From dc336a16350804e1bd991c9598ae73cec559a77e Mon Sep 17 00:00:00 2001
From: Niklas Mischkulnig <mischnic@users.noreply.github.com>
Date: Sat, 15 Dec 2018 12:05:20 +0100
Subject: [PATCH 1/3] Add test for tree shaking functions properly

---
 .../es6/tree-shaking-functions/a.js           |  2 ++
 .../es6/tree-shaking-functions/b.js           |  7 +++++++
 .../parcel-bundler/test/scope-hoisting.js     | 19 +++++++++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/a.js
 create mode 100644 packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/b.js

diff --git a/packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/a.js b/packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/a.js
new file mode 100644
index 00000000000..6ed48a716b1
--- /dev/null
+++ b/packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/a.js
@@ -0,0 +1,2 @@
+import {add} from './b';
+export default add(4, 5);
diff --git a/packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/b.js b/packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/b.js
new file mode 100644
index 00000000000..5e77acdbdd6
--- /dev/null
+++ b/packages/core/parcel-bundler/test/integration/scope-hoisting/es6/tree-shaking-functions/b.js
@@ -0,0 +1,7 @@
+export function add(a, b) {
+	return a + b;
+}
+
+export function sub(a, b) {
+	return a - b;
+}
diff --git a/packages/core/parcel-bundler/test/scope-hoisting.js b/packages/core/parcel-bundler/test/scope-hoisting.js
index 5a37bda97d8..3bc3b341408 100644
--- a/packages/core/parcel-bundler/test/scope-hoisting.js
+++ b/packages/core/parcel-bundler/test/scope-hoisting.js
@@ -433,6 +433,25 @@ describe('scope hoisting', function() {
       assert(!contents.includes('bar'));
     });
 
+    it('removes unused function exports', async function() {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          '/integration/scope-hoisting/es6/tree-shaking-functions/a.js'
+        )
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output.default, 9);
+
+      let contents = await fs.readFile(
+        path.join(__dirname, '/dist/a.js'),
+        'utf8'
+      );
+      assert(contents.includes('add'));
+      assert(!contents.includes('sub'));
+    });
+
     it('support exporting a ES6 module exported as CommonJS', async function() {
       let b = await bundle(
         path.join(

From d63a46e05b8a633d82098a8a07384f866dc82670 Mon Sep 17 00:00:00 2001
From: Niklas Mischkulnig <mischnic@users.noreply.github.com>
Date: Sat, 15 Dec 2018 12:05:54 +0100
Subject: [PATCH 2/3] Tree shake multiple es6 function exports

---
 .../core/parcel-bundler/src/scope-hoisting/shake.js | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/packages/core/parcel-bundler/src/scope-hoisting/shake.js b/packages/core/parcel-bundler/src/scope-hoisting/shake.js
index 231fd169baf..0e736e9a17a 100644
--- a/packages/core/parcel-bundler/src/scope-hoisting/shake.js
+++ b/packages/core/parcel-bundler/src/scope-hoisting/shake.js
@@ -104,7 +104,13 @@ function isUnusedWildcard(path) {
 
 function remove(path) {
   if (path.isAssignmentExpression()) {
-    if (!path.parentPath.isExpressionStatement()) {
+    if (path.parentPath.isSequenceExpression()) {
+      if (path.parent.expressions.length == 1) {
+        path.parentPath.remove();
+      } else {
+        path.remove();
+      }
+    } else if (!path.parentPath.isExpressionStatement()) {
       path.replaceWith(path.node.right);
     } else {
       path.remove();
@@ -113,11 +119,6 @@ function remove(path) {
     remove(path.parentPath.parentPath);
   } else if (isUnusedWildcard(path)) {
     remove(path.parentPath);
-  } else if (
-    path.parentPath.isSequenceExpression() &&
-    path.parent.expressions.length === 1
-  ) {
-    remove(path.parentPath);
   } else if (!path.removed) {
     path.remove();
   }

From f23550b3dfe668dd46643dbcf86b9ce22a4a2134 Mon Sep 17 00:00:00 2001
From: Niklas Mischkulnig <mischnic@users.noreply.github.com>
Date: Sat, 15 Dec 2018 13:05:24 +0100
Subject: [PATCH 3/3] Make test meaningfull

---
 packages/core/parcel-bundler/test/scope-hoisting.js | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/packages/core/parcel-bundler/test/scope-hoisting.js b/packages/core/parcel-bundler/test/scope-hoisting.js
index 3bc3b341408..139397dcf07 100644
--- a/packages/core/parcel-bundler/test/scope-hoisting.js
+++ b/packages/core/parcel-bundler/test/scope-hoisting.js
@@ -433,12 +433,13 @@ describe('scope hoisting', function() {
       assert(!contents.includes('bar'));
     });
 
-    it('removes unused function exports', async function() {
+    it('removes unused function exports when minified', async function() {
       let b = await bundle(
         path.join(
           __dirname,
           '/integration/scope-hoisting/es6/tree-shaking-functions/a.js'
-        )
+        ),
+        {minify: true}
       );
 
       let output = await run(b);
@@ -448,8 +449,8 @@ describe('scope hoisting', function() {
         path.join(__dirname, '/dist/a.js'),
         'utf8'
       );
-      assert(contents.includes('add'));
-      assert(!contents.includes('sub'));
+      assert(/.\+./.test(contents));
+      assert(!/.-./.test(contents));
     });
 
     it('support exporting a ES6 module exported as CommonJS', async function() {