Overloading on borrowing/consuming results in ambiguities with performance hacks removed

[xedin]

Description

One of the test-cases introduced by #76834 depends on a type-checker hack that applies only to initializers - https://github.com/swiftlang/swift/blob/main/lib/Sema/CSSimplify.cpp#L9843-L9855. Removal of this hack makes the code ambiguous.

Reproduction

struct View : ~Escapable {
 init(_ otherBV: borrowing View) {}
 init(_ k: consuming View) {}
}

@lifetime(x)
func getConsumingView(_ x: consuming View) -> View {
  return View(x)
}

Without perf hack this produces:

 error: ambiguous use of 'init(_:)'

Expected behavior

We need to define expected type/flag matching behavior for borrowing and consuming parameters that does not depend on the performance hack(s).

Environment

Swift compiler main branch.

Additional information

No response

[xedin]

cc @meg-gupta

[xedin]

This is actually even worse than just ambiguity because the hack always prefers the first overload which means that flipping overloads around would result in a different pick.

[meg-gupta]

This is an issue with non initializers as well.

This is accepted:

class Klass {}

func test(_ a: borrowing Klass) {}
func test(_ a: consuming Klass) {}

[jckarter]

These should be rejected. We don't allow overloading on ownership qualifiers.

[xedin]

@meg-gupta Yeah, similar hack for one parameter overload sets, but that falls apart when there is more than one.