From 011079fb6bd6936cac3646594274414d1fee880a Mon Sep 17 00:00:00 2001
From: Boopathi Rajaa <me@boopathi.in>
Date: Mon, 11 Dec 2017 00:00:54 +0100
Subject: [PATCH] fix(dce): don't remove toplevel classes

Apply the same trick we use in mangler to detect toplevel classes
---
 .../__tests__/fixtures/toplevel-class/actual.js           | 1 +
 .../__tests__/fixtures/toplevel-class/expected.js         | 1 +
 .../src/index.js                                          | 8 ++++++++
 3 files changed, 10 insertions(+)
 create mode 100644 packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/actual.js
 create mode 100644 packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/expected.js

diff --git a/packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/actual.js b/packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/actual.js
new file mode 100644
index 000000000..4e6a6de65
--- /dev/null
+++ b/packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/actual.js
@@ -0,0 +1 @@
+class Foo {}
diff --git a/packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/expected.js b/packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/expected.js
new file mode 100644
index 000000000..f72abf33f
--- /dev/null
+++ b/packages/babel-plugin-minify-dead-code-elimination/__tests__/fixtures/toplevel-class/expected.js
@@ -0,0 +1 @@
+class Foo {}
\ No newline at end of file
diff --git a/packages/babel-plugin-minify-dead-code-elimination/src/index.js b/packages/babel-plugin-minify-dead-code-elimination/src/index.js
index 25fe626eb..037fccefa 100644
--- a/packages/babel-plugin-minify-dead-code-elimination/src/index.js
+++ b/packages/babel-plugin-minify-dead-code-elimination/src/index.js
@@ -208,6 +208,14 @@ module.exports = ({ types: t, traverse }) => {
             ) {
               // `bar(function foo() {})` foo is not referenced but it's used.
               continue;
+            } else if (
+              // ClassDeclaration has binding in two scopes
+              //   1. The scope in which it is declared
+              //   2. The class's own scope
+              binding.path.isClassDeclaration() &&
+              binding.path === scope.path
+            ) {
+              continue;
             }
 
             const mutations = [];