From 62992b2fb7d1ba3a2f36cee372748760c187323c Mon Sep 17 00:00:00 2001
From: mdm317 <dbswh1008@gmail.com>
Date: Thu, 2 Jan 2025 23:04:38 +0900
Subject: [PATCH] fix : work with enum

---
 .../rules/no-unnecessary-type-assertion.ts    |  3 ++-
 .../no-unnecessary-type-assertion.test.ts     | 27 +++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/packages/eslint-plugin/src/rules/no-unnecessary-type-assertion.ts b/packages/eslint-plugin/src/rules/no-unnecessary-type-assertion.ts
index c73d8717c3e1..d11a40f85825 100644
--- a/packages/eslint-plugin/src/rules/no-unnecessary-type-assertion.ts
+++ b/packages/eslint-plugin/src/rules/no-unnecessary-type-assertion.ts
@@ -226,7 +226,8 @@ export default createRule<Options, MessageIds>({
 
         const wouldSameTypeBeInferred = castType.isLiteral()
           ? isImplicitlyNarrowedConstDeclaration(node)
-          : !isConstAssertion(node.typeAnnotation);
+          : checker.isTypeAssignableTo(castType, uncastType) &&
+            !isConstAssertion(node.typeAnnotation);
 
         if (typeIsUnchanged && wouldSameTypeBeInferred) {
           context.report({
diff --git a/packages/eslint-plugin/tests/rules/no-unnecessary-type-assertion.test.ts b/packages/eslint-plugin/tests/rules/no-unnecessary-type-assertion.test.ts
index db8309164efb..8853d0c111dd 100644
--- a/packages/eslint-plugin/tests/rules/no-unnecessary-type-assertion.test.ts
+++ b/packages/eslint-plugin/tests/rules/no-unnecessary-type-assertion.test.ts
@@ -1151,5 +1151,32 @@ const a = '';
 const b: string | undefined = (a ? undefined : a);
       `,
     },
+    {
+      code: `
+enum MyEnum {
+  Value1,
+}
+
+declare const myEnum: MyEnum.Value1;
+
+const myEnumCast = myEnum as MyEnum.Value1;
+      `,
+      errors: [
+        {
+          column: 20,
+          line: 8,
+          messageId: 'unnecessaryAssertion',
+        },
+      ],
+      output: `
+enum MyEnum {
+  Value1,
+}
+
+declare const myEnum: MyEnum.Value1;
+
+const myEnumCast = myEnum;
+      `,
+    },
   ],
 });