#1401. Async for-in tests for patterns

[sgrekhov]

No description provided.

[eernstg]

This gives rise to a bit of pondering!

I get the impression (from the patterns feature specification, and from the open and the closed language repo issues) that await for with patterns have never been discussed, and there is no specification (the word await occurs just once in the patterns feature specification, with no connection to for).

So my first take on this is actually that they do not include support for patterns, and any attempt to use a pattern in an await for is a compile-time error.

In particular, there is no section about await for statements corresponding to this section, and similarly nothing corresponding to the pattern-for-in element section.

If this is true then we're done very quickly: Just test that we get some errors for a couple of simple combinations of await for and patterns.

However, the grammar just mentions that the non-terminal forLoopParts is extended to allow patterns, and there is no reference to the applicability of this enhancement with await-for-in constructs. So maybe. ;-)

Checking out the current situation, I get the impression that it has been implemented and lots of things do work already.

So let's test it "as if it were specified to work", and then we can come up with alternate actions to take if it is far from working in some ways.

Looks good! A couple of typos mentioned in comments.

[sgrekhov]

Updated. Please take another look

[eernstg]

LGTM!