in `node_modules/**/package.json` in More Module Modes](https://github.com/microsoft/TypeScript/pull/58825)
* [Spelling Suggestions for Named Capture Groups](https://github.com/microsoft/TypeScript/pull/58613)
* [Investigate `skipCheck`/`noCheck` in API and Batch-Mode Compilation](https://github.com/microsoft/TypeScript/pull/58626)
* [Build All Projects Under `--build` Irrespective of Errors](https://github.com/microsoft/TypeScript/pull/58854)
* [Investigate Non-Null Assertions in JSDoc](https://github.com/microsoft/TypeScript/pull/57042)
* [`lib.d.ts` Updates](https://github.com/microsoft/TypeScript/issues/58764)

# Editor and Language Service

* [Investigate Expandable Quick Info/Hover Verbosity](https://github.com/microsoft/TypeScript/issues/59029)
* [Region-Prioritized Error Checking](https://github.com/microsoft/TypeScript/issues/57393)
* [Investigate Simpler Quick Fix API](https://github.com/microsoft/TypeScript/issues/46249)
* [Investigate LSP Support](https://github.com/microsoft/TypeScript/issues/39459)
* [Auto-Import on Paste](https://github.com/microsoft/TypeScript/issues/50187)
* [Provide Deprecated Diagnostics on Namespaces Declared with `module` Keyword](https://github.com/microsoft/TypeScript/issues/57913)

# Performance

* [Investigate and Experiment with Full Monomorphization](https://github.com/microsoft/TypeScript/pull/58928)
* [Investigate Wildcard Matching Performance](https://github.com/microsoft/TypeScript/issues/59058)
* [Optimize Path Mapping Lookups](https://github.com/microsoft/TypeScript/pull/59048)
* [Investigate Deferring `TransformFlags` Calculation](https://github.com/microsoft/TypeScript/issues/58395)

# Website and Docs

* Revisit/Review Handbook and Experiences
* [Simplify and Refactor Website for Faster Builds](https://github.com/microsoft/TypeScript-Website/issues/2730)

# Infrastructure

* [Investigate Provenance or Build Signing](https://github.com/microsoft/TypeScript/issues/59028)
* [Experiment with Reduced Repros on Weekly New Error Runs](https://github.com/microsoft/typescript-error-deltas/issues/164)
* Adopt `--isolatedDeclarations` and Parallelize TypeScript's Build