From bc08f057e3ee6c1176df9b8a7bfaf74de826a8f6 Mon Sep 17 00:00:00 2001
From: Alan Pierce <alan@benchling.com>
Date: Sun, 25 Nov 2018 13:40:10 -0800
Subject: [PATCH] Fix infinite loop in flow `declare module` parsing (#359)

---
 src/parser/plugins/flow.ts |  2 ++
 test/flow-test.ts          | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/parser/plugins/flow.ts b/src/parser/plugins/flow.ts
index 03570e2e..03ee16c5 100644
--- a/src/parser/plugins/flow.ts
+++ b/src/parser/plugins/flow.ts
@@ -152,6 +152,8 @@ function flowParseDeclareModule(): void {
     if (match(tt._import)) {
       next();
       parseImport();
+    } else {
+      unexpected();
     }
   }
   expect(tt.braceR);
diff --git a/test/flow-test.ts b/test/flow-test.ts
index 8e3bfcdc..b2b25d00 100644
--- a/test/flow-test.ts
+++ b/test/flow-test.ts
@@ -1,3 +1,5 @@
+import {throws} from "assert";
+import {transform} from "../src";
 import {IMPORT_DEFAULT_PREFIX} from "./prefixes";
 import {assertResult} from "./util";
 
@@ -390,4 +392,19 @@ describe("transform flow", () => {
     `,
     );
   });
+
+  it("does not infinite loop on declare module declarations", () => {
+    throws(
+      () =>
+        transform(
+          `
+      declare module 'ReactFeatureFlags' {
+        declare module.exports: any;
+      }
+    `,
+          {transforms: ["flow"]},
+        ),
+      /SyntaxError: Unexpected token \(3:9\)/,
+    );
+  });
 });