fix(types): infer discriminated unions in child component props (#3672)

Author: davidmatter

packages/vue-language-core/src/generators/script.ts

@@ -377,7 +377,7 @@ export function generate(
 			//#endregion
 
 			codes.push('return {} as {\n');
-			codes.push(`props: __VLS_Prettify<Omit<typeof __VLS_fnPropsDefineComponent & typeof __VLS_fnPropsTypeOnly, keyof typeof __VLS_defaultProps>> & typeof __VLS_fnPropsSlots & typeof __VLS_defaultProps,\n`);
+			codes.push(`props: __VLS_Prettify<__VLS_OmitKeepDiscriminatedUnion<typeof __VLS_fnPropsDefineComponent & typeof __VLS_fnPropsTypeOnly, keyof typeof __VLS_defaultProps>> & typeof __VLS_fnPropsSlots & typeof __VLS_defaultProps,\n`);
 			codes.push(`expose(exposed: import('${vueCompilerOptions.lib}').ShallowUnwrapRef<${scriptSetupRanges.expose.define ? 'typeof __VLS_exposed' : '{}'}>): void,\n`);
 			codes.push('attrs: any,\n');
 			codes.push('slots: ReturnType<typeof __VLS_template>,\n');

packages/vue-language-core/src/utils/globalTypes.ts

@@ -15,6 +15,11 @@ type __VLS_PickNotAny<A, B> = __VLS_IsAny<A> extends true ? B : A;
 
 type __VLS_Prettify<T> = { [K in keyof T]: T[K]; } & {};
 
+type __VLS_OmitKeepDiscriminatedUnion<T, K extends keyof any> =
+	T extends any
+		? Pick<T, Exclude<keyof T, K>>
+		: never;
+
 type __VLS_GlobalComponents =
 	__VLS_PickNotAny<import('vue').GlobalComponents, {}>
 	& __VLS_PickNotAny<import('@vue/runtime-core').GlobalComponents, {}>

packages/vue-test-workspace/vue-tsc/non-strict-template/#3672/child.vue

@@ -0,0 +1,15 @@
+<script setup lang="ts" generic="T extends string | number">
+interface InputProps {
+	type?: 'input';
+	value: (k: T) => void;
+	typeDefinition: T;
+}
+
+interface SelectProps {
+	type: 'select';
+	value: (k: T[]) => void;
+	typeDefinition: T;
+}
+
+defineProps<InputProps | SelectProps>()
+</script>

packages/vue-test-workspace/vue-tsc/non-strict-template/#3672/main.vue

@@ -0,0 +1,13 @@
+<script setup lang="ts">
+import child from './child.vue';
+import { exactType } from '../../shared';
+import { ref } from 'vue';
+
+const input = ref(3);
+const select = ref('asdf');
+</script>
+
+<template>
+	<child type="select" :typeDefinition="select" :value="k => exactType(k, {} as string[])"></child>
+	<child type="input" :typeDefinition="input" :value="k => exactType(k, {} as number)"></child>
+</template>