From 3d0c2037c3d7d4baf309220f09e7ce83eeb8f0ee Mon Sep 17 00:00:00 2001
From: bcoe <bencoe@google.com>
Date: Sun, 17 Nov 2019 21:11:24 -0800
Subject: [PATCH 1/2] feat(optional-chaining): add tests for IterationStatement

---
 .../iteration-statement-do.js                 | 18 ++++++++++
 .../iteration-statement-for-await-of.js       | 34 +++++++++++++++++++
 .../iteration-statement-for-in.js             | 22 ++++++++++++
 .../iteration-statement-for-of-type-error.js  | 18 ++++++++++
 .../iteration-statement-for.js                | 27 +++++++++++++++
 .../iteration-statement-while.js              | 18 ++++++++++
 6 files changed, 137 insertions(+)
 create mode 100644 test/language/expressions/optional-chaining/iteration-statement-do.js
 create mode 100644 test/language/expressions/optional-chaining/iteration-statement-for-await-of.js
 create mode 100644 test/language/expressions/optional-chaining/iteration-statement-for-in.js
 create mode 100644 test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js
 create mode 100644 test/language/expressions/optional-chaining/iteration-statement-for.js
 create mode 100644 test/language/expressions/optional-chaining/iteration-statement-while.js

diff --git a/test/language/expressions/optional-chaining/iteration-statement-do.js b/test/language/expressions/optional-chaining/iteration-statement-do.js
new file mode 100644
index 0000000000..5a82cc23cd
--- /dev/null
+++ b/test/language/expressions/optional-chaining/iteration-statement-do.js
@@ -0,0 +1,18 @@
+// Copyright 2019 Google, LLC.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-OptionalExpression
+description: >
+  optional chain in test portion of do while statement
+info: |
+  IterationStatement
+    do Statement while (OptionalExpression)
+features: [optional-chaining]
+---*/
+let count = 0;
+const obj = {a: true};
+do {
+  count++;
+  break;
+} while (obj?.a);
+assert.sameValue(1, count);
diff --git a/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js b/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js
new file mode 100644
index 0000000000..e7b9ebde8b
--- /dev/null
+++ b/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js
@@ -0,0 +1,34 @@
+// Copyright 2019 Google, LLC.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-OptionalExpression
+description: >
+  optional chain RHS of for await statement
+info: |
+  IterationStatement
+    for await (LeftHandSideExpression of AssignmentExpression) Statement
+features: [optional-chaining]
+---*/
+const obj = {
+  iterable: {
+    [Symbol.asyncIterator]() {
+      return {
+        i: 0,
+        next() {
+          if (this.i < 3) {
+            return Promise.resolve({ value: this.i++, done: false });
+          }
+          return Promise.resolve({ done: true });
+        }
+      };
+    }
+  }
+};
+async function checkAssertions() {
+  let count = 0;
+  for await (const num of obj?.iterable) {
+    count += num;
+  }
+  assert.sameValue(3, count);
+}
+checkAssertions().then($DONE, $DONE);
diff --git a/test/language/expressions/optional-chaining/iteration-statement-for-in.js b/test/language/expressions/optional-chaining/iteration-statement-for-in.js
new file mode 100644
index 0000000000..2823b8053b
--- /dev/null
+++ b/test/language/expressions/optional-chaining/iteration-statement-for-in.js
@@ -0,0 +1,22 @@
+// Copyright 2019 Google, LLC.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-OptionalExpression
+description: >
+  optional chain in test portion of do while statement
+info: |
+  IterationStatement
+    for (LeftHandSideExpression in Expression) Statement
+features: [optional-chaining]
+---*/
+const obj = {
+  inner: {
+    a: 1,
+    b: 2
+  }
+};
+let str = '';
+for (const key in obj?.inner) {
+  str += key;
+}
+assert.sameValue('ab', str);
diff --git a/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js b/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js
new file mode 100644
index 0000000000..080d19c3a9
--- /dev/null
+++ b/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js
@@ -0,0 +1,18 @@
+// Copyright 2019 Google, LLC.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-OptionalExpression
+description: >
+  optional chain returning undefined in RHS of for of statement
+info: |
+  IterationStatement
+    for (LeftHandSideExpression of Expression) Statement
+features: [optional-chaining]
+---*/
+
+assert.throws(TypeError, function() {
+  const obj = undefined;
+  for (const key of obj?.a) {
+    str += key;
+  }
+});
diff --git a/test/language/expressions/optional-chaining/iteration-statement-for.js b/test/language/expressions/optional-chaining/iteration-statement-for.js
new file mode 100644
index 0000000000..34e6b8e3e1
--- /dev/null
+++ b/test/language/expressions/optional-chaining/iteration-statement-for.js
@@ -0,0 +1,27 @@
+// Copyright 2019 Google, LLC.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-OptionalExpression
+description: >
+  optional chain in init/test/update of for statement
+info: |
+  IterationStatement
+    for (Expression; Expression; Expression) Statement
+features: [optional-chaining]
+---*/
+
+// OptionalExpression in test.
+let count;
+const obj = {a: true};
+for (count = 0; obj?.a; count++) {
+  if (count > 0) break;
+}
+assert.sameValue(1, count);
+
+// OptionalExpression in init/test/update.
+let count2 = 0;
+const obj2 = undefined;
+for (obj?.a; obj2?.a; obj?.a) {
+  count2++;
+}
+assert.sameValue(0, count2);
diff --git a/test/language/expressions/optional-chaining/iteration-statement-while.js b/test/language/expressions/optional-chaining/iteration-statement-while.js
new file mode 100644
index 0000000000..80fffa9296
--- /dev/null
+++ b/test/language/expressions/optional-chaining/iteration-statement-while.js
@@ -0,0 +1,18 @@
+// Copyright 2019 Google, LLC.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: prod-OptionalExpression
+description: >
+  optional chain in test portion of while statement
+info: |
+  IterationStatement
+    while (Expression) Statement
+features: [optional-chaining]
+---*/
+let count = 0;
+const obj = {a: true};
+while (obj?.a) {
+  count++;
+  break;
+}
+assert.sameValue(1, count);

From 5babea278043dfc6029726769653b8c3a733272d Mon Sep 17 00:00:00 2001
From: bcoe <bencoe@google.com>
Date: Mon, 18 Nov 2019 20:44:34 -0800
Subject: [PATCH 2/2] chore: added a few more examples based on code review

---
 .../iteration-statement-for-await-of.js       |  1 +
 .../iteration-statement-for-of-type-error.js  | 18 ++++++++++----
 .../iteration-statement-for.js                | 24 +++++++++++++++----
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js b/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js
index e7b9ebde8b..6d414965ab 100644
--- a/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js
+++ b/test/language/expressions/optional-chaining/iteration-statement-for-await-of.js
@@ -8,6 +8,7 @@ info: |
   IterationStatement
     for await (LeftHandSideExpression of AssignmentExpression) Statement
 features: [optional-chaining]
+flags: [async]
 ---*/
 const obj = {
   iterable: {
diff --git a/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js b/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js
index 080d19c3a9..3cd18cd48f 100644
--- a/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js
+++ b/test/language/expressions/optional-chaining/iteration-statement-for-of-type-error.js
@@ -11,8 +11,18 @@ features: [optional-chaining]
 ---*/
 
 assert.throws(TypeError, function() {
-  const obj = undefined;
-  for (const key of obj?.a) {
-    str += key;
-  }
+  for (const key of {}?.a) ;
+});
+
+assert.throws(TypeError, function() {
+  for (const key of {}?.a) {}
+});
+
+const obj = undefined;
+assert.throws(TypeError, function() {
+  for (const key of obj?.a) {}
+});
+
+assert.throws(TypeError, function() {
+  for (const key of obj?.a);
 });
diff --git a/test/language/expressions/optional-chaining/iteration-statement-for.js b/test/language/expressions/optional-chaining/iteration-statement-for.js
index 34e6b8e3e1..c6d78a3181 100644
--- a/test/language/expressions/optional-chaining/iteration-statement-for.js
+++ b/test/language/expressions/optional-chaining/iteration-statement-for.js
@@ -16,12 +16,28 @@ const obj = {a: true};
 for (count = 0; obj?.a; count++) {
   if (count > 0) break;
 }
-assert.sameValue(1, count);
+assert.sameValue(count, 1);
 
 // OptionalExpression in init/test/update.
 let count2 = 0;
 const obj2 = undefined;
-for (obj?.a; obj2?.a; obj?.a) {
-  count2++;
+
+for (obj?.a; obj2?.a; obj?.a) { count2++; }
+assert.sameValue(count2, 0);
+
+for (obj?.a; undefined?.a; obj?.a) { count2++; }
+assert.sameValue(count2, 0);
+
+// Short-circuiting
+let touched = 0;
+const obj3 = {
+  get a() {
+    count++;
+    return undefined; // explicit for clarity
+  }
+};
+for (count = 0; true; obj3?.a?.[touched++]) {
+  if (count > 0) { break; }
 }
-assert.sameValue(0, count2);
+assert.sameValue(count, 1);
+assert.sameValue(touched, 0);