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// RUN: %target-swift-frontend %s -emit-sil \
// RUN: -o /dev/null \
// RUN: -verify \
// RUN: -sil-verify-all \
// RUN: -module-name test \
// RUN: -enable-experimental-feature LifetimeDependence
// REQUIRES: swift_in_compiler
// REQUIRES: swift_feature_LifetimeDependence
// TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence should be expressed by a builtin that is
// hidden within the function body.
@_unsafeNonescapableResult
@lifetime(source)
func unsafeLifetime<T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable>(
dependent: consuming T, dependsOn source: borrowing U)
-> T {
dependent
}
struct BV : ~Escapable {
let p: UnsafeRawPointer
let i: Int
@lifetime(borrow p)
init(_ p: UnsafeRawPointer, _ i: Int) {
self.p = p
self.i = i
}
@lifetime(borrow p)
init(independent p: UnsafeRawPointer, _ i: Int) {
self.p = p
self.i = i
}
@lifetime(self)
consuming func derive() -> BV {
// Technically, this "new" view does not depend on the 'view' argument.
// This unsafely creates a new view with no dependence.
let bv = BV(independent: self.p, self.i)
return unsafeLifetime(dependent: bv, dependsOn: self)
}
}
// Nonescapable wrapper.
struct NEBV : ~Escapable {
var bv: BV
// Test lifetime inheritance through initialization.
init(_ bv: consuming BV) {
self.bv = bv
}
var view: BV {
_read {
yield bv
}
_modify {
yield &bv
}
}
@lifetime(borrow self)
func borrowedView() -> BV {
bv
}
}
// Test lifetime inheritance through chained consumes.
@lifetime(bv)
func bv_derive(bv: consuming BV) -> BV {
bv.derive()
}
// Test lifetime inheritance through stored properties.
@lifetime(nebv)
func ne_extract_member(nebv: consuming NEBV) -> BV {
return nebv.bv
}
@lifetime(nebv)
func ne_yield_member(nebv: consuming NEBV) -> BV {
return nebv.view
}
func bv_consume(_ x: consuming BV) {}
// It is ok to consume the aggregate before the property.
// The property's lifetime must exceed the aggregate's.
func nebv_consume_member(nebv: consuming NEBV) {
let bv = nebv.bv
_ = consume nebv
bv_consume(bv)
}
func nebv_consume_after_yield(nebv: consuming NEBV) {
let view = nebv.view
_ = consume nebv
bv_consume(view)
}
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