audit AOs with optional parameters

[michaelficarra]

For example, the Call AO's argument list parameter is currently optional, which can make it a footgun for authors and a bit misleading for readers. We should make it mandatory. See tc39/proposal-upsert#65.

reviewed:

• ToPrimitive preferredType
• Call argumentsList
• Construct argumentsList
• Construct newTarget
• CreateListFromArrayLike validElementTypes
• Invoke argumentsList
• IteratorNext value
• ResolveBinding env
• OrdinaryObjectCreate additionalInternalSlotsList
• OrdinaryCreateFromConstructor internalSlotsList
• MakeConstructor writablePrototype
• MakeConstructor prototype
• SetFunctionName prefix
• CreateBuiltinFunction realm
• CreateBuiltinFunction prototype
• CreateBuiltinFunction prefix
• ArrayCreate proto
• ForIn/OfBodyEvaluation iteratorKind

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not yet reviewed:

• InstantiateOrdinaryFunctionExpression name
• InstantiateArrowFunctionExpression name
• DefineMethod functionPrototype
• InstantiateGeneratorFunctionExpression name
• InstantiateAsyncGeneratorFunctionExpression name
• InstantiateAsyncFunctionExpression name
• InstantiateAsyncArrowFunctionExpression name
• LoadRequestedModules hostDefined
• GetExportedNames exportStarSet
• ResolveExport resolveSet
• ExecuteModule capability
• FlattenIntoArray mapperFunction
• FlattenIntoArray thisArg
• AllocateTypedArray length
• AllocateArrayBuffer maxByteLength
• DetachArrayBuffer key
• GetValueFromBuffer isLittleEndian
• SetValueInBuffer isLittleEndian
• AllocateSharedArrayBuffer maxByteLength
• ValidateAtomicAccessOnIntegerTypedArray waitable
• PerformPromiseThen resultCapability
• CreateIteratorFromClosure extraSlots
• AsyncGeneratorCompleteStep realm

[ljharb]

I assume the goal here is to remove footguns, not to remove optional parameters entirely?

[michaelficarra]

It's to consider whether each optional parameter is a net negative or a net positive and remove the former.

[michaelficarra]

An example of OrdinaryObjectCreate's optional parameter being forgotten: tc39/proposal-esm-phase-imports#39

[michaelficarra]

For OrdinaryObjectCreate, it may be a bit too burdensome to make the optional parameter mandatory, but it would be valuable to require it so that it isn't forgotten. We're going to leave it out of this list for now, but explore lifting the internalSlotsList to all the call sites to make it even more explicit, as a separate PR. OrdinaryCreateFromConstructor should match.

[bakkot]

For MakeConstructor, we should replace the existing optional params with a two-state "is a class" vs "is not a function" (or possibly "writable prototype" vs "nonwriteable prototype". This could be a boolean but an enum would be better probably. Then we can do the nonwriteable-prototype stuff inside of ClassDefinitionEvaluation.

[michaelficarra]

CreateBuiltinFunction could use a more extensive refactoring that may include splitting it or changing the parameter list. Out of scope for this for now.