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// RUN: %target-swift-frontend -primary-file %s -emit-sil \
// RUN: -o /dev/null \
// RUN: -verify \
// RUN: -sil-verify-all \
// RUN: -module-name test
// REQUIRES: swift_in_compiler
// REQUIRES: rdar132874319
// ([nonescapable] improve diagnostics for spanofspans.swift; prefer an exclusivity violation to a lifetime error)
// TODO: uncomment the @lifetime annotations when we have component lifetimes.
// @lifetime(elements)
struct Span<T: ~Escapable>: ~Escapable {
// Pretend that 'element' is in separate storage.
var element: T
// @lifetime(elements: t)
init(t: T) {
self.element = t
}
}
// @lifetime(elements)
extension Array {
// @lifetime(span: borrow self)
// @lifetime(span.elements: copy self.elements)
var span: Span<Element> {
_read {
yield Span(t: first!)
}
}
}
// use 'scalars' instead of 'elements' to avoid confusion from nesting
// @lifetime(scalars)
struct Vec<T: ~Escapable>: ~Escapable {
// Pretend that 't' is in separate storage.
var scalar: T
// @lifetime(scalars: t)
init(t: T) {
self.scalar = t
}
// @lifetime(span: self)
// @lifetime(span.elements: self.scalars)
public var span: Span<T> { // expected-note {{it depends on the lifetime of argument 'self'}}
_read {
yield Span(t: scalar)
}
}
}
func useSpan<T>(_: Span<T>) {}
func withFatlifetimes() {
let arr = [1,2,3] // expected-note {{it depends on the lifetime of variable 'arr'}}
// span depends on arr
let span = arr.span
// vec depends on arr
var vec = Vec(t: span) // expected-error {{lifetime-dependent value escapes its scope}}
// expected-note @-3{{it depends on the lifetime of variable 'arr'}}
// expected-note @-1{{this use causes the lifetime-dependent value to escape}}
// spanOfSpans depends on borrow vec
let spanOfSpans = vec.span
// firstSpan depends on spanOfSpans
let firstSpan = spanOfSpans.element
// 🛑 ERROR: vec mutation during borrow
vec.scalar = arr.span // expected-error {{lifetime-dependent value escapes its scope}}
// expected-note {{this use causes the lifetime-dependent value to escape}}
// (firstSpan depends on vec)
useSpan(firstSpan)
// end borrow vec
}
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