From 479a54de663bb29b32cfe22ef52576b2672e263a Mon Sep 17 00:00:00 2001
From: fisker Cheung <lionkay@gmail.com>
Date: Fri, 12 Sep 2025 01:53:02 +0800
Subject: [PATCH] Add missing parentheses to arrow function in
 `TSInstantiationExpression` (#17724)

---
 changelog_unreleased/typescript/17724.md           | 13 +++++++++++++
 src/language-js/needs-parens.js                    |  3 +++
 .../typescript/instantiation-expression/17714.ts   |  1 +
 .../__snapshots__/format.test.js.snap              | 14 ++++++++++++++
 4 files changed, 31 insertions(+)
 create mode 100644 changelog_unreleased/typescript/17724.md
 create mode 100644 tests/format/typescript/instantiation-expression/17714.ts

diff --git a/changelog_unreleased/typescript/17724.md b/changelog_unreleased/typescript/17724.md
new file mode 100644
index 000000000..6e4951d0b
--- /dev/null
+++ b/changelog_unreleased/typescript/17724.md
@@ -0,0 +1,13 @@
+#### Add missing parentheses to arrow function in instantiation expression (#17724 by @fisker)
+
+<!-- prettier-ignore -->
+```tsx
+// Input
+void (<_T extends never>() => {})<never>;
+
+// Prettier stable
+void <_T extends never>() => {}<never>;
+
+// Prettier main
+void (<_T extends never>() => {})<never>;
+```
diff --git a/src/language-js/needs-parens.js b/src/language-js/needs-parens.js
index b6aca54a2..9779ae14d 100644
--- a/src/language-js/needs-parens.js
+++ b/src/language-js/needs-parens.js
@@ -881,6 +881,9 @@ function needsParens(path, options) {
         case "MatchExpressionCase":
           return true;
 
+        case "TSInstantiationExpression":
+          return key === "expression";
+
         case "ConditionalExpression":
           return key === "test";
 
diff --git a/tests/format/typescript/instantiation-expression/17714.ts b/tests/format/typescript/instantiation-expression/17714.ts
new file mode 100644
index 000000000..a5738b907
--- /dev/null
+++ b/tests/format/typescript/instantiation-expression/17714.ts
@@ -0,0 +1 @@
+void (<_T extends never>() => {})<never>;
diff --git a/tests/format/typescript/instantiation-expression/__snapshots__/format.test.js.snap b/tests/format/typescript/instantiation-expression/__snapshots__/format.test.js.snap
index dcfe21b6e..d3adf97ad 100644
--- a/tests/format/typescript/instantiation-expression/__snapshots__/format.test.js.snap
+++ b/tests/format/typescript/instantiation-expression/__snapshots__/format.test.js.snap
@@ -1,5 +1,19 @@
 // Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
+exports[`17714.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+void (<_T extends never>() => {})<never>;
+
+=====================================output=====================================
+void (<_T extends never>() => {})<never>;
+
+================================================================================
+`;
+
 exports[`basic.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript"]