From 58f9f26bb2180b3fcb74710b41a49b2e9005c6c0 Mon Sep 17 00:00:00 2001
From: Rich-Harris <richard.a.harris@gmail.com>
Date: Thu, 22 Dec 2016 11:10:55 -0500
Subject: [PATCH] support async functions (#492)

---
 src/Module.js                                     |  2 +-
 test/form/async-function-unused/_config.js        |  3 +++
 test/form/async-function-unused/_expected/amd.js  |  9 +++++++++
 test/form/async-function-unused/_expected/cjs.js  |  7 +++++++
 test/form/async-function-unused/_expected/es.js   |  5 +++++
 test/form/async-function-unused/_expected/iife.js | 10 ++++++++++
 test/form/async-function-unused/_expected/umd.js  | 13 +++++++++++++
 test/form/async-function-unused/main.js           |  3 +++
 test/form/async-function-unused/utils.js          |  7 +++++++
 9 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 test/form/async-function-unused/_config.js
 create mode 100644 test/form/async-function-unused/_expected/amd.js
 create mode 100644 test/form/async-function-unused/_expected/cjs.js
 create mode 100644 test/form/async-function-unused/_expected/es.js
 create mode 100644 test/form/async-function-unused/_expected/iife.js
 create mode 100644 test/form/async-function-unused/_expected/umd.js
 create mode 100644 test/form/async-function-unused/main.js
 create mode 100644 test/form/async-function-unused/utils.js

diff --git a/src/Module.js b/src/Module.js
index bae304f..71db738 100644
--- a/src/Module.js
+++ b/src/Module.js
@@ -16,7 +16,7 @@ import ModuleScope from './ast/scopes/ModuleScope.js';
 function tryParse ( code, comments, acornOptions, id ) {
 	try {
 		return parse( code, assign({
-			ecmaVersion: 7,
+			ecmaVersion: 8,
 			sourceType: 'module',
 			onComment: ( block, text, start, end ) => comments.push({ block, text, start, end }),
 			preserveParens: false
diff --git a/test/form/async-function-unused/_config.js b/test/form/async-function-unused/_config.js
new file mode 100644
index 0000000..7a2ae9d
--- /dev/null
+++ b/test/form/async-function-unused/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'treeshakes async functions (#492)'
+};
diff --git a/test/form/async-function-unused/_expected/amd.js b/test/form/async-function-unused/_expected/amd.js
new file mode 100644
index 0000000..2726053
--- /dev/null
+++ b/test/form/async-function-unused/_expected/amd.js
@@ -0,0 +1,9 @@
+define(function () { 'use strict';
+
+	async function foo () {
+		return 'foo';
+	}
+
+	foo().then( value => console.log( value ) );
+
+});
diff --git a/test/form/async-function-unused/_expected/cjs.js b/test/form/async-function-unused/_expected/cjs.js
new file mode 100644
index 0000000..7da9247
--- /dev/null
+++ b/test/form/async-function-unused/_expected/cjs.js
@@ -0,0 +1,7 @@
+'use strict';
+
+async function foo () {
+	return 'foo';
+}
+
+foo().then( value => console.log( value ) );
diff --git a/test/form/async-function-unused/_expected/es.js b/test/form/async-function-unused/_expected/es.js
new file mode 100644
index 0000000..f8107f9
--- /dev/null
+++ b/test/form/async-function-unused/_expected/es.js
@@ -0,0 +1,5 @@
+async function foo () {
+	return 'foo';
+}
+
+foo().then( value => console.log( value ) );
diff --git a/test/form/async-function-unused/_expected/iife.js b/test/form/async-function-unused/_expected/iife.js
new file mode 100644
index 0000000..c61e87e
--- /dev/null
+++ b/test/form/async-function-unused/_expected/iife.js
@@ -0,0 +1,10 @@
+(function () {
+	'use strict';
+
+	async function foo () {
+		return 'foo';
+	}
+
+	foo().then( value => console.log( value ) );
+
+}());
diff --git a/test/form/async-function-unused/_expected/umd.js b/test/form/async-function-unused/_expected/umd.js
new file mode 100644
index 0000000..0be18ef
--- /dev/null
+++ b/test/form/async-function-unused/_expected/umd.js
@@ -0,0 +1,13 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory() :
+	typeof define === 'function' && define.amd ? define(factory) :
+	(factory());
+}(this, (function () { 'use strict';
+
+	async function foo () {
+		return 'foo';
+	}
+
+	foo().then( value => console.log( value ) );
+
+})));
diff --git a/test/form/async-function-unused/main.js b/test/form/async-function-unused/main.js
new file mode 100644
index 0000000..e9c0b0a
--- /dev/null
+++ b/test/form/async-function-unused/main.js
@@ -0,0 +1,3 @@
+import { foo } from './utils.js';
+
+foo().then( value => console.log( value ) );
diff --git a/test/form/async-function-unused/utils.js b/test/form/async-function-unused/utils.js
new file mode 100644
index 0000000..5f2ecc7
--- /dev/null
+++ b/test/form/async-function-unused/utils.js
@@ -0,0 +1,7 @@
+export async function foo () {
+	return 'foo';
+}
+
+export async function bar () {
+	return 'bar';
+}