Mangler inserts wrong function name on anonymous function declaration

[hyp3rflow]

Describe the bug

After the mangling, the second return value (return value of var he)'s logic becomes wrong.

Input code

function a() {}
var te = function() {
    function n(e) {}
    var t = null;
    return {
        init: function(e) {
            return t = new n(e);
        }
    }
}();
var he = function() {
    function n() {
        a();
    };
    var t = null;
    return {
        init: function(e) {
            return t
        }
    }
}();

Config

{
  "jsc": {
    "parser": {
      "syntax": "ecmascript",
      "jsx": false
    },
    "target": "es5",
    "loose": false,
    "minify": {
      "compress": false,
      "mangle": {
        "toplevel": false,
        "keep_classnames": false,
        "keep_fnames": false,
        "keep_private_props": false,
        "ie8": false,
        "safari10": false
      }
    }
  },
  "module": {
    "type": "commonjs"
  },
  "minify": false,
  "isModule": true
}

Playground link

https://play.swc.rs/?version=1.3.12&code=H4sIAAAAAAAAA62OMQ6AIAxFd07REa4g8TDElEhCakJAB8PdhYrKYOJix9ff128TTdEtBEYq2LNYTYCIMIJti4oFlLkAkESOVsjxkqbkvWYSMKZA7aaOIxeHR4eq23UHbMGN7foOnF%2ByyLLA%2Bmz%2B6tbrjWyqrP9u%2B9rwALbE1g9NAQAA&config=H4sIAAAAAAAAA22OSwrDMAxE76J1Fu2iUHKHnqEIVw5O%2FRGSExqC714b8qHQlYZ5g3grjGqgX4FRlKQlXWLGD%2FRAJqAacZyhq7NaWfRKpYOMMlBuE71V5lNS2mgHwUVnl%2FbJpMBCqifCOHhqKCf2NJM%2F0JuIn8ajasRA%2BtvbPx2LmzFTvYlP5Oh%2BZEWL4q6X3btU85Be02awcL3NMaQ4KpTTfP%2Blj22dZaLyBbcl34krAQAA

Expected behavior

The init function in the he variable's logic should be same as before.
return t should reference variable inside he, not the function itself.

Actual behavior

return t reference the function itself.

Version

1.3.12

Additional context

I think this result occurs in very tricky situation.
If you rename the function init to another or remove some lines, it works well :(

[kdy1]

Seems like this only happens if you specify jsc.minify on transform(). I couldn't reproduce this using the minifier test system, but I could with the transform testing system.

Also, target = ES2015 works, so I guess this is an issue of handling of span hygiene in block scoping pass.

es2015:

https://play.swc.rs/?version=1.3.14&code=H4sIAAAAAAAAA62OMQ6AIAxFd07REa4g8TDElEhCakJAB8PdhYrKYOJix9ff128TTdEtBEYq2LNYTYCIMIJti4oFlLkAkESOVsjxkqbkvWYSMKZA7aaOIxeHR4eq23UHbMGN7foOnF%2ByyLLA%2Bmz%2B6tbrjWyqrP9u%2B9rwALbE1g9NAQAA&config=H4sIAAAAAAAAA22OSwrDMAxE76J1Fk2hUHKHnqEIVwlO%2FRGSExqC714b8qHQlYZ5g3grjGqgW4FRlKQmXULCD3RAxqMasZygKbNS9eiUcgMJZaBUJ3q9tLeCXYxK26ABb4Ptl%2FrMRM9CqifCMDiqKEV2NJM70JuIn8ahakBP%2Btv3fzoWO2OiciOfyNL9yIo9im0vu3ou8j6%2Bps1g4XKro49hVMin%2Bf5LH9s6yUT5C%2Br5sF0uAQAA

[kdy1]

I tried one more thing.

I passed

"use strict";
function a() { }
var te = function () {
    var n = function n(e) { };
    var t = null;
    return {
        init: function init(e) {
            return t = new n(e);
        }
    };
}();
var he = function () {
    var n = function n() {
        a();
    };
    ;
    var t = null;
    return {
        init: function init(e) {
            return t;
        }
    };
}();

to the name mangler, and it emitted

"use strict";
function n() {}
var r = function() {
    var n = function n(n) {};
    var r = null;
    return {
        init: function t(t) {
            return r = new n(t);
        }
    };
}();
var t = function() {
    var r = function r() {
        n();
    };
    var t = null;
    return {
        init: function n(n) {
            return t;
        }
    };
}();

which is correct. So... I think the block scoping pass broken the rule of span hygiene

[swc-bot]

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