From 945556d5bfd4a7f88140ad4b397bede6dde2db7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Fri, 14 Feb 2025 21:10:56 +0100
Subject: [PATCH] Treat functions with `@type` tags on parameters as typed in
 JS files

---
 src/compiler/checker.ts                       |  1 +
 .../jsdocTypeTagOnParameter1.symbols          | 31 +++++++++++
 .../reference/jsdocTypeTagOnParameter1.types  | 55 +++++++++++++++++++
 .../jsdoc/jsdocTypeTagOnParameter1.ts         | 21 +++++++
 4 files changed, 108 insertions(+)
 create mode 100644 tests/baselines/reference/jsdocTypeTagOnParameter1.symbols
 create mode 100644 tests/baselines/reference/jsdocTypeTagOnParameter1.types
 create mode 100644 tests/cases/conformance/jsdoc/jsdocTypeTagOnParameter1.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index d9d1950d6b675..15435a9b75a48 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -15504,6 +15504,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 isInJSFile(declaration) &&
                 isValueSignatureDeclaration(declaration) &&
                 !hasJSDocParameterTags(declaration) &&
+                !some(declaration.parameters, p => !!getJSDocType(p)) &&
                 !getJSDocType(declaration);
             if (isUntypedSignatureInJSFile) {
                 flags |= SignatureFlags.IsUntypedSignatureInJSFile;
diff --git a/tests/baselines/reference/jsdocTypeTagOnParameter1.symbols b/tests/baselines/reference/jsdocTypeTagOnParameter1.symbols
new file mode 100644
index 0000000000000..3f6099b16adc2
--- /dev/null
+++ b/tests/baselines/reference/jsdocTypeTagOnParameter1.symbols
@@ -0,0 +1,31 @@
+//// [tests/cases/conformance/jsdoc/jsdocTypeTagOnParameter1.ts] ////
+
+=== /index.js ===
+function repeat(
+>repeat : Symbol(repeat, Decl(index.js, 0, 0))
+
+	/** @type {string} */ message,
+>message : Symbol(message, Decl(index.js, 0, 16))
+
+	/** @type {number} */ times,
+>times : Symbol(times, Decl(index.js, 1, 31))
+
+) {
+	return Array(times).fill(message).join(` `);
+>Array(times).fill(message).join : Symbol(Array.join, Decl(lib.es5.d.ts, --, --))
+>Array(times).fill : Symbol(Array.fill, Decl(lib.es2015.core.d.ts, --, --))
+>Array : Symbol(Array, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --) ... and 4 more)
+>times : Symbol(times, Decl(index.js, 1, 31))
+>fill : Symbol(Array.fill, Decl(lib.es2015.core.d.ts, --, --))
+>message : Symbol(message, Decl(index.js, 0, 16))
+>join : Symbol(Array.join, Decl(lib.es5.d.ts, --, --))
+}
+
+/** @type {Parameters<typeof repeat>[0]} */
+const message = `hello`;
+>message : Symbol(message, Decl(index.js, 8, 5))
+
+/** @type {Parameters<typeof repeat>[1]} */
+const times = 3;
+>times : Symbol(times, Decl(index.js, 11, 5))
+
diff --git a/tests/baselines/reference/jsdocTypeTagOnParameter1.types b/tests/baselines/reference/jsdocTypeTagOnParameter1.types
new file mode 100644
index 0000000000000..5b3b0ea8855af
--- /dev/null
+++ b/tests/baselines/reference/jsdocTypeTagOnParameter1.types
@@ -0,0 +1,55 @@
+//// [tests/cases/conformance/jsdoc/jsdocTypeTagOnParameter1.ts] ////
+
+=== /index.js ===
+function repeat(
+>repeat : (message: string, times: number) => string
+>       : ^       ^^      ^^     ^^      ^^^^^^^^^^^
+
+	/** @type {string} */ message,
+>message : string
+>        : ^^^^^^
+
+	/** @type {number} */ times,
+>times : number
+>      : ^^^^^^
+
+) {
+	return Array(times).fill(message).join(` `);
+>Array(times).fill(message).join(` `) : string
+>                                     : ^^^^^^
+>Array(times).fill(message).join : (separator?: string) => string
+>                                : ^         ^^^      ^^^^^      
+>Array(times).fill(message) : any[]
+>                           : ^^^^^
+>Array(times).fill : (value: any, start?: number, end?: number) => any[]
+>                  : ^     ^^^^^^^     ^^^      ^^   ^^^      ^^^^^^^^^^
+>Array(times) : any[]
+>             : ^^^^^
+>Array : ArrayConstructor
+>      : ^^^^^^^^^^^^^^^^
+>times : number
+>      : ^^^^^^
+>fill : (value: any, start?: number, end?: number) => any[]
+>     : ^     ^^^^^^^     ^^^      ^^   ^^^      ^^^^^^^^^^
+>message : string
+>        : ^^^^^^
+>join : (separator?: string) => string
+>     : ^         ^^^      ^^^^^      
+>` ` : " "
+>    : ^^^
+}
+
+/** @type {Parameters<typeof repeat>[0]} */
+const message = `hello`;
+>message : string
+>        : ^^^^^^
+>`hello` : "hello"
+>        : ^^^^^^^
+
+/** @type {Parameters<typeof repeat>[1]} */
+const times = 3;
+>times : number
+>      : ^^^^^^
+>3 : 3
+>  : ^
+
diff --git a/tests/cases/conformance/jsdoc/jsdocTypeTagOnParameter1.ts b/tests/cases/conformance/jsdoc/jsdocTypeTagOnParameter1.ts
new file mode 100644
index 0000000000000..3dec04c0432a2
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/jsdocTypeTagOnParameter1.ts
@@ -0,0 +1,21 @@
+// @strict: true
+// @lib: esnext
+// @allowJS: true
+// @checkJs: true
+// @noEmit: true
+
+// https://github.com/microsoft/TypeScript/issues/61172
+
+// @filename: /index.js
+function repeat(
+	/** @type {string} */ message,
+	/** @type {number} */ times,
+) {
+	return Array(times).fill(message).join(` `);
+}
+
+/** @type {Parameters<typeof repeat>[0]} */
+const message = `hello`;
+
+/** @type {Parameters<typeof repeat>[1]} */
+const times = 3;