var wg sync.WaitGroup doesn't properly link

[sanjit-bhat]

var wg sync.WaitGroup
wg.Wait()

translates to

let: "wg" := ref (zero_val (struct.t sync.WaitGroup)) in
sync.WaitGroup__Wait (![struct.t sync.WaitGroup] "wg");

This results in Error: The reference sync.WaitGroup__Wait was not found in the current environment.

The current workaround is to switch the allocation to

wg := new(sync.WaitGroup)
wg.Wait()

which translates to

let: "wg" := waitgroup.New #() in
waitgroup.Wait "wg";

We should eventually fix this. CC @upamanyus.

[upamanyus]

This is also a problem for code like

var l sync.Mutex
l.Lock()

It might be that the selectorType in https://github.com/tchajed/goose/blob/5b963b0f176ab516683e173558207814fae66f03/goose.go#L465-L468 is not a types.Pointer as expected by https://github.com/tchajed/goose/blob/5b963b0f176ab516683e173558207814fae66f03/types.go#L231-L232

[zeldovich]

Indeed, was just poking at this, and it's easy enough to get Goose to emit the right code for this case (and even avoid changing any of our existing Goose'd code!): https://github.com/tchajed/goose/compare/master...zeldovich:goose:stack-mutex

Haven't thought about it enough to figure out if this might mean we will incorrectly Goose something in a way that is unsound..