Should 'using' suppress exceptions from @@dispose when already throwing an exception

[rbuckton]

This was brought up by @waldemarhorwat in the July TC39 meeting. Java's try-with-resources block will suppress exceptions raised when disposing resources if already propagating an exception from the body.

However, there are two points that cause me concern about adopting this behavior:

• This behavior would differ significantly from a regular try..finally statement.
• Java has a way to retrieve these suppressed exceptions by calling the Throwable.getSuppressed() method on the exception thrown. ECMAScript does not have a reliable way to provide this as it is possible to throw a non-Error value.

Should we consider following Java's lead here and perform the same suppression?

[littledan]

My intuition here is to match try/finally and not suppress the error, but this is not a strongly held opinion.

[benjamingr]

I think we should not suppress the exception. I can gather more feedback from Node if you'd like :)

[rbuckton]

Addressed by the addition of AggregateError in #26.