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minifier: inlining arithmetic assignment expression can result in different output #8923

Closed
hyp3rflow opened this issue May 6, 2024 · 1 comment · Fixed by #8929
Closed

minifier: inlining arithmetic assignment expression can result in different output #8923

hyp3rflow opened this issue May 6, 2024 · 1 comment · Fixed by #8929
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@kdy1
Labels
C-bug
Milestone
v1.5.5

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@hyp3rflow
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Describe the bug

Changing x *= y to x = y * x can make different result if expression y change the value of x.

Input code

"use strict";
const k = (() => {
    let x = '';
    x *= x-- / 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=H4sIAAAAAAAAAx3IQQqAIBBG4b2n+HHjGEgHGOwy4iIKA2eEgejuiW/3PT+kQrSfRT278jRRXMggisgHXofZXRU2Zwi8bNgyLCXsMMZaverobdJ9kSL/sQJtalcAAAA=&config=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

SWC Info output

No response

Expected behavior

k is -0

Actual behavior

k is 0

Version

1.5.2

Additional context

No response
@hyp3rflow hyp3rflow added the C-bug label May 6, 2024
@kdy1 kdy1 self-assigned this May 7, 2024
@kdy1 kdy1 added this to the Planned milestone May 7, 2024
@kdy1 kdy1 mentioned this issue May 7, 2024
Merged
kdy1 added a commit that referenced this issue May 7, 2024
@kdy1
fix(es/minifier): Consider side effects of operands of binary express…
4d4a7a9 
…ions (#8929)

**Related issue:**

 - Closes #8923
@kdy1 kdy1 closed this as completed in #8929 May 7, 2024
@kdy1 kdy1 modified the milestones: Planned, v1.5.5 May 8, 2024
@swc-bot
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swc-bot commented Jun 7, 2024

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.

@swc-project swc-project locked as resolved and limited conversation to collaborators Jun 7, 2024
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Assignees

@kdy1 kdy1

Labels
C-bug
Milestone
v1.5.5
Development

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fix(es/minifier): Consider side effects of operands of binary expressions kdy1/swc
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@kdy1 @hyp3rflow @swc-bot