no permission to delete 5th property on BigInt64Array

[dckc]

Build environment: Linux
Target device: xsnap

Description
BigInt64Array has a 5th property whose name is a symbol. It cannot be deleted.

SES requires that all non-whitelisted properties on primordials be deletable.

Steps to Reproduce

run this as a module, i.e. in strict mode:

// surprising property on BigInt64Array
// undeletable even though not frozen
// will be a problem when SES whitelist...

const props = Reflect.ownKeys(BigInt64Array);
print(typeof props[4]);
delete BigInt64Array[props[4]];  // must succeed in order for SES to work. non-whitelist must be deletable
// bug1.js:6: exception: bug1.js: delete ?: no permission (strict mode)!

cc @warner @erights @kriskowal @phoddie

[phoddie]

This behavior is a consequence of an internal slot being made visible to scripts. The mistake is that an internal slot is placed in the wrong position, after a public slot. This occurs for all TypedArray constructors, not only BigInt64Array. We'll have a fix posted in a little bit.

[phoddie]

Fix is now available.

[dckc]

verified using 748fda9

print(typeof props[4]); gives undefined. And there's no exception from delete.

And String(sonOfMonster) from #480 no longer throws.