[Copilot]

Nested object bindings with = {} incorrectly reported TS7031 despite an enclosing parameter annotation supplying the binding element type.

function f({ inner: { b } = {} }: Outer) {
    return b; // number | undefined, not any
}

• Cause

  • Object-literal padding reported implicit-any for every missing binding element, including elements rooted in annotated declarations.

• Change

  • Report implicit-any during padding only when the root declaration lacks a type annotation.
  • Add regression coverage for nested bindings with and without sibling defaults.

• Fixes TS7031 false positive for nested object binding pattern with = {} default in an annotated parameter (regression from #64043) #64431

[Ryan Cavanaugh (RyanCavanaugh)]

Copilot mcfly this and also explain why this is a correct fix

[Trevor Florence (trevorade)]

I had my agent check this fix. Here's what it has to say about it.

---

Tried this against the cases we hit in our codebase. It clears all of them, and it also gets the types right in a nested callback case (deepCb(({inner: {b} = {}}) => b) gives b: string | undefined, same as 6.0).

Two cases still differ from 6.0.3:

// 1. Contextual type is `any`: TS7031 on `a` (6.0.3: clean)
declare function anyCb(cb: (x: any) => void): void;
anyCb(({a} = {}) => { void a; });

// 2. One element missing from the contextual type: TS7031 on `q` too (6.0.3: only TS2339 on `extra`)
interface Opts { q?: string; }
declare function onTab(cb: (id: string, opts?: Opts) => void): void;
onTab((id, {q, extra} = {}) => { void [id, q, extra]; });

(2) happens because hasContextualTypeForObjectBindingPattern is all-or-nothing, so one element without a contextual property type re-pads the whole pattern.

Also, the .types/.symbols baselines are missing the contextual(...) line from the test file, so TestLocal/objectBindingPatternDefaultAnnotated.ts fails as-is. No other baselines change.