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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:13 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:13 +0000
commit218caa410aa38c29984be31a5229b9fa717560ee (patch)
treec54bd55eeb6e4c508940a30e94c0032fbd45d677 /src/test/ui/dropck/dropck-eyepatch.rs
parentReleasing progress-linux version 1.67.1+dfsg1-1~progress7.99u1. (diff)
downloadrustc-218caa410aa38c29984be31a5229b9fa717560ee.tar.xz
rustc-218caa410aa38c29984be31a5229b9fa717560ee.zip
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/dropck/dropck-eyepatch.rs')
-rw-r--r--src/test/ui/dropck/dropck-eyepatch.rs123
1 files changed, 0 insertions, 123 deletions
diff --git a/src/test/ui/dropck/dropck-eyepatch.rs b/src/test/ui/dropck/dropck-eyepatch.rs
deleted file mode 100644
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--- a/src/test/ui/dropck/dropck-eyepatch.rs
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@@ -1,123 +0,0 @@
-#![feature(dropck_eyepatch)]
-
-// The point of this test is to illustrate that the `#[may_dangle]`
-// attribute specifically allows, in the context of a type
-// implementing `Drop`, a generic parameter to be instantiated with a
-// lifetime that does not strictly outlive the owning type itself.
-//
-// Here we test that only the expected errors are issued.
-//
-// The illustration is made concrete by comparison with two variations
-// on the type with `#[may_dangle]`:
-//
-// 1. an analogous type that does not implement `Drop` (and thus
-// should exhibit maximal flexibility with respect to dropck), and
-//
-// 2. an analogous type that does not use `#[may_dangle]` (and thus
-// should exhibit the standard limitations imposed by dropck.
-//
-// The types in this file follow a pattern, {D,P,S}{t,r}, where:
-//
-// - D means "I implement Drop"
-//
-// - P means "I implement Drop but guarantee my (first) parameter is
-// pure, i.e., not accessed from the destructor"; no other parameters
-// are pure.
-//
-// - S means "I do not implement Drop"
-//
-// - t suffix is used when the first generic is a type
-//
-// - r suffix is used when the first generic is a lifetime.
-
-use std::fmt;
-
-struct Dt<A: fmt::Debug>(&'static str, A);
-struct Dr<'a, B:'a+fmt::Debug>(&'static str, &'a B);
-struct Pt<A,B: fmt::Debug>(&'static str, A, B);
-struct Pr<'a, 'b, B:'a+'b+fmt::Debug>(&'static str, &'a B, &'b B);
-struct St<A: fmt::Debug>(&'static str, A);
-struct Sr<'a, B:'a+fmt::Debug>(&'static str, &'a B);
-
-impl<A: fmt::Debug> Drop for Dt<A> {
- fn drop(&mut self) { println!("drop {} {:?}", self.0, self.1); }
-}
-impl<'a, B: fmt::Debug> Drop for Dr<'a, B> {
- fn drop(&mut self) { println!("drop {} {:?}", self.0, self.1); }
-}
-unsafe impl<#[may_dangle] A, B: fmt::Debug> Drop for Pt<A, B> {
- // (unsafe to access self.1 due to #[may_dangle] on A)
- fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); }
-}
-unsafe impl<#[may_dangle] 'a, 'b, B: fmt::Debug> Drop for Pr<'a, 'b, B> {
- // (unsafe to access self.1 due to #[may_dangle] on 'a)
- fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); }
-}
-
-
-fn main() {
- use std::cell::Cell;
-
- // We use separate blocks with separate variable to prevent the error
- // messages from being deduplicated.
-
- {
- let c_long;
- let (mut dt, mut dr): (Dt<_>, Dr<_>);
- c_long = Cell::new(1);
-
- // No error: sufficiently long-lived state can be referenced in dtors
- dt = Dt("dt", &c_long);
- dr = Dr("dr", &c_long);
- }
-
- {
- let (c, mut dt, mut dr): (Cell<_>, Dt<_>, Dr<_>);
- c = Cell::new(1);
-
- // No Error: destructor order precisely modelled
- dt = Dt("dt", &c);
- dr = Dr("dr", &c);
- }
-
- {
- let (mut dt, mut dr, c_shortest): (Dt<_>, Dr<_>, Cell<_>);
- c_shortest = Cell::new(1);
-
- // Error: `c_shortest` dies too soon for the references in dtors to be valid.
- dt = Dt("dt", &c_shortest);
- //~^ ERROR `c_shortest` does not live long enough
- dr = Dr("dr", &c_shortest);
- }
-
- {
- let c_long;
- let (mut pt, mut pr, c_shortest): (Pt<_, _>, Pr<_>, Cell<_>);
- c_long = Cell::new(1);
- c_shortest = Cell::new(1);
-
- // No error: Drop impl asserts .1 (A and &'a _) are not accessed
- pt = Pt("pt", &c_shortest, &c_long);
- pr = Pr("pr", &c_shortest, &c_long);
- }
-
- {
- let c_long;
- let (mut pt, mut pr, c_shortest): (Pt<_, _>, Pr<_>, Cell<_>);
- c_long = Cell::new(1);
- c_shortest = Cell::new(1);
- // Error: Drop impl's assertion does not apply to `B` nor `&'b _`
- pt = Pt("pt", &c_long, &c_shortest);
- //~^ ERROR `c_shortest` does not live long enough
- pr = Pr("pr", &c_long, &c_shortest);
- }
-
- {
- let (st, sr, c_shortest): (St<_>, Sr<_>, Cell<_>);
- c_shortest = Cell::new(1);
- // No error: St and Sr have no destructor.
- st = St("st", &c_shortest);
- sr = Sr("sr", &c_shortest);
- }
-}
-fn use_imm<T>(_: &T) { }