[Webkit-unassigned] [Bug 202485] typeof (function that masquerades as undefined) is "function", should be "undefined"

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=202485

Alexey Shvayka <shvaikalesh at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |shvaikalesh at gmail.com
         Resolution|---                         |DUPLICATE

--- Comment #4 from Alexey Shvayka <shvaikalesh at gmail.com> ---
(In reply to Oz from comment #3)
> PASS: typeof window.openDatabase is undefined
> PASS: typeof window.openDatabase is function
> 
> Both can't be true.

Nicely noted, thank you.

That discrepancy was made possible due to peephole optimization in BytecodeGenerator::emitEqualityOpImpl(), which detects patterns like `typeof X === "Y"` and emits different bytecodes depending on Y.
r265907 fixed the `typeof X === "function"` bytecode op to return `false` for masquerader (aka [[IsHTMLDDA]]) objects.

test262 coverage was added in https://github.com/tc39/test262/pull/2706.

*** This bug has been marked as a duplicate of bug 215572 ***

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