feat(runtime-core): type and attr fallthrough support for emits option

test-dts/functionalComponent.test-d.tsx

@@ -0,0 +1,39 @@
+import { expectError, expectType } from 'tsd'
+import { FunctionalComponent } from './index'
+
+// simple function signature
+const Foo = (props: { foo: number }) => props.foo
+
+// TSX
+expectType<JSX.Element>(<Foo foo={1} />)
+expectError(<Foo />)
+expectError(<Foo foo="bar" />)
+
+// Explicit signature with props + emits
+const Bar: FunctionalComponent<
+  { foo: number },
+  { update: (value: number) => void }
+> = (props, { emit }) => {
+  expectType<number>(props.foo)
+
+  emit('update', 123)
+  expectError(emit('nope'))
+  expectError(emit('update'))
+  expectError(emit('update', 'nope'))
+}
+
+// assigning runtime options
+Bar.props = {
+  foo: Number
+}
+expectError((Bar.props = { foo: String }))
+
+Bar.emits = {
+  update: value => value > 1
+}
+expectError((Bar.emits = { baz: () => void 0 }))
+
+// TSX
+expectType<JSX.Element>(<Bar foo={1} />)
+expectError(<Bar />)
+expectError(<Bar foo="bar" />)