minifier: invalid handling for var variable declared in switch statement

[hyp3rflow]

Describe the bug

when there is a var declaration in the default case, following case statements referencing x will be minified incorrectly.

Input code

"use strict";
const k = (() => {
switch ("") { 
    default: var x;
    case "": x; 
} 
return x;
})();

Config

{
  "jsc": {
    "parser": {
      "syntax": "ecmascript",
      "jsx": false
    },
    "target": "es2022",
    "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": false
    }
  },
  "module": {
    "type": "commonjs"
  },
  "minify": false,
  "isModule": false
}

Playground link (or link to the minimal reproduction)

https://play.swc.rs/?version=1.5.2&code=H4sIAAAAAAAAAx2MQQqAIBRE9%2F8Uw1%2FpFRS7i5hRFAb6rUC8e9bs3nswXEtEkbwFYUvhTEWww0EpDTehUbk3CSsUs0YDYWyOi6%2BHGFw%2B47G%2FC378MJvBoA7KUWpOX%2B1aafsCE2i0nmcAAAA%3D&config=H4sIAAAAAAAAA32UO5LbMAyG%2Bz2FR3WKjMscIF3OwKFJUKZDEhoC9Fqz47sHeviRNeROwocfIAEQXx%2B7XXci1%2F3afcmn%2FAy2EtT7v1hoLGwvYunAZUuuxoG7Hzd6ogkFmwhm03UhHdvaA88q2v%2Fc71dFlxAJborVlmOJYXzO6TAPFYiebGKVkC1DYfpfv7KKnxPg2p7tB8QEtrwhxpKJhaGHqgV2mJIdCMzZViXKdFJbI6GWYoKNwZuh4qDy4iNHLJLzlXqw3jj0oKBYwXE8gyaTXCIrJNdT7jNjD4fW93Ofv6nhbFOzrOSEy9wSOa0S9YiR2IRWtBIucKMGC1yL%2B10Zg6nArZZX3Qlj2ejJXwCpQLJExWbQ4s4eQeZpSx3eKmMJMrI8KlzmW7tlgV6KamIMSmWnykDlqHWzgm8Opso67Tgr3igfRQ8GQpBZUULTZ2R31JLyOAAGBUh%2FbdCmagHm%2Fgo3%2BPQg3uDfckvWB2z1yJaP25TGfMD0JkEGPqJ%2F4yCtYNzGVbbEZdjmrXiQ0QCvujSawesSkAfAaNK8L19mQ56HRDR9wsNjTawO1%2Fsezrb0j%2Fe%2BrOKP1aHL6NsM1yU%2F9XdazdKOjOVE3cPztorvp%2B8i%2FbnJl9jXf3MIldo2BgAA

SWC Info output

No response

Expected behavior

output code should work as expected. (k is undefined)

Actual behavior

const k = x after minified. (results in ReferenceError)

Version

1.5.2

Additional context

Switching the order of case statements makes output work as expected.

[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.