Incorrect compression: compound assignment with inc/dec in template string

[onetw012]

Describe the bug

SWC with "compress" option transpiles some expressions involving assignment, increment/decrement operator and template literal into invalid JS for ES2015+ targets. The occurrence of this issue appears to have started since v1.3.27.

Input code

let id = 0;

function getId() {
    id = id % 9999;
    return `${id++}`
}

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": true,
        "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,
        "passes": 2
      },
      "mangle": false
    }
  },
  "module": {
    "type": "es6"
  },
  "minify": false,
  "isModule": false
}

Playground link

https://play.swc.rs/?version=1.3.70&code=H4sIAAAAAAAAA8tJLVHITFGwVTCw5uJKK81LLsnMz1NITy3xTNHQVKjmUgACsDyQUFWwBAJrsFhRaklpUZ5Cgkp1Zoq2dm0CVy0AFqXyMEoAAAA%3D&config=H4sIAAAAAAAAA32UwW7bMAyG732KwOcdtgLdYQ%2Bw255BUCTKUSaLhkilMYq8%2B2jZSbOGzs3mx5%2BUSIofL7tddyTX%2Fdp9yKf8jLYQlNu%2FWGjKbM9i6cANllyJI3ffrvRIMwo2ETTTZSEd29IDNxW9fv%2Fxtiq6hEhwVay2IeYYpvucDoexANGdTawSsg6Qmf7Xr6zg%2Bwy41Hv7HjGBzU%2BIsWRiZuihaIEdpmRHAnOyRYkyn9SWSKilmGFl8GYsOKo8%2B8gRs%2BR8pB6sNw49KCgWcBxPoMkkl8gyyfWU%2BzTsYV%2F7vvX5ixpONlXLSk44t5bIaR%2FZASOxCTVrFVzgRgkWuNb2qzIGU4BrUTIeMeaNlvwFkAIkS5TtAFrc5hFknLbU4aky5iATy5PCZby1W2bopaYmxqAUdq4MFI5aMwv46mCurNOOs%2BKN8lH0YCAEGRUlNL1HdgctKU8jYFCA9NcGbagWYG6PcIPP7%2BEJ%2Fi235GW%2BNjwGy4dtStOwx%2FQkwQB8QP%2FEQVrBuI2LLInzuM1r9iCjAV51qdTA4w6QB8BoUluXD7Mhz0Mimj7hXt0So8x5a%2BLrarvcdvNgc%2F%2B5A5b1%2FLI6dAP62uC6%2BOemL%2Bv6Z%2FfpdN3Mt9t0kf5clUvYyz%2FC6tcBRQYAAA%3D%3D

Expected behavior

Transpilation to ES5 returns syntactically correct Javascript

var getId=function(){return id%=9999,"".concat(id++)},id=0;

resembling, for instance, Terser with ecma2015 target

let id=0;function getId(){return id%=9999,""+id++}

Actual behavior

It tries to combine compound assignment with increment operator in one expression inside template string:

let id = 0;
function getId() {
    return `${id %= 9999++}`;
}

Version

1.3.70

Additional context

The example above can be reduced to something like:

function add11(a) {
    a += 10
    return `${a++}`
}

which is transpiled into:

function add11(a) {
    return `${a += 10++}`;
}

where 10++ leads to an error Uncaught SyntaxError: Invalid left-hand side expression in postfix operation

[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.