Cannot read property 'add' of undefined while parsing file

[kumavis]

Error during minification

Cannot read property 'add' of undefined while parsing file:

thrown here

minify/packages/babel-plugin-minify-mangle-names/src/scope-tracker.js

Line 78 in 8f9c7c0

const ref = this.references.get(parent);

while parsing this file
https://github.com/MetaMask/metamask-extension/blob/239f5f7fa60a05f3b98eb00a9bbb7d27ee48eed1/ui/helpers/utils/conversions.util.js

Expected Output

no error

Stack Trace

 /home/xyz/Development/metamask-extension/ui/helpers/utils/conversions.util.js
    at ScopeTracker.addReference (/home/xyz/Development/metamask-extension/node_modules/babel-plugin-minify-mangle-names/lib/scope-tracker.js:47:34)
    at ReferencedIdentifier (/home/xyz/Development/metamask-extension/node_modules/babel-plugin-minify-mangle-names/lib/index.js:202:26)
    at newFn (/home/xyz/Development/metamask-extension/node_modules/@babel/traverse/lib/visitors.js:218:17)
    at bfsTraverse (/home/xyz/Development/metamask-extension/node_modules/babel-plugin-minify-mangle-names/lib/bfs-traverse.js:38:43)
    at Mangler.collect (/home/xyz/Development/metamask-extension/node_modules/babel-plugin-minify-mangle-names/lib/index.js:235:7)
    at Mangler.run (/home/xyz/Development/metamask-extension/node_modules/babel-plugin-minify-mangle-names/lib/index.js:60:12)
    at PluginPass.exit (/home/xyz/Development/metamask-extension/node_modules/babel-plugin-minify-mangle-names/lib/index.js:546:19)
    at newFn (/home/xyz/Development/metamask-extension/node_modules/@babel/traverse/lib/visitors.js:177:21)
    at NodePath._call (/home/xyz/Development/metamask-extension/node_modules/@babel/traverse/lib/path/context.js:53:20)
    at NodePath.call (/home/xyz/Development/metamask-extension/node_modules/@babel/traverse/lib/path/context.js:40:17)

Configuration

module.exports = function (api) {
  api.cache(false);
  return {
    parserOpts: {
      strictMode: true,
    },
    presets: [
      '@babel/preset-typescript',
      [
        '@babel/preset-env',
        {
          targets: {
            browsers: ['chrome >= 66', 'firefox >= 68'],
          },
        },
      ],
      '@babel/preset-react',
      'babel-preset-minify',
    ],
    plugins: [
      '@babel/plugin-transform-runtime',
      '@babel/plugin-proposal-class-properties',
      '@babel/plugin-proposal-object-rest-spread',
      '@babel/plugin-proposal-optional-chaining',
      '@babel/plugin-proposal-nullish-coalescing-operator'
    ],
  };
};

[ochodek]

There is already a pull request fixing this: #1024