Pavel Yaskevich ace4d3ac5e [ConstraintSystem] Detect passing sync closure to async argument early ...

This helps in situations where there are multiple overloads which
differ only in async effect of their parameters. Passing sync argument
to a sync parameter is always preferred and when detected early
allows solver to avoid some of the duplicate work re-solving for
the rest of the path e.g.

```swift
func test<T>(_: () -> T) {}
func test<T>(_: () async -> T) {}

test {
  // sync work
}.op(...)
```

In this case since closure is synchronous first overload of `test`
is always preferred (when it's a match) and solver can skip re-checking
body of the closure and `op` call when it encounters `async` version.

Resolves: rdar://77942193

2021-05-14 13:49:39 -07:00

464 KiB

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