Tree shaking fails for my project

[vladbat00]

Hi everyone! I've just tried to test tree shaking on my project, but unfortunately it fails.
Steps to reproduce the error:

git clone git@github.com:Gitlings/platformio.git
cd platformio/frontend
yarn install
yarn parcel build index.html --experimental-scope-hoisting

Here's what I get:

yarn run v1.9.4
$ /var/www/platformio/frontend/node_modules/.bin/parcel build index.html --experimental-scope-hoisting
⠋ Building...lscpu: failed to determine number of CPUs: /sys/devices/system/cpu/possible: No such file or directory
🚨  Unexpected token, expected ; (2:19)
    at Parser.pp$5.raise (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:4454:13)
    at Parser.pp.unexpected (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:1761:8)
    at Parser.pp.semicolon (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:1742:38)
    at Parser.pp$1.parseVarStatement (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:2170:8)
    at Parser.pp$1.parseStatement (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:1861:19)
    at Parser.pp$1.parseBlockBody (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:2268:21)
    at Parser.pp$1.parseTopLevel (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:1778:8)
    at Parser.parse (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:1673:17)
    at Object.parse (/var/www/platformio/frontend/node_modules/babylon/lib/index.js:7305:37)
    at JSConcatPackager.parse (/var/www/platformio/frontend/node_modules/parcel-bundler/src/packagers/JSConcatPackager.js:346:23)
    at JSConcatPackager.addDeps (/var/www/platformio/frontend/node_modules/parcel-bundler/src/packagers/JSConcatPackager.js:236:25)
    at JSConcatPackager.addDeps (/var/www/platformio/frontend/node_modules/parcel-bundler/src/packagers/JSConcatPackager.js:225:25)
    at JSConcatPackager.addDeps (/var/www/platformio/frontend/node_modules/parcel-bundler/src/packagers/JSConcatPackager.js:225:25)
    at JSConcatPackager.end (/var/www/platformio/frontend/node_modules/parcel-bundler/src/packagers/JSConcatPackager.js:442:36)
    at Bundle._package (/var/www/platformio/frontend/node_modules/parcel-bundler/src/Bundle.js:199:20)
    at <anonymous>
error Command failed with exit code 1.

Sorry for a little bean mean description. Would be glad to help with any other information

Software	Version(s)
Parcel	1.9.7
Node	9.11.1
Yarn	1.9.4
Operating System	Debian GNU/Linux 8 (jessie)

[vladbat00]

Oh, inserting some logging statements inside babylon lib, I've found out that it fails on my frontend/gui/PlayerInfoBar.vue file.
Seems to be a bug that this PR tries to address: #1735

[lukaszsamson]

Stumbled into this in my project. I took a look at the code that crashes babylon. It seems sometimes bad variable names are generated like

var $lRJ$exports={};$parcel$require("l/RJ","vue-property-decorator");var $lRJ$var$_typeof="function"==typeof Symbol&&"
(...)
var $l/RJ$exports = {};

or

var $hAc$exports={};$parcel$require("h/ac","vue-property-decorator");var $hAc$var$_createClass=function(){function e(
(...)
var $h/ac$exports = {};

Fortunately there is a simple workaround - changing the imported file name, e.g.
it was failing for ./src/Entries.vue and changing file name to ./src/EntriesTable.vue made it work.