minify: self-reference in class with external superclass not detected as dead code

[dmichon-msft]

Describe the bug

Found another interesting dead code elimination bug in the minifier.

Replacing Dead.x with Dead -> no repro
Remove extends Unknown -> no repro

Various other expression types, e.g. new Dead() will also trigger the behavior.

Input code

someFunction(function f() {
    class Dead extends Unknown {
        m() { Dead.x; }
    }
    return 0;
})

Config

{
  "jsc": {
    "parser": {
      "syntax": "ecmascript",
      "jsx": false
    },
    "target": "es2024",
    "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,
        "passes": 0
      },
      "mangle": false
    }
  },
  "module": {
    "type": "es6"
  },
  "minify": false,
  "isModule": true
}

Link to the code that reproduces this issue

https://play.swc.rs/?version=1.15.21&code=H4sIAAAAAAAAAyvOz011K81LLsnMz9NIgzIU0jQ0Faq5FIAgOSexuFjBJTUxRSG1oiQ1L6VYITQvOy%2B%2FPA%2BqAARyQcrBivQqrBVqweIQsii1pLQoT8HAmqtWEwAwssHDawAAAA%3D%3D&config=H4sIAAAAAAAAA32US27jMAyG9zlF4HUXRTHoYg7Q3ZxBUCTKUUYPQ6TSGEXuPrTspJmG9s7mx5%2BUSIpfu%2F2%2BO6Hpfu%2B%2F%2BJN%2FBl0Qyv2fLTgm0he2dGCiRlP8QN3LjZ5wQk4HhGa6zqQjXXqgpsK317dfi6ILOSPcFIst%2BuTd%2BJjT5DgUQHywsZVD1giJ8H%2F9wkr%2BnACV%2Bmg%2F5BxApw2iNCqfCHooUmCTQ9ADgjrrIkSZTqqLxyylmGAlsGooeRB5sp58TpzzmVrQVplsQUC%2BgCF%2FBknGuViWkK8n3KdhC4fa963PP9Rw1qFqEnLCpbWETytEPWaPpFxNUglnuFKDGS7F%2Fan0ThWgWtKz7pR9WunJXwCuQNCISUeQ4jYPx%2FO0pnabSp8cjyyNAuf5lm6ZoOeiKu%2BdUNmpMlDIS90sYKuBqbJGOs6CV8qH3oIC53hWhND46ckcpaQ0DpCdALi%2F2klTNQN1f4UrfHoQG%2FiDb0nygC0eUdNxneIYDzlsJIhAx2w3HLgVlNdx4S1xGdZ5TRZ4NMCKLhUbeF4C%2FAAoq9D25dNs8PPgiKoP%2BSCuiYHnvDXxdbFd78s56tR%2FL4F5P%2B8Why5mWxtcNv%2FU9Hlfv3ffTrfVfL9N5%2FHPTTmdZHf9B0LDrzJFBgAA

SWC Info output

No response

Expected behavior

The class Dead expression should be eliminated in its entirety, leaving at most return Unknown, 0.

Actual behavior

The entire class Dead definition is retained.

Version

1.15.21

Additional context

No response