From ccfdc9c9dfaec0d5e3998353f719e0a88dac5fa6 Mon Sep 17 00:00:00 2001
From: zyoshoka <107108195+zyoshoka@users.noreply.github.com>
Date: Sat, 22 Mar 2025 01:43:30 +0900
Subject: [PATCH 1/2] fix(eslint-plugin): [prefer-for-of] fix false positive
 when using non-null assertion within update expressions

---
 packages/eslint-plugin/src/util/isAssignee.ts     |  8 ++++++++
 .../tests/rules/prefer-for-of.test.ts             | 15 +++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/packages/eslint-plugin/src/util/isAssignee.ts b/packages/eslint-plugin/src/util/isAssignee.ts
index 9bf694827722..df3e53d4885d 100644
--- a/packages/eslint-plugin/src/util/isAssignee.ts
+++ b/packages/eslint-plugin/src/util/isAssignee.ts
@@ -53,5 +53,13 @@ export function isAssignee(node: TSESTree.Node): boolean {
     return true;
   }
 
+  // a[i]!++, [...a[i]!] = [0], etc.
+  if (
+    parent.type === AST_NODE_TYPES.TSNonNullExpression &&
+    isAssignee(parent)
+  ) {
+    return true;
+  }
+
   return false;
 }
diff --git a/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts b/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts
index 53a197f3f659..2d69ad0468dd 100644
--- a/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts
+++ b/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts
@@ -139,6 +139,16 @@ for (let i = 0; i < arr.length; i++) {
 }
     `,
     `
+for (let i = 0; i < arr.length; i++) {
+  arr[i]++;
+}
+    `,
+    `
+for (let i = 0; i < arr.length; i++) {
+  arr[i]!++;
+}
+    `,
+    `
 for (let i = 0; i < arr.length; i++) {
   [arr[i]] = [1];
 }
@@ -149,6 +159,11 @@ for (let i = 0; i < arr.length; i++) {
 }
     `,
     `
+for (let i = 0; i < arr.length; i++) {
+  [...arr[i]!] = [1];
+}
+    `,
+    `
 for (let i = 0; i < arr.length; i++) {
   ({ foo: arr[i] }) = { foo: 0 };
 }

From c2c9d6ae5d14e0695cb1a23ff1f989b5655ae861 Mon Sep 17 00:00:00 2001
From: zyoshoka <107108195+zyoshoka@users.noreply.github.com>
Date: Sun, 23 Mar 2025 12:57:00 +0900
Subject: [PATCH 2/2] fix(eslint-plugin): fix `isAssignee` function to handle
 any erasable type syntaxes

---
 packages/eslint-plugin/src/util/isAssignee.ts |  7 +++--
 .../tests/rules/prefer-for-of.test.ts         | 30 +++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/packages/eslint-plugin/src/util/isAssignee.ts b/packages/eslint-plugin/src/util/isAssignee.ts
index df3e53d4885d..4183468ab4d9 100644
--- a/packages/eslint-plugin/src/util/isAssignee.ts
+++ b/packages/eslint-plugin/src/util/isAssignee.ts
@@ -53,9 +53,12 @@ export function isAssignee(node: TSESTree.Node): boolean {
     return true;
   }
 
-  // a[i]!++, [...a[i]!] = [0], etc.
+  // (a[i] as number)++, [...a[i]!] = [0], etc.
   if (
-    parent.type === AST_NODE_TYPES.TSNonNullExpression &&
+    (parent.type === AST_NODE_TYPES.TSNonNullExpression ||
+      parent.type === AST_NODE_TYPES.TSAsExpression ||
+      parent.type === AST_NODE_TYPES.TSTypeAssertion ||
+      parent.type === AST_NODE_TYPES.TSSatisfiesExpression) &&
     isAssignee(parent)
   ) {
     return true;
diff --git a/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts b/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts
index 2d69ad0468dd..edc0e13519c8 100644
--- a/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts
+++ b/packages/eslint-plugin/tests/rules/prefer-for-of.test.ts
@@ -149,6 +149,36 @@ for (let i = 0; i < arr.length; i++) {
 }
     `,
     `
+for (let i = 0; i < arr.length; i++) {
+  arr[i]!!!++;
+}
+    `,
+    `
+for (let i = 0; i < arr.length; i++) {
+  (arr[i] as number)++;
+}
+    `,
+    `
+for (let i = 0; i < arr.length; i++) {
+  (<number>arr[i])++;
+}
+    `,
+    `
+for (let i = 0; i < arr.length; i++) {
+  (arr[i] as unknown as number)++;
+}
+    `,
+    `
+for (let i = 0; i < arr.length; i++) {
+  (arr[i] satisfies number)++;
+}
+    `,
+    `
+for (let i = 0; i < arr.length; i++) {
+  (arr[i]! satisfies number)++;
+}
+    `,
+    `
 for (let i = 0; i < arr.length; i++) {
   [arr[i]] = [1];
 }