Merge pull request #2316 from andrewimm/development

Let dead code elimination run over exported functions

packages/babel-plugin-dead-code-elimination/src/index.js

@@ -21,6 +21,7 @@ export default function ({ Plugin, types: t }) {
       var binding = scope.getBinding(node.name);
       if (!binding || binding.references > 1 || !binding.constant) return;
       if (binding.kind === "param" || binding.kind === "module") return;
+      if (t.isExportDeclaration(binding.path.parent)) return;
 
       var replacement = binding.path.node;
       if (t.isVariableDeclarator(replacement)) {