relates to:

• SR-14973 withTaskGroup leaks memory for every task added to the group

Issue Description:

on my machine, the following test program leaks over 3.5 GB of memory per second:

// taskgroup.swift 

@main 
enum Main 
{
    static 
    func main() async
    {
        while true 
        {
            await withTaskGroup(of: Void.self) 
            { 
                _ in
            } 
        }
    }
}

$ swiftenv local DEVELOPMENT-SNAPSHOT-2021-09-07-a
$ swiftc -parse-as-library -O taskgroup.swift 
$ ./taskgroup

this issue only occurs with linux builds. macos builds do not leak memory as far as i have observed.

please note: unlike SR-14973, this memory leak occurs even when no tasks are added to the task group.