RESOLVED FIXED275055
[Regression] Spread of class should not inherit instanceof 
https://bugs.webkit.org/show_bug.cgi?id=275055
Summary [Regression] Spread of class should not inherit instanceof
Max Schmitt
Reported 2024-06-03 06:54:42 PDT
RANGE: https://github.com/WebKit/WebKit/compare/cd9be0fded51cea4c2c3a7c9a21d6b4d341df09d...91f787886ac542eb4148d991b629c028f389f0cf Potential commit which broke it: https://github.com/WebKit/WebKit/commit/804d44f89619bfae3e5e2e21a07669b1fb320d57 Repro: ```ts class Test {field1 = 'foo';} const t1 = { ...new Test() }; console.log(t1 instanceof Test); ``` Expected: false Actual: true V8/Spidermonkey return false. Downstream issue: https://github.com/microsoft/playwright/issues/31132
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Max Schmitt
Comment 1 2024-06-03 07:01:08 PDT
Was able to reproduce it in Safari Technology Preview - t1 is a class instance while in V8/Spidermonkey its just an object.
Radar WebKit Bug Importer
Comment 2 2024-06-03 09:21:39 PDT
<rdar://problem/129168077>
Yusuke Suzuki
Comment 3 2024-06-04 13:07:42 PDT
Pull request: https://github.com/WebKit/WebKit/pull/29511
EWS
Comment 4 2024-06-04 14:09:59 PDT
Committed 279713@main (2069a352b203): <https://commits.webkit.org/279713@main> Reviewed commits have been landed. Closing PR #29511 and removing active labels.
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