fix(language-core): generate condition guards for model events (#5225)

Author: KazariEX

packages/language-core/lib/codegen/template/context.ts

@@ -242,6 +242,11 @@ export function createTemplateCodegenContext(options: Pick<TemplateCodegenOption
 				yield endOfLine;
 			}
 		},
+		generateConditionGuards: function* () {
+			for (const condition of blockConditions) {
+				yield `if (!${condition}) return${endOfLine}`;
+			}
+		},
 		ignoreError: function* (): Generator<Code> {
 			if (!ignoredError) {
 				ignoredError = true;

packages/language-core/lib/codegen/template/elementEvents.ts

@@ -122,12 +122,9 @@ export function* generateEventExpression(
 		if (_isCompoundExpression) {
 			yield `(...[$event]) => {${newLine}`;
 			ctx.addLocalVariable('$event');
-
+			yield* ctx.generateConditionGuards();
 			prefix = ``;
 			suffix = ``;
-			for (const blockCondition of ctx.blockConditions) {
-				prefix += `if (!${blockCondition}) return${endOfLine}`;
-			}
 		}
 
 		yield* generateInterpolation(
@@ -178,7 +175,8 @@ export function* generateModelEventExpression(
 	prop: CompilerDOM.DirectiveNode
 ): Generator<Code> {
 	if (prop.exp?.type === CompilerDOM.NodeTypes.SIMPLE_EXPRESSION) {
-		yield `(...[$event]) => (`;
+		yield `(...[$event]) => {${newLine}`;
+		yield* ctx.generateConditionGuards();
 		yield* generateInterpolation(
 			options,
 			ctx,
@@ -188,7 +186,8 @@ export function* generateModelEventExpression(
 			prop.exp.loc.start.offset,
 			prop.exp.loc
 		);
-		yield ` = $event)`;
+		yield ` = $event${endOfLine}`;
+		yield `}`;
 	}
 	else {
 		yield `() => {}`;

test-workspace/tsc/passedFixtures/vue2/tsconfig.json

@@ -29,6 +29,7 @@
 		"../vue3/#4822",
 		"../vue3/#4826",
 		"../vue3/#4828",
+		"../vue3/#5225",
 		"../vue3/attrs",
 		"../vue3/components",
 		"../vue3/defineEmits",

test-workspace/tsc/passedFixtures/vue3/#5225/comp.vue

@@ -0,0 +1,3 @@
+<script setup lang="ts">
+defineModel<number>({ required: true });
+</script>

test-workspace/tsc/passedFixtures/vue3/#5225/main.vue

@@ -0,0 +1,13 @@
+<script setup lang="ts">
+import Comp from './comp.vue';
+
+let foo!: {
+    bar?: number;
+};
+</script>
+
+<template>
+    <!-- @vue-expect-error -->
+    <Comp v-model="foo.bar" />
+    <Comp v-if="foo.bar" v-model="foo.bar" />
+</template>