From 79d3f2e680e48949581bafd8c9302c8e29939cbb Mon Sep 17 00:00:00 2001
From: Harsh Vardhan Chauhan <harshvardhanchauhan776@gmail.com>
Date: Wed, 4 Nov 2026 12:43:04 +0530
Subject: [PATCH] Add fourslash test for JSDoc @this/@param types in JS files

Covers completions, hover, and signature help using JSDoc @this and
@param types in a JS file (see #65167).
---
 .../tests/jsdocThisAndParamTypesInJs_test.go  | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 tsc/internal/fourslash/tests/jsdocThisAndParamTypesInJs_test.go

diff --git a/tsc/internal/fourslash/tests/jsdocThisAndParamTypesInJs_test.go b/tsc/internal/fourslash/tests/jsdocThisAndParamTypesInJs_test.go
new file mode 100644
index 0000000000000..705951df4c505
--- /dev/null
+++ b/tsc/internal/fourslash/tests/jsdocThisAndParamTypesInJs_test.go
@@ -0,0 +1,57 @@
+package fourslash_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/TypeScript/tsc/internal/fourslash"
+	. "github.com/microsoft/TypeScript/tsc/internal/fourslash/tests/util"
+	"github.com/microsoft/TypeScript/tsc/internal/testutil"
+)
+
+// JSDoc `@this` and `@param` types in JS files should be used by completions, hover, and signature help.
+func TestJsdocThisAndParamTypesInJs(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `// @allowJs: true
+// @checkJs: true
+// @filename: /a.js
+/**
+ * @this {{ id: string, click: () => void }}
+ * @param {{ name: string }} p
+ */
+function h(p/*paramHover*/) {
+  this./*thisCompletions*/;
+  p./*paramCompletions*/;
+}
+
+/**
+ * @param {string} a
+ * @param {number} b
+ */
+function f(a, b) {}
+f(/*signatureHelp*/);`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+
+	f.VerifyCompletions(t, "thisCompletions", &fourslash.CompletionsExpectedList{
+		IsIncomplete: false,
+		ItemDefaults: &fourslash.CompletionsExpectedItemDefaults{
+			CommitCharacters: &DefaultCommitCharacters,
+		},
+		Items: &fourslash.CompletionsExpectedItems{
+			Exact: []fourslash.CompletionsExpectedItem{"click", "id"},
+		},
+	})
+	f.VerifyCompletions(t, "paramCompletions", &fourslash.CompletionsExpectedList{
+		IsIncomplete: false,
+		ItemDefaults: &fourslash.CompletionsExpectedItemDefaults{
+			CommitCharacters: &DefaultCommitCharacters,
+		},
+		Items: &fourslash.CompletionsExpectedItems{
+			Exact: []fourslash.CompletionsExpectedItem{"name"},
+		},
+	})
+	f.VerifyQuickInfoAt(t, "paramHover", "(parameter) p: {\n    name: string;\n}", "")
+	f.GoToMarker(t, "signatureHelp")
+	f.VerifySignatureHelp(t, fourslash.VerifySignatureHelpOptions{Text: "f(a: string, b: number): void"})
+}