feat(types): infer emits from SetupContext in defineComponent

[zhiyuanzmj]

Remove the E extends any ? expression to correctly infer emits from SetupContext.

Don't worry, the #2362 issue has been resolved in this PR after 3.3.0-alpha-7.

Summary by CodeRabbit

• Refactor

  • Simplified component setup context type system for improved type inference.

• Tests

  • Added test coverage for component event typing in setup context.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR refactors the SetupContext type from a conditional type structure to a direct object type definition, eliminating the E extends any ? ... : never conditional logic while maintaining identical behavior. A test case is added to verify that SetupContext's emitted event typing is properly reflected in component props.

Changes

Cohort / File(s)	Summary
SetupContext Type Refactoring packages/runtime-core/src/component.ts	Simplified SetupContext type definition by removing the conditional E extends any distribution, converting it to a single straightforward object type with the same structural properties (attrs, slots, emit, expose).
SetupContext Type Inference Test packages-private/dts-test/defineComponent.test-d.tsx	Added test case verifying that SetupContext with typed emits (SetupContext<['foo']>) correctly infers component props, specifically validating that emitted events are reflected as listener props (e.g., onFoo).

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 hops with glee
The conditional chains have taken their flight,
SetupContext now gleams in pure, simple light!
No more E extends any to confuse the mind,
With tests to ensure all emissions align,
A cleaner type journey, how perfectly fine! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: refactoring SetupContext type to enable proper emit inference in defineComponent.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	105 kB	39.9 kB	35.8 kB
vue.global.prod.js	164 kB	59.9 kB	53.2 kB

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	48.3 kB	18.8 kB	17.2 kB
createApp	56.5 kB	21.8 kB	20 kB
createSSRApp	60.7 kB	23.6 kB	21.5 kB
defineCustomElement	62.6 kB	23.8 kB	21.7 kB
overall	71 kB	27.2 kB	24.7 kB

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commit: 0f93ce1

[Copilot]

Pull request overview

This PR adjusts Vue runtime-core TypeScript types to improve inferring component emits from an explicitly-typed SetupContext parameter in setup().

Changes:

• Simplifies SetupContext by removing the distributive conditional (E extends any ? ... : never).
• Adds a dts test ensuring JSX listeners (e.g. onFoo) are inferred when setup() annotates ctx as SetupContext<['foo']>.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/runtime-core/src/component.ts	Changes the exported SetupContext type definition (variance/inference behavior).
packages-private/dts-test/defineComponent.test-d.tsx	Adds a dts regression test for emits inference from SetupContext.

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[zhiyuanzmj]

/ecosystem-ci run

[vue-bot]

📝 Ran ecosystem CI: Open

suite	result	latest scheduled
nuxt	✅ success	❌ failure
radix-vue	✅ success	✅ success
test-utils	✅ success	✅ success
language-tools	❌ failure	❌ failure
pinia	✅ success	✅ success
primevue	✅ success	✅ success
vant	✅ success	✅ success
vueuse	✅ success	✅ success
vue-simple-compiler	✅ success	✅ success
vuetify	✅ success	❌ failure
vitepress	✅ success	✅ success
vue-i18n	✅ success	✅ success
quasar	✅ success	❌ failure
vite-plugin-vue	✅ success	✅ success
vue-macros	✅ success	✅ success
router	✅ success	❌ failure