fix: access to slots directly (#3671)

Co-authored-by: Johnson Chu <[email protected]>

Author: so1ve

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

@@ -99,6 +99,10 @@ export function generate(
 	let expectedErrorStart: undefined | number;
 	let expectedErrorNode: CompilerDOM.CommentNode | undefined;
 
+	if (slotsAssignName) {
+		localVars.set(slotsAssignName, 1);
+	}
+
 	if (propsAssignName) {
 		localVars.set(propsAssignName, 1);
 	}

packages/vue-test-workspace/vue-tsc/non-strict-template/#3671/main.vue

@@ -0,0 +1,7 @@
+<template>
+	{{ slots.footer }}
+</template>
+
+<script lang="ts" setup generic="T extends string">
+const slots = defineSlots<Record<T, () => any> & { footer(props: { id: number }): any}>();
+</script>