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Rust-based platform for the Web
https://swc.rs
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minifier: string concatenation with `-0` should be evaluated as concat with `0` #9010

Closed hyp3rflow closed 3 months ago

hyp3rflow commented 3 months ago

Describe the bug

According to the step 2 of Number::toString spec, both signed zero should be regarded as normal zero resulting in "0".

Currently minifier evaluates correctly with simple program like (-0).toString(), but much complex example like below is not handled correctly.

Input code

console.log(-0 + [])

Config

{
  "jsc": {
    "parser": {
      "syntax": "ecmascript",
      "jsx": false
    },
    "target": "es5",
    "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": "commonjs"
  },
  "minify": false,
  "isModule": false
}

Playground link (or link to the minimal reproduction)

https://play.swc.rs/?version=1.5.24&code=H4sIAAAAAAAAA0vOzyvOz0nVy8lP19A1UNBWiI7VBAAUpZKNFAAAAA%3D%3D&config=H4sIAAAAAAAAA42VzW7bMAyA732KwOcdtsOAYg%2Bw255BUCzKUSaJhkilCYq8%2B2jFTtOGNnYJYn78ESmSen%2FZ7boj9d2v3bv8lY%2FRFoJy%2FxYJXTLbs0g66JOlvoSRu28LPdKEvI0ETXS9kY5tGYCbFf2c1buISLCoz7IUcvCXx4A9prEA0YNMpOKvJshMn%2B1nVvBtAlzqo3yPGMHmDWIsmZAZBiia4x5jtCOBOdmieJlOaksg1EJMsDI4MxYcVZ5d4IBZYj5TB9aZHh0oKBToOZxAM5NYYpZJ0lPyadjBvg5Du%2BQv1nCysVpWYsK5XYmcVvF6wEBsfM1aCW9wpQY3OBf3q2XwpgDXkp%2Ftjhjyyp38BZAKREuUbQLNb9Pw0k9r1n7TMmQvLcsXhUt%2Fa1lmGKSoJgSvVHaqDBQO2m0WcLWHqbK9dpwZr5SPggMD3kuvKK7pLXB%2F0ILyZQT0CpD7tV7rqhsw9ylc4dNAbODfkiXrDTZrJMuHdUqXtMe4ESABH9BtKMhVMK7jIlviPK7zmh1Ia4BTVSo18LwEZAAYTWzL8qk3ZDzEoxki7j%2FWxKxwvS%2FhZPPQ5v1hXzKOEU4Q19r4P0Zkk8rZTlNXL5P9NL3wqjWllcELP75%2FejMklZfltyXVJXT1IaHWk9NbIi2UMB%2Bp%2B9Bcno97pC7Qn8X8FuP6D4cPrcHnBgAA

SWC Info output

No response

Expected behavior

console.log("0")

Actual behavior

console.log("-0")

Version

1.5.24

Additional context

No response

swc-bot commented 2 months ago

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.