Mangling sometimes reuses and attempts to re-declare symbols used in imports

[thebanjomatic]

Describe the bug

I encountered this problem while trying to minify a file from lodash. This ultimately fails my build with the following error:

Module parse failed: Identifier 'o' has already been declared (1:194)

Input code

Original Reproducer:

// https://github.com/lodash/lodash/blob/master/.internal/baseToString.js
import Symbol from './_Symbol.js';
import arrayMap from './_arrayMap.js';
import isArray from './isArray.js';
import isSymbol from './isSymbol.js';

/** Used as references for various `Number` constants. */
var INFINITY = 1 / 0;

/** Used to convert symbols to primitives and strings. */
var symbolProto = Symbol ? Symbol.prototype : undefined,
    symbolToString = symbolProto ? symbolProto.toString : undefined;

/**
 * The base implementation of `_.toString` which doesn't convert nullish
 * values to empty strings.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 */
function baseToString(value) {
  // Exit early for strings to avoid a performance hit in some environments.
  if (typeof value == 'string') {
    return value;
  }
  if (isArray(value)) {
    // Recursively convert values (susceptible to call stack limits).
    return arrayMap(value, baseToString) + '';
  }
  if (isSymbol(value)) {
    return symbolToString ? symbolToString.call(value) : '';
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
}

export default baseToString;

Minimal Reproducer:

import Foo from './foo.js';

export const Bar = Foo;

function someRecursiveFunction(value) {
  return value.map(someRecursiveFunction);
}

export default someRecursiveFunction;

Config

{
  "jsc": {
    "parser": {
      "syntax": "ecmascript",
      "jsx": false
    },
    "target": "es2015",
    "loose": false,
    "minify": {
      "compress": {
        "arguments": false,
        "arrows": true,
        "booleans": true,
        "booleans_as_integers": false,
        "collapse_vars": true,
        "comparisons": true,
        "computed_props": true,
        "conditionals": true,
        "dead_code": true,
        "directives": true,
        "drop_console": false,
        "drop_debugger": true,
        "evaluate": true,
        "expression": false,
        "hoist_funs": false,
        "hoist_props": true,
        "hoist_vars": false,
        "if_return": true,
        "join_vars": true,
        "keep_classnames": false,
        "keep_fargs": true,
        "keep_fnames": false,
        "keep_infinity": false,
        "loops": true,
        "negate_iife": true,
        "properties": true,
        "reduce_funcs": false,
        "reduce_vars": false,
        "side_effects": true,
        "switches": true,
        "typeofs": true,
        "unsafe": false,
        "unsafe_arrows": false,
        "unsafe_comps": false,
        "unsafe_Function": false,
        "unsafe_math": false,
        "unsafe_symbols": false,
        "unsafe_methods": false,
        "unsafe_proto": false,
        "unsafe_regexp": false,
        "unsafe_undefined": false,
        "unused": true,
        "const_to_let": true,
        "pristine_globals": true
      },
      "mangle": {
        "toplevel": false,
        "keep_classnames": false,
        "keep_fnames": false,
        "keep_private_props": false,
        "ie8": false,
        "safari10": false
      }
    }
  },
  "module": {
    "type": "es6"
  },
  "minify": false,
  "isModule": true
}

Playground link

https://play.swc.rs/?version=1.3.66&code=H4sIAAAAAAAAA11UTW%2FaQBS8I%2FEf5hQDTUx6JUKkh1biUFQl9JBTWMxz2dbetXbXbhDiv%2FfthynAyft23rx54zGybrRxeD3UW12hNLpGlk%2Ff4zn%2FbbOn4UBGjDBGHL6L5j%2Bqr1zjpP3i62dYOt%2BCbkb2hQQbDqaTCX5a2kFYGCrJkCrIotQGnTBStxabVVtvyWxQaGWdUM7mmEyHA77HcvVtuVqu3zDHZ0zxeM3ptO%2FpiJXYMNb6UmNkLZ3seIxQO1hnpPp1wRmhP4xm7Lz3bJEe8sbX3aEhzNCqHZVS0e5%2BOAD%2FYudavwZKbr6kWlyecteDLlh68Uw2wXpP2ApLYCsrqkk54aRW0CU27%2Bf2Df7uZbHHTpNVmTuvq9qqknYfmDpRtRQ2p7pxh%2FPC%2FjIAntmRTjhKB2FEjePkFBuDkPgUvNP8emIvng251iiLY6Q84SUVHPfEWkCysWWriqDf79Q7NAq8Yxy9fdMpvn5IBxKmOoQAJKF%2Brui05IygIcM3teCQYM9gqWB1TSDVSaOVtymIgywx8m%2BJ7Yri53NkkTBLA4GoPwKefOnUt6Y0J4HnBtb4QkVrLKeHRfZuJ4dHtrUFNU5uq2BWIaqKlxDFH1Q%2BcnacX83tP6w45f7KmjE%2BIctuRcUM3qpKdDfpW9wUci%2Bnd3x2Re5Tb8i2lePMRkgYPw6QRD%2FqEWzkY4a7O4z8J5cIufrQf4xjnp09MGaWWJnm5LNNH%2BFfgeMuPNPlvgz5B7QZnOmlBAAA&config=H4sIAAAAAAAAA41VwW7bMAy99ysCn3doB3QY9gG77RsExaIcZbJoiJSboMi%2Fj1bsNG1oY5cg5tMjRfKRen%2Fa7Zojtc2v3bv8lY%2FBZoJ8%2BxYLnRPbk1gaaHtLbQ4DN98W9EgT5G0kqKbLFWnY5g64suj788vrzGgiIsHCmG19SMGf72O22A8ZiO5sYhWXpYfE9Jk%2FYxnfJoBzubfvESPYtIEYSyYkhg6y5rjFGO1AYEabFS%2FTTW0OhFqICSwMzgwZBxVPLnDAJDEfUQfWmRYdKFDI0HIYQaNJLKElkvSUfCrsYF%2B6rvb5CxtGG4tlJSacakvktorXAwZi40vSSngFV2pwBefifmUGbzJwyemRd8SQVnryF0AqEC1Rsj1ofusJL3paY%2FtNZkheJMtnBRd9a1km6KSoJgSvVHaqDGQOWjczuNLCVNlWu84Mr5SPggMD3otWFNf0Frg9aEH5PAB6BZD%2BWq%2Bp6gqY2xSu4NNAbMC%2FJUvWBTaf6C0f1lE693uMGwF64AO6jQPSCsZ1OMuWOA3reEkORBrg1COFKvC4BGQAGE2s%2B%2FJBGzIe4tF0Efcfa2I%2BcLnt4d6mrs773b5kHCKMENdk%2FB8jsonK3cZJ1ctkP0wv%2FNREaWXwwsvzp2dDUnlafmtSTY%2Bu3CVUNXl9Tn40H4eWl%2BMWpAn0Z2HWQl3%2BAebXfY3kBgAA

Minimal Reproducer:
https://play.swc.rs/?version=1.3.66&code=H4sIAAAAAAAAA22NMQ7CMBAEe0v%2Bw3ZJGvMAREORB%2FADy5wlo9gXnX0REuLvBIuCIu3s7mzKK0vDzIwonDG4U2R2jzqcrbGGnj0OXGrD1Qsu32qPopbQEhdUznSjoFLTRvOPjptflCa8rAGEmkpBRy77dTycTLv2%2FXd6p%2Bh1acf%2BvfsBkO%2BxOrsAAAA%3D&config=H4sIAAAAAAAAA41VwW7bMAy99ysCn3doB3QY9gG77RsExaIcZbJoiJSboMi%2Fj1bsNG1oY5cg5tMjRfKRen%2Fa7Zojtc2v3bv8lY%2FBZoJ8%2BxYLnRPbk1gaaHtLbQ4DN98W9EgT5G0kqKbLFWnY5g64suj788vrzGgiIsHCmG19SMGf72O22A8ZiO5sYhWXpYfE9Jk%2FYxnfJoBzubfvESPYtIEYSyYkhg6y5rjFGO1AYEabFS%2FTTW0OhFqICSwMzgwZBxVPLnDAJDEfUQfWmRYdKFDI0HIYQaNJLKElkvSUfCrsYF%2B6rvb5CxtGG4tlJSacakvktorXAwZi40vSSngFV2pwBefifmUGbzJwyemRd8SQVnryF0AqEC1Rsj1ofusJL3paY%2FtNZkheJMtnBRd9a1km6KSoJgSvVHaqDGQOWjczuNLCVNlWu84Mr5SPggMD3otWFNf0Frg9aEH5PAB6BZD%2BWq%2Bp6gqY2xSu4NNAbMC%2FJUvWBTaf6C0f1lE693uMGwF64AO6jQPSCsZ1OMuWOA3reEkORBrg1COFKvC4BGQAGE2s%2B%2FJBGzIe4tF0Efcfa2I%2BcLnt4d6mrs773b5kHCKMENdk%2FB8jsonK3cZJ1ctkP0wv%2FNREaWXwwsvzp2dDUnlafmtSTY%2Bu3CVUNXl9Tn40H4eWl%2BMWpAn0Z2HWQl3%2BAebXfY3kBgAA

Expected behavior

The function should have a unique name and should not collide with the imports.

Actual behavior

The function exported as the default export has the same name as one of the imports which is invalid esm code and fails to parse both in the browser and in nodejs.

Version

1.3.68

Additional context

No response

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.