From 6f432d9a68cf1fc9396b97d35c4d25e07582765b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Mon, 30 Jun 2025 11:24:36 +0200
Subject: [PATCH] Fixed crash on `ConstructSignature` when computing
 interactive inlay hints

---
 src/services/inlayHints.ts                    | 10 +++
 .../inlayHintsVariableTypes3.baseline         | 69 +++++++++++++++++++
 .../fourslash/inlayHintsVariableTypes3.ts     | 20 ++++++
 3 files changed, 99 insertions(+)
 create mode 100644 tests/baselines/reference/inlayHintsVariableTypes3.baseline
 create mode 100644 tests/cases/fourslash/inlayHintsVariableTypes3.ts

diff --git a/src/services/inlayHints.ts b/src/services/inlayHints.ts
index d79def836396d..7c84d533443f5 100644
--- a/src/services/inlayHints.ts
+++ b/src/services/inlayHints.ts
@@ -44,6 +44,7 @@ import {
     isCallSignatureDeclaration,
     isConditionalTypeNode,
     isConstructorTypeNode,
+    isConstructSignatureDeclaration,
     isEnumMember,
     isExpressionWithTypeArguments,
     isFunctionDeclaration,
@@ -825,6 +826,15 @@ export function provideInlayHints(context: InlayHintsContext): InlayHint[] {
                         visitForDisplayParts(node.type);
                     }
                     break;
+                case SyntaxKind.ConstructSignature:
+                    Debug.assertNode(node, isConstructSignatureDeclaration);
+                    parts.push({ text: "new " });
+                    visitParametersAndTypeParameters(node);
+                    if (node.type) {
+                        parts.push({ text: ": " });
+                        visitForDisplayParts(node.type);
+                    }
+                    break;
                 case SyntaxKind.ArrayBindingPattern:
                     Debug.assertNode(node, isArrayBindingPattern);
                     parts.push({ text: "[" });
diff --git a/tests/baselines/reference/inlayHintsVariableTypes3.baseline b/tests/baselines/reference/inlayHintsVariableTypes3.baseline
new file mode 100644
index 0000000000000..9b43534d8c51c
--- /dev/null
+++ b/tests/baselines/reference/inlayHintsVariableTypes3.baseline
@@ -0,0 +1,69 @@
+// === Inlay Hints ===
+const div = getCtor("div");
+         ^
+{
+  "text": "",
+  "displayParts": [
+    {
+      "text": ": "
+    },
+    {
+      "text": "{"
+    },
+    {
+      "text": " "
+    },
+    {
+      "text": "new "
+    },
+    {
+      "text": "("
+    },
+    {
+      "text": ")"
+    },
+    {
+      "text": ": "
+    },
+    {
+      "text": "DivElement",
+      "span": {
+        "start": 10,
+        "length": 10
+      },
+      "file": "/tests/cases/fourslash/inlayHintsVariableTypes3.ts"
+    },
+    {
+      "text": "; "
+    },
+    {
+      "text": "prototype"
+    },
+    {
+      "text": ": "
+    },
+    {
+      "text": "DivElement",
+      "span": {
+        "start": 10,
+        "length": 10
+      },
+      "file": "/tests/cases/fourslash/inlayHintsVariableTypes3.ts"
+    },
+    {
+      "text": " "
+    },
+    {
+      "text": "}"
+    },
+    {
+      "text": " | "
+    },
+    {
+      "text": "undefined"
+    }
+  ],
+  "position": 260,
+  "kind": "Type",
+  "whitespaceBefore": true
+}
\ No newline at end of file
diff --git a/tests/cases/fourslash/inlayHintsVariableTypes3.ts b/tests/cases/fourslash/inlayHintsVariableTypes3.ts
new file mode 100644
index 0000000000000..87c15a601089b
--- /dev/null
+++ b/tests/cases/fourslash/inlayHintsVariableTypes3.ts
@@ -0,0 +1,20 @@
+/// <reference path="fourslash.ts" />
+
+// @strict: true
+// @target: esnext
+
+//// interface DivElement {}
+//// declare var DivElementCtor: {
+////   prototype: DivElement;
+////   new(): DivElement;
+//// };
+//// interface ElementMap {
+////   div: typeof DivElementCtor;
+//// }
+//// declare function getCtor<K extends keyof ElementMap>(tagName: K): ElementMap[K] | undefined;
+//// const div = getCtor("div");
+
+verify.baselineInlayHints(undefined, {
+    includeInlayVariableTypeHints: true,
+    interactiveInlayHints: true
+});