#isolation within a lazy var initializer should evaluate to the instance's static isolation

[mattmassicotte]

Description

I've discovered that #isolation always returns nil for lazy var initializers. Today, all of these print nil.

Reproduction

func captureIsolation(isolation: isolated (any Actor)? = #isolation) -> Int {
	print(isolation)

	return 1
}

class NoIsolation {
	// here's nil and that makes sense
	lazy var value = captureIsolation()
}

actor MyActor {
	// I think #isolation should evaluate to self here
	lazy var value = captureIsolation()
}

@MainActor
class GlobalClass {
	// I think #isolation should evaluate to MainActor.shared here
	lazy var value = captureIsolation()
}

_ = NoIsolation().value
_ = await MyActor().value
_ = GlobalClass().value

Expected behavior

I think the static isolation should always be knowable in the actor and global actor situations, shouldn't it?

Environment

Apple Swift version 6.1-dev (LLVM a321a98f4e5b06a, Swift 7a0a6e7)
Target: arm64-apple-macosx15.0

Additional information

No response