Type deduction `nil` => `(some X)?`; `'τ_0_0'` in diagnostic

[dabrahams]

With swift-driver version: 1.62.15 Apple Swift version 5.7.2 (swiftlang-5.7.2.135.5 clang-1400.0.29.51)
Target: arm64-apple-macosx13.0

swift this file

func f() -> some Collection<Int> { [1] }
func g0(x: Bool) -> Optional<some Collection<Int>> {
  f()
}

func g1(x: Bool) -> Optional<some Collection<Int>> {
  x ? f() : nil
}

func g2(x: Bool) -> Optional<some Collection<Int>> {
  if x { return f() }
  return nil // error: generic parameter 'τ_0_0' could not be inferred

Ideally, g2 should compile, and regardless τ shouldn't appear in the diagnostic.