0.16.9 throws [ERROR] The symbol has already been declared for same name nested functions

[dominikg]

export function a() {
  var b = 'b';
  var b = 'b';
  function c() {
    console.log('c');
  }
  function c() {
    console.log('c');
  }
  return c();
}

causes

✘ [ERROR] The symbol "c" has already been declared

    a.js:7:11:
      7 │   function c() {
        ╵            ^

  The symbol "c" was originally declared here:

    a.js:4:11:
      4 │   function c() {
        ╵            ^

  Duplicate lexically-declared names are not allowed in an ECMAScript module. This file is considered to be an ECMAScript module because of the "export" keyword here:

    a.js:1:0:
      1 │ export function a() {
        ╵ ~~~~~~

reproduction: https://stackblitz.com/edit/node-tl5iaw?file=a.js pnpm build

downgrading to 0.16.8 works.
running node index.js works.

the sample code is adapted from the 0.16.9 changelog example "// JavaScript allows this".

edit:
discovered via reports in @sveltejs/kit triggered by svelte generating duplicate code

[danielkita]

I have the same issue with axe-core and jspdf

[cnkbekir]

I add "devDependencies": { "esbuild": "0.16.8" } because of this problem.

[jsuryahyd]

This is happening to me in a react project, when I am using vite 4.0.2,

✘ [ERROR] The symbol "Vt" has already been declared

    node_modules/jspdf/dist/jspdf.es.min.js:236:40507:
      236 │ ...n,i),n[i+3]=255}function Vt(t,e){return 0>t?0:t>e?e:...
          ╵                             ~~

  The symbol "Vt" was originally declared here:

    node_modules/jspdf/dist/jspdf.es.min.js:236:18651:
      236 │ ...is.Ga=this.Vc=0}function Vt(t,e){return 0>t?0:t>e?e:...
          ╵                             ~~

  Duplicate lexically-declared names are not allowed in an ECMAScript
  module. This file is considered to be an ECMAScript module because
  of the "export" keyword here:

    node_modules/jspdf/dist/jspdf.es.min.js:331:35413:
      331 │ ...,e}();export default E;export{St as AcroForm,At as A...
          ╵                           ~~~~~~

/home/{user}/{project}/node_modules/esbuild/lib/main.js:1594
  let error = new Error(`${text}${summary}`);
              ^

Error: Build failed with 1 error:
node_modules/jspdf/dist/jspdf.es.min.js:236:40507: ERROR: The symbol "Vt" has already been declared
    at failureErrorWithLog (/home/jsurya/work/side/node_modules/esbuild/lib/main.js:1594:15)
    at /home/jsurya/work/side/node_modules/esbuild/lib/main.js:1050:28
    at runOnEndCallbacks (/home/jsurya/work/side/node_modules/esbuild/lib/main.js:1466:61)
    at buildResponseToResult (/home/jsurya/work/side/node_modules/esbuild/lib/main.js:1048:7)
    at /home/{user}/{project}/node_modules/esbuild/lib/main.js:1160:14
    at responseCallbacks.<computed> (/home/jsurya/work/side/node_modules/esbuild/lib/main.js:697:9)
    at handleIncomingPacket (/home/jsurya/work/side/node_modules/esbuild/lib/main.js:752:9)
    at Socket.readFromStdout (/home/jsurya/work/side/node_modules/esbuild/lib/main.js:673:7)
    at Socket.emit (node:events:390:28)
    at addChunk (node:internal/streams/readable:315:12)
    at readableAddChunk (node:internal/streams/readable:289:9)
    at Socket.Readable.push (node:internal/streams/readable:228:10)
    at Pipe.onStreamRead (node:internal/stream_base_commons:199:23) {
  errors: [
    {
      detail: undefined,
      id: '',
      location: {
        column: 40507,
        file: 'node_modules/jspdf/dist/jspdf.es.min.js',
        length: 2,
        line: 236,
        lineText: ' */function te(t,e){if(this.pos=0,this.buffer=t,this.datav=new DataView(t.buffer),this.is_with_alpha=!!e,this.bottom_up=!
        ....

[jsuryahyd]

cnkbekir
I add "devDependencies": { "esbuild": "0.16.8" } because of this problem..

this fixes the issue