XS: Proxy ownKeys trap accepts a non-object result

[d01c2]

Build environment: macOS 26.5.2

Moddable SDK version:

• Installed via jsvu, so there is no SDK source tree / git describe.
• Engine reports: XS 17.9.1, slot 32 bytes, ID 4 bytes

Target device: desktop (host xs)

Description
Object.seal completes successfully when a Proxy's ownKeys trap returns a non-object value.

According to the Proxy [[OwnPropertyKeys]] method, the trap result is passed to CreateListFromArrayLike.

That operation must throw a TypeError if its argument is not an Object. Since 0 is a Number primitive, the call should throw.

Steps to Reproduce

$ xst -e 'Object.seal(new Proxy({}, { ownKeys: () => 0 })); print("completed")'
completed

Expected behavior
A TypeError is thrown.

For comparison, V8 (15.3.27):

$ v8 -e 'try { Object.seal(new Proxy({}, { ownKeys: () => 0 })); } catch (e) { print(e.name); }'
TypeError

Other information
The same issue is directly observable with Reflect.ownKeys, which returns an empty array instead of throwing:

$ xst -e 'print(JSON.stringify(Reflect.ownKeys(new Proxy({}, { ownKeys: () => 0 }))))'
[]

Reflect.ownKeys should also throw a TypeError.