From abbeb266b521be5530eca26c466161f76678969d Mon Sep 17 00:00:00 2001
From: kzc <zaxxon2011@gmail.com>
Date: Tue, 10 Jan 2017 14:19:32 -0500
Subject: [PATCH] [ES6] output parens for yield when parented by AST_Dot or
 AST_Sub (#1419)

---
 lib/output.js          |  6 ++++++
 test/compress/yield.js | 28 +++++++++++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/output.js b/lib/output.js
index c0b5d7df..79165618 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -686,6 +686,12 @@ function OutputStream(options) {
         // -(yield 4)
         if (p instanceof AST_Unary)
             return true;
+        // (yield x).foo
+        if (p instanceof AST_Dot && p.expression === this)
+            return true;
+        // (yield x)['foo']
+        if (p instanceof AST_Sub && p.expression === this)
+            return true;
     });
 
     PARENS(AST_PropAccess, function(output){
diff --git a/test/compress/yield.js b/test/compress/yield.js
index 4f28b647..d1e7ece3 100644
--- a/test/compress/yield.js
+++ b/test/compress/yield.js
@@ -163,4 +163,30 @@ empty_generator_as_parameter_without_side_effects: {
         evaluate(GeneratorPrototype);
     }
     expect_exact: "var GeneratorPrototype=Object.getPrototypeOf(Object.getPrototypeOf(function*(){}()));evaluate(GeneratorPrototype);"
-}
\ No newline at end of file
+}
+
+yield_dot: {
+    options = {
+    }
+    input: {
+        function* foo(){
+            yield x.foo;
+            (yield x).foo;
+            yield (yield obj.foo()).bar();
+        }
+    }
+    expect_exact: "function*foo(){yield x.foo;(yield x).foo;yield(yield obj.foo()).bar()}"
+}
+
+yield_sub: {
+    options = {
+    }
+    input: {
+        function* foo(){
+            yield x['foo'];
+            (yield x)['foo'];
+            yield (yield obj.foo())['bar']();
+        }
+    }
+    expect_exact: 'function*foo(){yield x["foo"];(yield x)["foo"];yield(yield obj.foo())["bar"]()}'
+}