https://devblogs.microsoft.com/typescript/announcing-typescript-5-3-beta/

This issue is just to track all of the new features and their implementation state in this project.
As with all releases, we will not necessarily to support all features until closer to the full release when everything the features are stabilised.

Please be patient.

✅ Import Attributes (#7821)

We should take this opportunity to deprecate ourimport/export.assertions property, and instead implement theimport/export.attributes property. The AST shape is otherwise unchanged so it should just be a property deprecation.

From the TS AST side - they deprecated the.assertClause property that we currently use to get the attributes and the intended replacement is.attributes. Otherwise no changes.

✅ Optimizations by Skipping JSDoc Parsing (#7821)

Our usecase was one of the motivators for this change!
We'll want to ensure we are parsing withhost.jsDocParsingMode = JSDocParsingMode.ParseForTypeInfo.

This should reduce memory usage and improve parsing performance.

✅ lib.d.ts Updates (#7923)

We will need to regenerate our types withinscope-manager.

Other changes with no impact to us

• Stable Supportresolution-mode in Import Types
• switch (true) Narrowing
  • it's not treated the same as anif condition - so we don't need to worry about updating our rules to match this, I think?
• Narrowing On Comparisons to Booleans
• instanceof Narrowing ThroughSymbol.hasInstance
• Checks forsuper Property Accesses on Instance Fields
• Interactive Inlay Hints for Types
• Optimizations by Comparing Non-Normalized Intersections
• Consolidation Between tsserverlibrary.js and typescript.js
  • Once we drop <5.3 we can switch everything to import from the root export. But for now we need backwards compat.
• Breaking Changes and Correctness Improvements
  lib.d.ts Changes
  • Checks forsuper Accesses on Instance Properties