diff --git a/packages/compiler/ambient/scriptc-node-fallback.d.ts b/packages/compiler/ambient/scriptc-node-fallback.d.ts
index 4a67ad89b..de3efa0ee 100644
--- a/packages/compiler/ambient/scriptc-node-fallback.d.ts
+++ b/packages/compiler/ambient/scriptc-node-fallback.d.ts
@@ -770,6 +770,7 @@ interface Request {
   arrayBuffer(): Promise<ArrayBuffer>;
   bytes(): Promise<Uint8Array>;
 }
+type RequestInfo = string | URL | Request;
 interface RequestInit {
   method?: string;
   headers?:
@@ -782,7 +783,7 @@ interface RequestInit {
   signal?: AbortSignal;
 }
 declare var Request: {
-  new (input: string | URL | Request, init?: RequestInit): Request;
+  new (input: RequestInfo, init?: RequestInit): Request;
   readonly prototype: Request;
 };
 declare function fetch(input: string | URL, init?: RequestInit): Promise<Response>;
diff --git a/packages/compiler/test/ts7/program-adapter.test.ts b/packages/compiler/test/ts7/program-adapter.test.ts
index 4b00c66fd..d7540fe19 100644
--- a/packages/compiler/test/ts7/program-adapter.test.ts
+++ b/packages/compiler/test/ts7/program-adapter.test.ts
@@ -68,6 +68,26 @@ test("retains source-file BOM stripping", () => {
   }
 });
 
+test("fallback ambient resolves RequestInfo during preflight", () => {
+  const tempRoot = process.platform === "win32" ? tmpdir() : "/tmp";
+  const dir = mkdtempSync(join(tempRoot, "scriptc-request-info-"));
+  const entry = join(dir, "entry.ts");
+  writeFileSync(entry, [
+    'const target: RequestInfo = "https://example.invalid/";',
+    "console.log(typeof target);",
+  ].join("\n"));
+
+  const load = loadProgram(entry);
+  try {
+    const diagnostics = checkPreflight(load);
+    expect(diagnostics, diagnostics.map((diag) => `${diag.code}: ${diag.message}`).join("\n"))
+      .toEqual([]);
+  } finally {
+    load.dispose();
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
 test("preflight batches symbols in deferred TDZ-analysis roots", () => {
   const tempRoot = process.platform === "win32" ? tmpdir() : "/tmp";
   const dir = mkdtempSync(join(tempRoot, "scriptc-preflight-batch-"));