From 565106dd63ef363771c2ae122c81652e3c755df2 Mon Sep 17 00:00:00 2001
From: Kevin Gibbons <bakkot@gmail.com>
Date: Tue, 18 Apr 2017 13:28:33 -0700
Subject: [PATCH] Add parentheses for assignment as body of arrow (#1326)

---
 src/fast-path.js                                   | 2 +-
 tests/arrows/__snapshots__/jsfmt.spec.js.snap      | 4 ++++
 tests/arrows/arrow_function_expression.js          | 2 ++
 tests/flow/arrays/__snapshots__/jsfmt.spec.js.snap | 2 +-
 4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/fast-path.js b/src/fast-path.js
index ad009a98e8dc..530003b10389 100644
--- a/src/fast-path.js
+++ b/src/fast-path.js
@@ -440,7 +440,7 @@ FPp.needsParens = function(assumeExpressionContext) {
 
     case "AssignmentExpression":
       if (parent.type === "ArrowFunctionExpression" && parent.body === node) {
-        return node.left.type === "ObjectPattern";
+        return true;
       } else if (
         parent.type === "ForStatement" &&
         (parent.init === node || parent.update === node)
diff --git a/tests/arrows/__snapshots__/jsfmt.spec.js.snap b/tests/arrows/__snapshots__/jsfmt.spec.js.snap
index 414571800b3f..823e4548d9ee 100644
--- a/tests/arrows/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/arrows/__snapshots__/jsfmt.spec.js.snap
@@ -31,6 +31,8 @@ x => ({}().b);
 a::(b => c);
 a = b => c;
 a = (b?) => c;
+x => (y = z);
+x => (y += z);
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 (a => {}).length;
 typeof (() => {});
@@ -63,6 +65,8 @@ x => ({}().b);
 a::(b => c);
 a = b => c;
 a = (b?) => c;
+x => (y = z);
+x => (y += z);
 
 `;
 
diff --git a/tests/arrows/arrow_function_expression.js b/tests/arrows/arrow_function_expression.js
index 3435c4174722..64e2b67608e4 100644
--- a/tests/arrows/arrow_function_expression.js
+++ b/tests/arrows/arrow_function_expression.js
@@ -28,3 +28,5 @@ x => ({}().b);
 a::(b => c);
 a = b => c;
 a = (b?) => c;
+x => (y = z);
+x => (y += z);
diff --git a/tests/flow/arrays/__snapshots__/jsfmt.spec.js.snap b/tests/flow/arrays/__snapshots__/jsfmt.spec.js.snap
index 4412f32f6072..4f77b4e22276 100644
--- a/tests/flow/arrays/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/flow/arrays/__snapshots__/jsfmt.spec.js.snap
@@ -51,7 +51,7 @@ a[1] = "...";
 
 foo(a[1]);
 var y;
-a.forEach(x => y = x);
+a.forEach(x => (y = x));
 
 // for literals, composite element type is union of individuals
 // note: test both tuple and non-tuple inferred literals