From 40760f98da0d23c7bce3da04cf37a56c10447bde Mon Sep 17 00:00:00 2001
From: Flo Edelmann <florian-edelmann@online.de>
Date: Sun, 3 Oct 2021 23:53:52 +0200
Subject: [PATCH] fix(eslint-plugin): [non-nullable-type-assertion-style]
 false-positive with non-nullish `as` assertions and types (#3940)

---
 .../src/rules/non-nullable-type-assertion-style.ts         | 4 ++++
 .../tests/rules/non-nullable-type-assertion-style.test.ts  | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/packages/eslint-plugin/src/rules/non-nullable-type-assertion-style.ts b/packages/eslint-plugin/src/rules/non-nullable-type-assertion-style.ts
index eef8c58445f..647fbcddd4c 100644
--- a/packages/eslint-plugin/src/rules/non-nullable-type-assertion-style.ts
+++ b/packages/eslint-plugin/src/rules/non-nullable-type-assertion-style.ts
@@ -57,6 +57,10 @@ export default util.createRule({
           type.flags !== ts.TypeFlags.Undefined,
       );
 
+      if (nonNullishOriginalTypes.length === originalTypes.length) {
+        return false;
+      }
+
       for (const assertedType of assertedTypes) {
         if (!nonNullishOriginalTypes.includes(assertedType)) {
           return false;
diff --git a/packages/eslint-plugin/tests/rules/non-nullable-type-assertion-style.test.ts b/packages/eslint-plugin/tests/rules/non-nullable-type-assertion-style.test.ts
index 33c603135f5..fadd5064abd 100644
--- a/packages/eslint-plugin/tests/rules/non-nullable-type-assertion-style.test.ts
+++ b/packages/eslint-plugin/tests/rules/non-nullable-type-assertion-style.test.ts
@@ -54,6 +54,13 @@ const y = x as NonNullable<T>;
     `
 const foo = [] as const;
     `,
+    `
+const x = 1 as 1;
+    `,
+    `
+declare function foo<T = any>(): T;
+const bar = foo() as number;
+    `,
   ],
 
   invalid: [