@@ -966,6 +966,47 @@ describe('emits', () => {
 }
 }
 })
+
+// should have `onXXX` props for emits
+const a = defineComponent({
+props: {
+bar: String
+},
+emits: {
+foo: (n: number) => n > 0
+},
+setup(props) {
+expectType<((n: number) => boolean) | undefined>(props.onFoo)
+}
+})
+
+const b = defineComponent({
+extends: a,
+props: {
+bar2: String
+},
+emits: {
+foo2: (n: number) => n > 0
+},
+setup(props) {
+expectType<((n: number) => boolean) | undefined>(props.onFoo)
+}
+})
+
+defineComponent({
+mixins: [a, b],
+props: {
+bar3: String
+},
+emits: {
+foo3: (n: number) => n > 0
+},
+setup(props) {
+expectType<((n: number) => boolean) | undefined>(props.onFoo)
+expectType<((n: number) => boolean) | undefined>(props.onFoo2)
+expectType<((n: number) => boolean) | undefined>(props.onFoo3)
+}
+})
 })
 
 // describe('componentOptions setup should be `SetupContext`', () => {

@@ -1,7 +1,7 @@
 import { Vue } from './vue'
 import { VNode } from './vnode'
 import { ComponentOptions as Vue2ComponentOptions } from './options'
-import { EmitsOptions, SetupContext } from './v3-setup-context'
+import { EmitsOptions, EmitsToProps, SetupContext } from './v3-setup-context'
 import { Data, LooseRequired, UnionToIntersection } from './common'
 import {
 ComponentPropsOptions,
@@ -52,7 +52,7 @@ export type SetupFunction<
 Emits extends EmitsOptions = {}
 > = (
 this: void,
-props: Readonly<Props>,
+props: Readonly<Props & EmitsToProps<Emits>>,
 ctx: SetupContext<Emits>
 ) => RawBindings | (() => VNode | null) | void
 

@@ -17,7 +17,7 @@ import {
 CreateComponentPublicInstance
 } from './v3-component-public-instance'
 import { Data, HasDefined } from './common'
-import { EmitsOptions } from './v3-setup-context'
+import { EmitsOptions, EmitsToProps } from './v3-setup-context'
 import { CreateElement, RenderContext } from './umd'
 
 export type DefineComponent<
@@ -31,9 +31,9 @@ export type DefineComponent<
 E extends EmitsOptions = {},
 EE extends string = string,
 Props = Readonly<
-PropsOrPropOptions extends ComponentPropsOptions
+(PropsOrPropOptions extends ComponentPropsOptions
 ? ExtractPropTypes<PropsOrPropOptions>
-: PropsOrPropOptions
+: PropsOrPropOptions) & EmitsToProps<E>
 >,
 Defaults = ExtractDefaultPropTypes<PropsOrPropOptions>
 > = ComponentPublicInstanceConstructor<

@@ -13,6 +13,25 @@ export type ObjectEmitsOptions = Record<
 
 export type EmitsOptions = ObjectEmitsOptions | string[]
 
+export type EmitsToProps<T extends EmitsOptions> = T extends string[]
+? {
+[K in string & `on${Capitalize<T[number]>}`]?: (...args: any[]) => any
+}
+: T extends ObjectEmitsOptions
+? {
+[K in string &
+`on${Capitalize<string & keyof T>}`]?: K extends `on${infer C}`
+? T[Uncapitalize<C>] extends null
+? (...args: any[]) => any
+: (
+...args: T[Uncapitalize<C>] extends (...args: infer P) => any
+? P
+: never
+) => any
+: never
+}
+: {}
+
 export type EmitFn<
 Options = ObjectEmitsOptions,
 Event extends keyof Options = keyof Options,