Intent use number / bigint union type

[sbc100]

In WebAssembly we are planning on using the union of long long and bigint: WebAssembly/memory64#75

In accordance with the warning in https://webidl.spec.whatwg.org/#idl-union we are opening this issue.

I believe that our use case doesn't run into any issues because we are essentially implementing overloading based on the type of the receiver. The receiver is either a 64-bit memory/table (in which case we expect bitint indexes) or a 32-bit memory/table (in which case we expect number indexes).

[sbc100]

CC @littledan who added the wording about these union types.

[annevk]

I'd be curious to hear @littledan's take, but this seems reasonable to me. Thanks for filing!

[sbc100]

Closing this since we have gone ahead with this change now on the wasm side.

[bvisness]

FYI, we ended up reverting this in WebAssembly/memory64#86 because the special conversion rules for a union of numeric type and bigint would, through ToNumeric/ToNumber, force all string and boolean values to be interpreted as Number instead of BigInt. This is a very confusing special case.